WTNT42 KNHC 252029 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST WED AUG 25 2010 THE FIFTH TROPICAL STORM OF THE SEASON...TROPICAL STORM EARL...HAS FORMED IN THE EASTERN ATLANTIC...ONE WEEK EARLIER THAN CLIMATOLOGY. HIGH RESOLUTION SATELLITE IMAGES SHOW THAT THE CIRCULATION HAS CONTINUE TO GROW AND THE CONVECTION...BOTH IN CLUSTERS AND CURVED BANDS HAS CONTINUE TO BECOME BETTER ORGANIZED. T-NUMBERS FROM TAFB AND SAB HAVE REACHED 3.0 AND 2.5 ON THE DVORAK SCALE INDICATING THAT THE WINDS HAVE INCREASED TO AT LEAST 35 KNOTS. MOST OF THE GLOBAL MODELS AS WELL AS SHIPS GUIDANCE DEPICT AN ENVIRONMENT OF RELATIVELY LOW SHEAR ACROSS THE TROPICAL ATLANTIC. THE LOW SHEAR COMBINED WITH UNUSUALLY WARM OCEAN WOULD FAVOR A GRADUAL STRENGTHENING. THE OFFICIAL FORECAST CALLS FOR EARL TO BECOME A HURRICANE IN ABOUT TWO DAYS. THE BEST ESTIMATE OF THE INITIAL MOTION IS 275/14 KNOTS. MOST OF THE GLOBAL MODELS SHOW A PERSISTENT SUBTROPICAL RIDGE EXTENDING FROM AFRICA TO NEAR 60 DEGREES WEST. THIS STEERING PATTERN WILL LIKELY KEEP THE CYCLONE ON A GENERAL WESTWARD TRACK FOR THE NEXT 3 TO 4 DAYS. A GRADUAL TURN MORE TO THE WEST-NORTHWEST IS FORECAST AT THE END OF THE FORECAST PERIOD AS THE CYCLONE REACHES THE WESTERN EDGE OF THE SUBTROPICAL RIDGE. THE OFFICIAL FIVE DAY FORECAST POSITION WAS ADJUSTED SOUTHWARD A LITTLE BIT...AND IS BASICALLY ON TOP OF THE GFS AND THE ECMWF LOCATION FOR THAT TIME PERIOD. THIS WAS BASED ON THE REMARKABLY GOOD AGREEMENT OF THESE TWO RELIABLE MODELS IN FIVE DAYS. ALTHOUGH MOST OF THE GUIDANCE HAS SHIFTED SOUTHWARD A LITTLE BIT...THE CORE OF THE CYCLONE IS STILL FORECAST TO PASS TO THE NORTH OF THE LEEWARD ISLANDS. LETS SEE WHAT HAPPENS IN THE NEXT MODEL CYCLE. FORECAST POSITIONS AND MAX WINDS INITIAL 25/2100Z 14.4N 32.2W 35 KT 12HR VT 26/0600Z 14.6N 34.6W 40 KT 24HR VT 26/1800Z 15.0N 38.0W 45 KT 36HR VT 27/0600Z 15.5N 41.0W 55 KT 48HR VT 27/1800Z 16.0N 44.0W 65 KT 72HR VT 28/1800Z 17.0N 50.0W 75 KT 96HR VT 29/1800Z 18.0N 55.0W 80 KT 120HR VT 30/1800Z 20.0N 60.0W 80 KT $$ FORECASTER AVILA WTNT42 KNHC 260241 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST WED AUG 25 2010 THE OVERALL ORGANIZATION OF EARL HAS CHANGED LITTLE THIS EVENING. INFRARED SATELLITE IMAGERY SHOWS SEVERAL CURVED BANDS OF THUNDERSTORMS OVER THE NORTHERN SEMICIRCLE OF THE CYCLONE. THE INITIAL INTENSITY REMAINS 35 KT AND IS IN AGREEMENT WITH THE LATEST SATELLITE ESTIMATES. THE ENVIRONMENT AHEAD OF EARL APPEARS CONDUCIVE FOR GRADUAL STRENGTHENING. BOTH THE STATISTICAL AND DYNAMICAL MODELS INTENSIFY THE CYCLONE INTO A HURRICANE WITHIN A COUPLE OF DAYS. THE LATEST ITERATIONS OF THE GFDL AND HWRF MODELS SHOW HIGHER WIND SPEEDS AT DAYS 4 AND 5 THAN BEFORE. THE INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS NHC ADVISORY THROUGH 72 HOURS...BUT IS ADJUSTED A LITTLE HIGHER THEREAFTER TO BE MORE IN LINE WITH THE INTENSITY CONSENSUS...ICON. SINCE THE CENTER HAS BEEN DIFFICULT TO DISCERN IN INFRARED IMAGERY...THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 275/14. EARL IS EXPECTED TO CONTINUE WESTWARD TO THE SOUTH OF A SUBTROPICAL RIDGE DURING THE NEXT 2-3 DAYS. A TURN TOWARD THE WEST-NORTHWEST IS EXPECTED AROUND DAY 4 AS THE CYCLONE NEARS THE WESTERN PORTION OF THE RIDGE. THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO THROUGH 72 HOURS AND THE OFFICIAL FORECAST IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE THROUGH THAT TIME. THEREAFTER... THERE IS MORE SPREAD IN THE GUIDANCE WITH THE UKMET...NOGAPS...AND GFDN SHOWING AN EARLIER TURN TOWARD THE WEST-NORTHWEST. FOR NOW... THE OFFICIAL FORECAST WILL REMAIN ON THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE AT DAYS 4 AND 5...CLOSER TO THE USUALLY RELIABLE ECMWF...GFS...AND GFDL MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 26/0300Z 14.7N 33.6W 35 KT 12HR VT 26/1200Z 15.0N 35.9W 40 KT 24HR VT 27/0000Z 15.5N 39.1W 45 KT 36HR VT 27/1200Z 16.0N 42.3W 55 KT 48HR VT 28/0000Z 16.4N 45.4W 65 KT 72HR VT 29/0000Z 17.4N 51.3W 75 KT 96HR VT 30/0000Z 19.0N 56.5W 85 KT 120HR VT 31/0000Z 21.5N 60.5W 90 KT $$ FORECASTER BROWN WTNT42 KNHC 260848 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST THU AUG 26 2010 CONVENTIONAL SATELLITE IMAGERY INDICATES THAT THE SPIRAL BANDS AROUND EARL HAVE BECOME BETTER ORGANIZED THIS MORNING... PARTICULARLY OVER THE WESTERN PORTION OF THE CYCLONE. THE CYCLONE STRUCTURE...HOWEVER...IS STILL A BIT ELONGATED ALONG A SOUTHWEST TO NORTHEAST AXIS. DVORAK SATELLITE CURRENT INTENSITY ESTIMATES FROM TAFB AND SAB ARE 45 AND 35 KT..RESPECTIVELY. USING A BLEND OF THE TWO...THE INITIAL INTENSITY IS INCREASED TO 40 KT. THE OCEAN IS WARM AND THE SHEAR IS LOW...CREATING AN ENVIRONMENT CONDUCIVE FOR STRENGTHENING DURING THE ENTIRE FORECAST PERIOD. IN FACT...THE LGEM...HWRF...AND SHIPS MODELS ALL SHOW THE CYCLONE BECOMING A HURRICANE IN 2 DAYS. THE OFFICIAL FORECAST FOLLOWS SUIT AND ALSO BRINGS EARL TO CATEGORY TWO INTENSITY BY DAY 5. THE CENTER OF EARL HAS BEEN RATHER DIFFICULT TO LOCATE THIS MORNING. A 2315 UTC ASCAT OVERPASS INDICATED AN ELONGATED CENTER NEAR THE CONVECTION OVER THE SOUTHERN PORTION OF THE SYSTEM...WELL TO THE SOUTH OF THE PREVIOUS ADVISORY POSITION. HOWEVER...A SUBSEQUENT AMSU-B MICROWAVE PASS AT 2318 UTC AND A RECENT 0430 UTC TRMM IMAGE SUGGESTED THE CENTER IS LOCATED TO THE NORTHEAST OF THE AFOREMENTIONED ASCAT PASS...MUCH CLOSER TO THE PREVIOUS BEST TRACK. FOR THIS ADVISORY...AND BASED ON THESE DATA...CONTINUITY WILL BE MAINTAINED AND THE INITIAL POSITION IS BE NEAR THE NORTHERN CLUSTER OF DEEP CONVECTION AND CLOSE TO THE TRMM FIX. IF THE CIRCULATION CENTER DOES REFORM FARTHER SOUTH...THE FORECAST TRACK WILL HAVE TO BE ADJUSTED SOUTH...OR TO THE LEFT OF THIS ADVISORY PACKAGE. EARL IS MOVING TOWARD THE WEST-NORTHWEST...AN ESTIMATED 285 DEGREES AT 13 KT. THE TROPICAL STORM IS EMBEDDED WITHIN THE DEEP TROPICAL ATLANTIC TRADE WIND FLOW AND SHOULD CONTINUE ON THIS GENERAL TRACK OVER THE NEXT 48 TO 72 HOURS. AFTERWARD...A TURN TOWARD THE WEST-NORTHWEST IS EXPECTED AS THE CYCLONE BEGINS TO MOVE TOWARD A BREAK IN THE SUBTROPICAL RIDGE. WITH THE EXCEPTION OF NOGAPS AND THE NAVY GFDN...WHICH ARE BOTH INDICATING AN EARLIER TURN TOWARD THE NORTHWEST...THE DYNAMICAL MODELS ARE TIGHTLY CLUSTERED THROUGH DAY 5. THE NHC FORECAST TRACK IS BASED ON THE TVCN MODEL CONSENSUS AND IS CLOSE TO THE ECMWF AND GFS. FORECAST POSITIONS AND MAX WINDS INITIAL 26/0900Z 15.2N 34.8W 40 KT 12HR VT 26/1800Z 15.7N 37.2W 45 KT 24HR VT 27/0600Z 16.4N 40.3W 50 KT 36HR VT 27/1800Z 16.6N 43.7W 60 KT 48HR VT 28/0600Z 16.7N 47.0W 70 KT 72HR VT 29/0600Z 17.9N 52.3W 80 KT 96HR VT 30/0600Z 20.0N 57.0W 90 KT 120HR VT 31/0600Z 22.5N 60.0W 95 KT $$ FORECASTER ROBERTS/BRENNAN WTNT42 KNHC 261459 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST THU AUG 26 2010 VISIBLE AND MICROWAVE SATELLITE IMAGERY INDICATE EARL HAS NOT BECOME ANY BETTER ORGANIZED SINCE THE LAST ADVISORY. IN FACT...THE INNER CORE CONVECTION HAS ERODED DUE TO DRY AIR ENTRAINMENT NOTED IN CONVENTIONAL WATER VAPOR IMAGERY AND IN A 0735Z SSMI WATER VAPOR IMAGE. THE INITIAL INTENSITY WILL REMAIN 40 KT FOR THIS ADVISORY BASED ON A BLEND OF SATELLITE INTENSITY ESTIMATES OF 45 KT AND 35 KT FROM TAFB AND SAB...RESPECTIVELY. THE CENTER OF EARL HAS BEEN REPOSITIONED ABOUT 30 NMI SOUTH OF THE PREVIOUS ADVISORY AND FORECAST TRACK BASED ON A BLEND OF VISIBLE AND MICROWAVE FIXES. THE INITIAL MOTION ESTIMATE IS A 24-HOUR AVERAGE OF 275/15...AFTER SMOOTHING THROUGH ALL THE WIGGLES AND WOBBLES IN THE FIXES. THE OFFICIAL FORECAST TRACK WAS SHIFTED SOUTH OF THE PREVIOUS ADVISORY DUE IN PART TO THE MORE SOUTHWARD INITIAL POSITION. OTHERWISE...THERE REMAINS NO SIGNIFICANT CHANGE TO THE PREVIOUS TRACK REASONING. EARL IS EXPECTED TO MOVE STEADILY WEST TO WEST-NORTHWESTWARD FOR THE NEXT 72 HOURS AND THEN GRADUALLY TURN NORTHWESTWARD AND SLOW DOWN AS THE CYCLONE APPROACHES A WEAKNESS IN THE SUBTROPICAL RIDGE BETWEEN BERMUDA AND THE LEEWARD ISLANDS. THIS WEAKNESS IN THE STEERING FLOW IS THE COMBINED EFFECTS OF HURRICANE DANIELLE AND A MID-LATITUDE TROUGH FORECAST TO CAPTURE AND LIFT OUT THAT HURRICANE TO THE NORTHEAST. IF DANIELLE RECURVES FASTER THAN CURRENTLY EXPECTED...WHICH THE UKMET AND ECMWF ARE HINTING AT... THEN THE RIDGE TO THE NORTH OF EARL COULD BUILD BACK IN SOONER AND KEEP EARL ON A SLOWER WEST-NORTHWESTWARD TRACK THAN INDICATED BY THE OFFICIAL FORECAST TRACK. THE ADVISORY TRACK LIES ALONG THE NORTHERN EDGE OF THE TIGHTLY PACKED MODEL GUIDANCE SUITE AND SIMILAR TO THE SPEED OF THE CONSENSUS MODEL...TVCN. ALL OF THE MODELS INDICATE THAT THE VERTICAL SHEAR SHOULD REMAIN QUITE LOW THROUGH 72 HOURS OR SO...WHICH WOULD FAVOR SIGNIFICANT INTENSIFICATION. HOWEVER...THE DRY MID-LEVEL ENVIRONMENT THAT EARL IS FORECAST TO MOVE THROUGH DURING THAT TIME IS EXPECTED TO RESULT IN A SLOWER THAN NORMAL RATE OF INTENSIFICATION. HOWEVER...BY DAYS 4 AND 5...EARL IS FORECAST TO MOVE INTO THE SOUTHWESTERLY PERIPHERY OF SYNOPTIC-SCALE 200 MB ANTICYCLONE...WHICH GENERALLY FAVORS DEVELOPMENT DUE TO ENHANCED OUTFLOW TO THE NORTH AND SOUTH OF THE CYCLONE. IT IS POSSIBLE THAT EARL COULD REACH MAJOR HURRICANE STRENGTH BY THAT TIME...AS INDICATED BY THE HWRF MODEL. THE OFFICIAL INTENSITY FORECAST IS A BLEND OF THE VARIOUS INTENSITY MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 26/1500Z 14.9N 37.1W 40 KT 12HR VT 27/0000Z 15.4N 39.4W 45 KT 24HR VT 27/1200Z 15.7N 42.6W 50 KT 36HR VT 28/0000Z 16.1N 46.0W 55 KT 48HR VT 28/1200Z 16.5N 49.1W 65 KT 72HR VT 29/1200Z 17.8N 54.4W 75 KT 96HR VT 30/1200Z 20.0N 58.5W 85 KT 120HR VT 31/1200Z 22.5N 61.0W 95 KT $$ FORECASTER STEWART WTNT42 KNHC 262055 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST THU AUG 26 2010 INNER-CORE CONVECTION REMAINS SHALLOW AND LOOSELY ORGANIZED...BUT THE OVERALL CLOUD PATTERN AND STRUCTURE HAS IMPROVED AND BECOME MORE CIRCULAR IN VISIBLE IMAGERY. AN 1150Z ASCAT PASS EARLIER THIS MORNING INDICATED EARL POSSESSED A LARGE SWATH OF 34-KT WINDS MORE THAN 90 NMI NORTH OF THE CENTER...WHICH WOULD SUPPORT HIGHER NEAR-SURFACE WINDS GIVEN THE LOW BIAS OF ASCAT WINDS. THE INITIAL INTENSITY WILL REMAIN 40 KT FOR THIS ADVISORY BASED ON A BLEND OF SATELLITE CURRENT INTENSITY ESTIMATES OF 45 KT AND 35 KT FROM TAFB AND SAB...RESPECTIVELY..AND THE AFOREMENTIONED ASCAT WINDS. EARL ALSO PASSED JUST NORTH OF PIRATA BUOY 13008 AROUND 1800Z...WHICH REPORTED A PRESSURE OF 1003 MB. THIS PRESSURE VALUE WOULD ALSO SUPPORT AN INTENSITY OF ABOUT 40 KT. EARL REMAINS ON TRACK WITH AN INITIAL MOTION ESTIMATE OF 280/16. THE OFFICIAL FORECAST TRACK REMAINS UNCHANGED THROUGH 48 HOURS AS THE STRONG SUBTROPICAL RIDGE TO THE NORTH REMAINS IN PLACE. BY 72 HOURS...EARL IS FORECAST TO APPROACH A WEAKNESS IN THE RIDGE AXIS INDUCED BY DANIELLE AND A MID-LATITUDE TROUGH THAT IS FORECAST TO HELP RECURVE THAT HURRICANE TO THE NORTHEAST. AS EARL APPROACHES THE WEAKNESS IN THE RIDGE...IT IS EXPECTED TO GRADUALLY SLOW DOWN AND TURN MORE TOWARD THE NORTHWEST. THE 12Z GFS AND ECMWF MODELS ARE NOW FORECASTING DANIELLE TO RECURVE TO THE NORTHEAST FASTER THAN PREVIOUSLY EXPECTED...WHICH ALSO ALLOWS THE SUBTROPICAL RIDGE BETWEEN EARL AND DANIELLE TO BUILD BACK IN TO THE NORTH OF EARL. THIS DEVELOPING FLOW PATTERN WOULD FORCE EARL MORE WESTWARD THAN NORTHWARD AT A SLOWER FORWARD SPEED BY DAYS 4 AND 5. THE OFFICIAL FORECAST TRACK IS JUST AN UPDATE OF THE PREVIOUS TRACK THROUGH 72 HOURS...AND THEN A LITTLE TO THE LEFT OF THE PREVIOUS ADVISORY AFTER THAT. THE FORECAST REMAINS ON THE NORTHERN OR RIGHT EDGE OF THE GUIDANCE ENVELOPE IN THE EVENT THE CIRCULATION CENTER REDEVELOPS FARTHER NORTH WITHIN THE BROAD CONVECTIVE CLOUD MASS. ALTHOUGH THE MODELS CONTINUE TO FORECAST LOW VERTICAL SHEAR ACROSS EARL THROUGH THE NEXT 24-36 HOURS...THE CYCLONE STILL HAS TO TRAVERSE THROUGH AN ENVIRONMENT OF DRY MID-LEVEL AIR. BY 48 HOURS...SOME OF THE NORTHERLY OUTFLOW ON THE EAST SIDE OF HURRICANE DANIELLE IS EXPECTED TO CREATE SOME MODEST NORTHERLY SHEAR ACROSS EARL...WHICH MAY INHIBIT THE DEVELOPMENT PROCESS. HOWEVER...BY DAYS 4 AND 5...THE UPPER-LEVEL FLOW PATTERN IS FORECAST TO BECOME MORE FAVORABLE FOR DEVELOPMENT AS EARL MOVES INTO THE SOUTHWEST PERIPHERY OF A LARGE SYNOPTIC-SCALE 200 MB ANTICYCLONE...WHICH SHOULD ACT TO ENHANCE THE OUTFLOW TO THE NORTH AND SOUTH OF THE CYCLONE. THE GFDL AND HWRF MODELS ARE ALSO INDICATING DEVELOPMENT OF THIS FAVORABLE OUTFLOW PATTERN AND STRENGTHEN EARL TO CATEGORY 4 INTENSITY BY 120 HOURS. THE OFFICIAL INTENSITY FORECAST IS A LITTLE LOWER THAN THE SHIPS AND LGEM MODELS THROUGH 72 HOURS AND THEN HIGHER AT DAYS 4 AND 5...BUT NOT AS HIGH AS THE GFDL/HWRF MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 26/2100Z 15.2N 38.8W 40 KT 12HR VT 27/0600Z 15.6N 41.2W 45 KT 24HR VT 27/1800Z 15.9N 44.4W 55 KT 36HR VT 28/0600Z 16.3N 47.7W 60 KT 48HR VT 28/1800Z 16.7N 50.8W 65 KT 72HR VT 29/1800Z 18.2N 55.9W 75 KT 96HR VT 30/1800Z 20.6N 60.0W 85 KT 120HR VT 31/1800Z 23.0N 62.5W 100 KT $$ FORECASTER STEWART WTNT42 KNHC 270232 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST THU AUG 26 2010 AFTER LOSING MOST OF ITS DEEP CONVECTION DURING THE AFTERNOON...EARL HAS DEVELOPED NEW THUNDERSTORM CELLS AROUND THE LARGE AND WELL-DEFINED CIRCULATION TONIGHT. T-NUMBERS HAVE NOT CHANGED AND STILL SUPPORT AN INITIAL INTENSITY OF 40 KNOTS. EARL IS MOVING TOWARD A WARMER OCEAN AND WILL LIKELY CONTINUE UNDER RELATIVELY LIGHT SHEAR FOR THE NEXT SEVERAL DAYS. GLOBAL MODELS INDICATE THAT EARL WILL DEVELOP A DEEP CIRCULATION SURROUNDED BY A LARGE UPPER-LEVEL OUTFLOW. THIS NORMALLY IS AN INDICATION OF STRENGTHENING AND IN FACT...BOTH THE HWRF AND GFDL MODELS DEVELOP EARL INTO AN INTENSE HURRICANE BY THE END OF THE FORECAST PERIOD. ON THIS BASIS...THE OFFICIAL FORECAST CALLS FOR EARL TO BECOME A HURRICANE IN A COUPLE OF DAYS WITH ADDITIONAL INTENSIFICATION THEREAFTER. ALTHOUGH THERE IS A LARGE CIRCULATION...THE CENTER IS DIFFICULT TO LOCATE. USING ENHANCED SATELLITE IMAGERY AND MICROWAVE DATA...THE BEST ESTIMATE OF THE INITIAL MOTION IS 280 DEGREES AT 15 KNOTS. EARL IS TRAPPED SOUTH OF A STRONG SUBTROPICAL RIDGE EXTENDING FROM AFRICA WESTWARD TO NEAR 60 DEGREES WEST. THIS PATTERN WILL KEEP THE CYCLONE ON A GENERAL WESTWARD TRACK FOR THE NEXT 3 DAYS OR SO. EARL SHOULD THEN BEGIN TO TURN MORE TO THE WEST-NORTHWEST AND NORTHWEST AS IT APPROACHES 60W WHERE THERE IS A PERSISTENT WEAKNESS IN THE SUBTROPICAL RIDGE. MOST OF THE TRACK MODELS ARE IN REMARKABLY GOOD AGREEMENT AND THE OFFICIAL FORECAST IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE...BUT BIASED TO THE RELIABLE GFS AND ECMWF MODELS. FORECAST POSITIONS AND MAX WINDS INITIAL 27/0300Z 15.5N 40.2W 40 KT 12HR VT 27/1200Z 16.0N 42.8W 40 KT 24HR VT 28/0000Z 16.3N 46.0W 45 KT 36HR VT 28/1200Z 16.5N 49.3W 55 KT 48HR VT 29/0000Z 16.7N 52.5W 65 KT 72HR VT 30/0000Z 18.5N 58.0W 75 KT 96HR VT 31/0000Z 21.0N 62.0W 85 KT 120HR VT 01/0000Z 24.0N 65.0W 100 KT $$ FORECASTER AVILA WTNT42 KNHC 270839 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST FRI AUG 27 2010 EARL HAS GENERALLY CHANGED LITTLE IN ORGANIZATION DURING THE LAST SEVERAL HOURS. DEEP CONVECTION THAT REFORMED AROUND 00 UTC HAS PERSISTED IN BROAD CURVED BANDS MAINLY TO THE WEST OF THE ESTIMATED LOW-LEVEL CENTER POSITION. SATELLITE INTENSITY ESTIMATES ARE 45 KT AND 35 KT FROM TAFB AND SAB...RESPECTIVELY...AND THE INITIAL INTENSITY WILL BE HELD AT 40 KT. THE ATMOSPHERIC AND OCEANIC ENVIRONMENTS APPEAR FAVORABLE FOR INTENSIFICATION...AND INDEED ALL OF THE INTENSITY MODELS SHOW EARL STRENGTHENING THROUGHOUT THE FORECAST PERIOD. THIS IS REFLECTED IN THE NHC OFFICIAL FORECAST WHICH BRINGS EARL TO HURRICANE STRENGTH WITHIN 2 DAYS AND SHOWS ADDITIONAL STRENGTHENING THEREAFTER. EARL CONTINUES TO MOVE ON A CONSISTENT WESTWARD PATH AND THE INITIAL MOTION ESTIMATE IS 275/15. A GENERAL WESTWARD MOTION IS FORECAST TO CONTINUE OVER THE NEXT COUPLE OF DAYS AS THE CYCLONE REMAINS STEERED BY A NARROW MID-LEVEL RIDGE CENTERED ALONG 25N. EARL IS EXPECTED TO APPROACH A BREAK IN THE RIDGE...WHICH WILL BE ENHANCED BY HURRICANE DANIELLE...IN ABOUT 3 DAYS AND THAT SHOULD INDUCE A TURN TO THE WEST-NORTHWEST TO NORTHWEST WITH A DECREASE IN FORWARD SPEED. THE TRACK MODEL GUIDANCE REMAINS TIGHTLY CLUSTERED FOR MUCH OF THE PERIOD AND THE NHC OFFICIAL TRACK FORECAST IS ESSENTIALLY AN UPDATE OF THE PREVIOUS ONE. FORECAST POSITIONS AND MAX WINDS INITIAL 27/0900Z 15.9N 41.6W 40 KT 12HR VT 27/1800Z 16.2N 44.2W 45 KT 24HR VT 28/0600Z 16.4N 47.4W 50 KT 36HR VT 28/1800Z 16.6N 50.7W 55 KT 48HR VT 29/0600Z 17.2N 53.9W 65 KT 72HR VT 30/0600Z 19.0N 59.0W 75 KT 96HR VT 31/0600Z 21.5N 62.5W 85 KT 120HR VT 01/0600Z 24.5N 65.0W 100 KT $$ FORECASTER CANGIALOSI WTNT42 KNHC 271431 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 9 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST FRI AUG 27 2010 THE OVERALL PATTERN HAS NOT CHANGED MUCH DURING THE PAST SEVERAL HOURS. EARL CONTINUES TO HAVE A LARGE CIRCULATION...MODERATE BANDS OF DEEP CONVECTION AND FAIR OUTFLOW. DVORAK SATELLITE ESTIMATES STILL SUPPORT AN INITIAL INTENSITY OF 40 KNOTS. THE OCEAN AND THE ATMOSPHERE APPEAR TO BE FAVORABLE FOR INTENSIFICATION...AND THIS IS REFLECTED IN THE INTENSITY GUIDANCE WHICH ARE ALL SHOWING STRENGTHENING. IN FACT...BOTH GFDL AND HWRF ARE AGGRESSIVE IN MAKING EARL AN INTENSE HURRICANE IN 5 DAYS. ACCORDINGLY...THE OFFICIAL FORECAST SHOWS EARL BECOMING A MAJOR HURRICANE BY THE END OF THE FORECAST PERIOD. EARL IS MOVING TOWARD THE WEST OR 270 DEGREES AT 15 KNOTS EMBEDDED WITHIN THE EASTERLY FLOW AROUND THE SOUTH SIDE OF A NARROW SUBTROPICAL RIDGE. THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT DAY OR TWO. THEREAFTER...THE CYCLONE WILL BEGIN TO APPROACH A WEAKNESS IN THE SUBTROPICAL RIDGE AND SHOULD BEGIN TO TURN MORE TO THE WEST-NORTHWEST AND NORTHWEST WITH A DECREASE IN FORWARD SPEED. THERE IS HIGH CONFIDENCE IN THE TRACK FORECAST FOR THE FIRST 48 HOURS SINCE THE STEERING CURRENTS ARE WELL ESTABLISHED. ONCE THE CYCLONE BEGINS TO APPROACH 60 DEGREES WEST... THE TRACK MODELS ARE IN LESS AGREEMENT AND THERE IS LESS CONFIDENCE IN THE FORECAST. THE OFFICIAL FORECAST IS IN BETWEEN THE GFS AND THE ECMWF AND IS A LITTLE BIT SOUTH OF THE PREVIOUS ONE. A DEVIATION TO THE SOUTH OF THE CURRENT FORECAST TRACK COULD BRING EARL INTO THE NORTHERN LEEWARD ISLANDS. WITH THE WEEKEND COMING...RESIDENTS IN THESE ISLANDS SHOULD CLOSELY MONITOR THE PROGRESS OF EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 27/1500Z 15.7N 43.6W 40 KT 12HR VT 28/0000Z 15.8N 45.8W 45 KT 24HR VT 28/1200Z 16.3N 49.5W 50 KT 36HR VT 29/0000Z 16.8N 53.0W 60 KT 48HR VT 29/1200Z 17.5N 56.0W 70 KT 72HR VT 30/1200Z 18.8N 60.5W 80 KT 96HR VT 31/1200Z 21.5N 64.0W 90 KT 120HR VT 01/1200Z 25.0N 67.0W 100 KT $$ FORECASTER AVILA WTNT42 KNHC 272030 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 10 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST FRI AUG 27 2010 EARL CONTINUES TO HAVE A LARGE CIRCULATION AND THE ASSOCIATED DEEP CONVECTION HAS BEEN PULSATING DURING THE PAST SEVERAL HOURS. CURRENTLY...VISIBLE SATELLITE IMAGES SHOW SEVERAL CONVECTIVE CYCLONICALLY CURVED BANDS DEVELOPING ON ITS WESTERN SEMICIRCLE. AN EARLIER ASCAT PASS AS WELL AS THE LATEST SATELLITE ESTIMATES INDICATE THAT THE INITIAL INTENSITY REMAINS AT 40 KNOTS. GIVEN THE CURRENT POORLY ORGANIZED PATTERN...NO SIGNIFICANT CHANGE IS ANTICIPATED TONIGHT. HOWEVER...EARL WILL BE MOVING SOON OVER AN EVEN WARMER OCEAN AND UNDER AN UPPER-LEVEL ENVIRONMENT MORE FAVORABLE FOR STRENGTHENING. THE OFFICIAL FORECAST CALLS FOR EARL TO BECOME A HURRICANE BY SUNDAY AND BECOME AN INTENSE ONE BY DAY FIVE. THIS IS CONSISTENT WITH GUIDANCE WHICH HAS BEEN CONSISTENTLY FORECASTING INTENSIFICATION. ALTHOUGH THE CIRCULATION IS LARGE THE CENTER HAS BEEN DIFFICULT TO LOCATE. IT APPEARS THAT I WAS EITHER SLOW THIS MORNING OR EARL HAS ACCELERATED A LITTLE BIT. THE BEST ESTIMATE OF THE INITIAL MOTION IS 270 DEGREES OR WESTWARD AT 17 KNOTS. EARL IS EXPECTED TO BE STEERED BY THE EASTERLY FLOW SOUTH OF A SUBTROPICAL RIDGE FOR THE NEXT DAY OR SO. THEREAFTER...THE CYCLONE WILL REACH THE WESTERN EDGE OF THE SUBTROPICAL RIDGE AND SHOULD BEGIN TO TURN MORE TO THE WEST-NORTHWEST AND NORTHWEST. I FEEL A LITTLE MORE CERTAIN WITH THE NORTHWESTWARD TURN IN THIS FORECAST SINCE ALL TRACK GUIDANCE UNANIMOUSLY BEGIN TO MOVE EARL ON A MORE WEST-NORTHWESTERLY COURSE BY 48 HOURS. HOWEVER...A DEVIATION TO THE SOUTH OF THE CURRENT FORECAST TRACK COULD BRING EARL INTO THE NORTHERN LEEWARD ISLANDS. WITH THE WEEKEND COMING...RESIDENTS IN THESE ISLANDS SHOULD MONITOR THE PROGRESS OF EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 27/2100Z 15.8N 46.0W 40 KT 12HR VT 28/0600Z 15.9N 48.7W 40 KT 24HR VT 28/1800Z 16.3N 52.2W 50 KT 36HR VT 29/0600Z 17.0N 55.5W 60 KT 48HR VT 29/1800Z 17.5N 58.0W 70 KT 72HR VT 30/1800Z 19.5N 62.2W 80 KT 96HR VT 31/1800Z 23.0N 65.0W 90 KT 120HR VT 01/1800Z 27.0N 68.0W 100 KT $$ FORECASTER AVILA WTNT42 KNHC 280255 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 11 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST FRI AUG 27 2010 SATELLITE IMAGES INDICATE THAT CONVECTION HAS INCREASED IN THE WESTERN SEMICIRCLE OF EARL. BANDING FEATURES ARE BECOMING BETTER DEFINED...AND A THUNDERSTORM CLUSTER IS LOCATED NEAR OR JUST SOUTHWEST OF THE CENTER. SATELLITE ESTIMATES ARE A CONSENSUS 45 KT FROM TAFB/SAB...AND THAT WILL BE THE INITIAL INTENSITY. THE CLOUD PATTERN SUGGESTS THAT NORTHEASTERLY SHEAR HAS INCREASED DURING THE PAST SEVERAL HOURS...AND GLOBAL MODELS SUGGEST THIS SHEAR WILL CONTINUE FOR THE NEXT DAY OR SO. THERE IS ALSO EVIDENCE THAT SOME DRIER AIR IS LURKING NEAR THE CYCLONE. THUS THE INTENSITY FORECAST WILL BE A BIT BELOW MOST OF THE MODEL GUIDANCE FOR THE FIRST 36 HOURS. THEREAFTER...EARL WILL BE MOVING CLOSER TO THE CENTER OF A LARGE UPPER-LEVEL ANTICYCLONE NORTHEAST OF THE LESSER ANTILLES. THIS PATTERN IS QUITE FAVORABLE FOR INTENSIFICATION...ESPECIALLY CONSIDERING THE 29C PLUS SSTS IN THE PATH OF THE HURRICANE. THE GFDL/GFDN RESPOND TO THESE CONDITIONS BY FORECASTING EARL TO BECOME A CATEGORY 4 HURRICANE IN THE LONG-RANGE. WHILE THE NEW NHC FORECAST WILL NOT BE THAT AGGRESSIVE...IT IS INCREASED FROM THE PREVIOUS ONE AND IS CLOSE TO A BLEND OF THE ABOVE DYNAMICAL GUIDANCE AND THE LGEM MODEL. A SERIES OF MICROWAVE PASSES SUGGESTS THE CENTER REMAINS A BIT ELONGATED...THUS CONFIDENCE IN MY INITIAL MOTION OF 275/18 IS LOWER THAN AVERAGE. A STRONG RIDGE BETWEEN EARL AND DANIELLE IS EXPECTED TO KEEP THE TROPICAL STORM MOVING GENERALLY WESTWARD FOR THE NEXT DAY OR SO. AFTER THAT TIME...EARL WILL REACH THE WESTERN PERIPHERY OF THE RIDGE AND IS EXPECTED TO TURN TOWARD THE WEST-NORTHWEST. ALTHOUGH ALL OF THE GUIDANCE SHOWS THE CENTER NORTHEAST OF THE LEEWARD ISLANDS...THERE REMAINS SOME UNCERTAINTY ON HOW CLOSE EARL WILL COME. THE GFS HAS THE STRONGEST RIDGE IN THE GLOBAL MODELS AND MOVES THE CYCLONE CLOSER TO THE LEEWARD ISLANDS THAN MOST OF THE OTHER GUIDANCE. AT THIS POINT...IT IS PRUDENT NOT TO MAKE ANY CHANGES IN THE TRACK FORECAST IN THE FIRST COUPLE OF DAYS... ESPECIALLY SINCE THE CYCLONE HAS MOVED FASTER TOWARDS THE WEST THAN PREVIOUSLY FORECAST. THE NHC FORECAST REMAINS ON THE LEFT EDGE OF THE GUIDANCE ENVELOPE THROUGH THE FIRST THREE DAYS...THEN IS JUST LEFT OF THE MODEL CONSENSUS AT THE END. RESIDENTS IN THE LESSER ANTILLES SHOULD CLOSELY MONITOR THE PROGRESS OF EARL THROUGHOUT THE WEEKEND. WATCHES MAY BE REQUIRED AS EARLY AS SATURDAY MORNING. FORECAST POSITIONS AND MAX WINDS INITIAL 28/0300Z 16.0N 47.9W 45 KT 12HR VT 28/1200Z 16.2N 50.7W 50 KT 24HR VT 29/0000Z 16.6N 54.0W 55 KT 36HR VT 29/1200Z 17.3N 56.8W 65 KT 48HR VT 30/0000Z 18.1N 59.1W 80 KT 72HR VT 31/0000Z 20.5N 63.0W 100 KT 96HR VT 01/0000Z 24.5N 66.0W 110 KT 120HR VT 02/0000Z 29.0N 68.5W 105 KT $$ FORECASTER BLAKE WTNT42 KNHC 280857 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 12 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST SAT AUG 28 2010 EARL HAS BECOME BETTER ORGANIZED THIS MORNING. THE CLOUD PATTERN CONSISTS OF A CENTRAL DENSE OVERCAST WITH CLOUD TOPS TO -80 C AND A LARGE CURVED BAND OVER THE WESTERN SEMICIRCLE OF THE STORM. THE CIRRUS OUTFLOW HAS IMPROVED TO THE SOUTH AND WEST OF THE CENTER BUT REMAINS RESTRICTED OVER THE EASTERN SEMICIRCLE. DVORAK CLASSIFICATIONS ARE 45 KT AND 55 KT FROM TAFB AND SAB... RESPECTIVELY. ON THIS BASIS...THE INITIAL INTENSITY IS INCREASED TO 50 KT FOR THIS ADVISORY. A 0413 UTC TRMM OVERPASS INDICATED THAT THE LOW-LEVEL CENTER OF EARL WAS LOCATED A LITTLE TO THE SOUTH OF THE PREVIOUS ESTIMATES. USING A COMBINATION OF THIS OVERPASS AND SATELLITE FIXES YIELDS AN INITIAL MOTION OF 270/18. A MID-LEVEL RIDGE LOCATED OVER THE SUBTROPICAL CENTRAL ATLANTIC IS EXPECTED TO KEEP EARL ON A RATHER QUICK WESTWARD TO WEST-NORTHWESTWARD COURSE FOR THE NEXT DAY OR TWO. THEREAFTER...THE CYCLONE IS EXPECTED TO NEAR A BREAK IN THE RIDGE...AND THAT SHOULD CAUSE A TURN TO THE NORTHWEST. WHILE THE GLOBAL MODELS AGREE ON THE GENERAL EVOLUTION OF THE LARGE SCALE PATTERN...THERE ARE CONSIDERABLE DIFFERENCES ON THE DETAILS OF THE TIMING...LOCATION AND SHARPNESS OF THE TURN. THE OFFICIAL FORECAST IS NUDGED A LITTLE TO THE LEFT OF THE PREVIOUS ONE TO ACCOUNT FOR THE INITIAL POSITION AND MOTION AND TRENDS TOWARD THE MULTI-MODEL CONSENSUS. ALL OF THE INTENSITY GUIDANCE SHOWS ADDITIONAL INTENSIFICATION DURING THE NEXT FEW DAYS...AS EARL MOVES OVER EVEN WARMER WATERS AND INTO A MORE FAVORABLE UPPER-LEVEL WIND ENVIRONMENT. THE OFFICIAL FORECAST IS ADJUSTED UPWARD FOR THE FIRST COUPLE OF DAYS AND NOW BRINGS EARL TO HURRICANE STRENGTH IN 24 HOURS AND TO MAJOR HURRICANE STATUS IN 3 DAYS. BEYOND 72 HOURS...SOUTHWESTERLY SHEAR IS EXPECTED TO INCREASE...WHICH SHOULD HALT INTENSIFICATION AND POSSIBLY INDUCE GRADUAL WEAKENING. THIS IS REFLECTED IN THE OFFICIAL FORECAST...WHICH IS IN BEST AGREEMENT WITH THE INTENSITY MODEL CONSENSUS. THE FORECAST NECESSITATES THE ISSUANCE OF TROPICAL STORM WATCHES FOR PORTIONS OF THE NORTHERN LEEWARD ISLANDS. FORECAST POSITIONS AND MAX WINDS INITIAL 28/0900Z 15.7N 50.1W 50 KT 12HR VT 28/1800Z 16.0N 52.7W 60 KT 24HR VT 29/0600Z 16.5N 55.7W 65 KT 36HR VT 29/1800Z 17.2N 58.3W 75 KT 48HR VT 30/0600Z 18.2N 60.5W 85 KT 72HR VT 31/0600Z 20.8N 64.2W 100 KT 96HR VT 01/0600Z 24.5N 67.5W 110 KT 120HR VT 02/0600Z 29.5N 69.5W 100 KT $$ FORECASTER CANGIALOSI/BRENNAN WTNT42 KNHC 281436 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST SAT AUG 28 2010 ALTHOUGH THE CIRCULATION CONTINUES TO BE LARGE AND VIGOROUS AND THE AMOUNT OF DEEP CONVECTION HAS INCREASED SINCE YESTERDAY...VISIBLE IMAGES INDICATE THAT CENTER HAS BECOME EXPOSED AND IS LOCATED ON THE NORTHWESTERN SIDE OF THE DEEP CONVECTION. THIS HAS RESULTED FROM SOME MODEST NORTHERLY SHEAR CAUSED BY THE OUTFLOW OF LARGER HURRICANE DANIELLE. ALTHOUGH THE CYCLONE IS LESS ORGANIZED THAN EARLIER TODAY...T-NUMBERS HAVE NOT CHANGED MUCH AND THE INITIAL INTENSITY IS KEPT AT 50 KNOTS...BUT THE INTENSITY COULD BE LOWER. THE CURRENT NORTHERLY SHEAR IS EXPECTED TO ABATE SOON AS DANIELLE MOVES NORTHWARD AND...IN FACT...MOST OF THE GLOBAL MODELS SHOW THE UPPER-LEVEL FLOW BECOMING MORE FAVORABLE FOR INTENSIFICATION BY SUNDAY. THIS FLOW PATTERN...IN COMBINATION WITH A WARM OCEAN ALONG THE TRACK...WOULD RESULT IN INTENSIFICATION. EARL IS FORECAST TO BECOME A HURRICANE BY SUNDAY WITH A STEADY INTENSIFICATION THEREAFTER. EARL IS MOVING TOWARD THE WEST OR 275 DEGREES AT ABOUT 16 OR 17 KNOTS STEERED BY THE FLOW TO THE SOUTH OF A SUBTROPICAL RIDGE. HOWEVER...IN A DAY OR SO...EARL WILL BE APPROACHING THE WESTERN EDGE OF THE RIDGE AND THE CYCLONE SHOULD BEGIN TO TURN MORE TO THE WEST-NORTHWEST AND NORTHWEST. THE TRACK MODELS DIVERGE BEYOND 48 HOURS BUT ONCE AGAIN...THE OFFICIAL FORECAST AND THE GUIDANCE ENVELOPE HAVE SHIFTED A LITTLE BIT SOUTHWARD AND WESTWARD. NEVERTHELESS...THE EXPECTED STEERING PATTERN STILL FAVORS A GRADUAL TURN TO THE WEST-NORTHWEST DURING THE NEXT DAY OR TWO. AT THIS TIME...IT IS NOT NECESSARY TO CHANGE THE TROPICAL STORM WATCH FOR THE NORTHERN LEEWARD ISLANDS BUT A DEVIATION OF THE TRACK TO THE WEST WOULD REQUIRE ADDITIONAL WATCHES OR WARNINGS. A NOAA-P3 AIRCRAFT RESEARCH MISSION WILL PROBABLY CHECK THE SYSTEM LATER TODAY WHILE A NOAA GULFSTREAM JET SAMPLES THE ENVIRONMENT. THE FIRST AIR FORCE RECONNAISSANCE AIRCRAFT INTO EARL IS SCHEDULED FOR EARLY SUNDAY. FORECAST POSITIONS AND MAX WINDS INITIAL 28/1500Z 16.0N 51.8W 50 KT 12HR VT 29/0000Z 16.1N 54.3W 55 KT 24HR VT 29/1200Z 17.0N 57.5W 65 KT 36HR VT 30/0000Z 17.8N 60.0W 75 KT 48HR VT 30/1200Z 18.7N 62.0W 85 KT 72HR VT 31/1200Z 21.5N 66.0W 95 KT 96HR VT 01/1200Z 25.0N 69.0W 100 KT 120HR VT 02/1200Z 30.0N 71.0W 100 KT $$ FORECASTER AVILA WTNT42 KNHC 282042 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 14 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST SAT AUG 28 2010 THE CENTER BECAME EXPOSED EARLIER TODAY BUT IT APPEARS THAT THE SHEAR HAS BEGUN TO RELAX AND THE CENTER IS NOW TUCKED INTO THE CONVECTION ONCE AGAIN. EARL HAS MAINTAINED A LARGE VIGOROUS CIRCULATION AND ITS UPPER-LEVEL OUTFLOW IS MAINLY TO THE SOUTH AND WEST DUE TO THE STILL PREVAILING NORTHERLY SHEAR. T-NUMBERS THIS AFTERNOON SUPPORT AN INITIAL INTENSITY OF 50 KNOTS. SINCE THE NORTHERLY SHEAR IS EXPECTED TO ABATE...AND BECAUSE THERE IS PLENTY OF VERY WARM WATERS ALONG THE TRACK...THE OFFICIAL FORECAST CALLS FOR INTENSIFICATION WITH A SIMILAR TREND INDICATED BY THE LGEM MODEL...AND MAKES EARL AN INTENSE HURRICANE IN ABOUT 3 DAYS. EARL HAS INCREASED ITS FORWARD SPEED AND IS NOW MOVING TOWARD THE WEST OR 280 DEGREES AT 20 KNOTS. HOWEVER SOON...THE CYCLONE WILL BE APPROACHING THE WESTERN EDGE OF THE SUBTROPICAL RIDGE AND BEGIN TO TURN MORE TO THE WEST-NORTHWEST WITH A DECREASE IN FORWARD SPEED. THIS IS CONSISTENT WITH THE TRACK MODELS WHICH ARE IN GOOD AGREEMENT. DUE TO AN INITIAL MOTION WHICH HAS BEEN A LITTLE MORE TO THE WEST THAN INDICATED BY TRACK MODELS...THE OFFICIAL FORECAST LIES ON THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE...PRIMARILY DURING THE NEXT FIRST 24 TO 36 HOURS. GUIDANCE ALSO INDICATES A SIGNIFICANT DECREASE IN FORWARD SPEED AS EARL MOVES NEAR OR OVER THE NORTHERN LEEWARD ISLANDS...AND SO DOES THE OFFICIAL FORECAST. A NOAA-P3 AIRCRAFT RESEARCH MISSION IS EN ROUTE TO CHECK EARL AND WILL LIKELY GIVE US A BETTER MEASUREMENT OF THE INTENSITY AND THE WIND RADII. FORECAST POSITIONS AND MAX WINDS INITIAL 28/2100Z 16.5N 54.2W 50 KT 12HR VT 29/0600Z 17.0N 57.0W 55 KT 24HR VT 29/1800Z 17.5N 59.5W 65 KT 36HR VT 30/0600Z 18.3N 61.8W 75 KT 48HR VT 30/1800Z 19.0N 63.5W 85 KT 72HR VT 31/1800Z 21.0N 67.0W 100 KT 96HR VT 01/1800Z 25.0N 70.5W 100 KT 120HR VT 02/1800Z 30.5N 72.5W 100 KT $$ FORECASTER AVILA WTNT42 KNHC 290314 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST SAT AUG 28 2010 A NOAA HURRICANE HUNTER FLYING A RESEARCH MISSION INTO EARL REPORTED FLIGHT-LEVEL AND SFMR WINDS SUPPORTING A INITIAL INTENSITY OF 55 KT. THIS IS IN GOOD AGREEMENT WITH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB OF 55 KT...AND A CIMSS AMSU ESTIMATE OF 56 KT. THE AIRCRAFT DATA SUGGEST THE CENTRAL PRESSURE IS NEAR 989 MB. WHILE EARL IS STILL SHOWING SIGNS OF NORTHEASTERLY VERTICAL WIND SHEAR...THE CONVECTION HAS INCREASED IN BOTH COVERAGE AND ORGANIZATION DURING THE PAST SEVERAL HOURS. THE INITIAL MOTION IS 280/17. EARL IS APPROACHING THE END OF A LOW/MID-LEVEL RIDGE SEPARATING IT FROM HURRICANE DANIELLE...WITH WATER VAPOR IMAGERY SHOWING AN UPPER-LEVEL TROUGH JUST NORTH OF CUBA AND HISPANIOLA. THE LARGE-SCALE MODELS FORECAST A LOW-LEVEL RIDGE TO BUILD TO THE NORTH OF EARL DURING THE NEXT 48-72 HR... WHILE THE TROUGH REMAINS NEARLY STATIONARY AND POSSIBLY STRENGTHENS. THE LOW-LEVEL RIDGE WILL STEER EARL GENERALLY TOWARD THE WEST-NORTHWEST OR WEST WITH SOME DECREASE IN FORWARD SPEED...WITH THE UPPER TROUGH TRYING TO TURN IT NORTHWARD AS IT APPROACHES. OVERALL...THIS PATTERN EVOLUTION SHOULD CAUSE EARL TO MOVE GENERALLY WEST-NORTHWESTWARD FOR 48 HR OR SO...FOLLOWED BY A GRADUAL TURN TO THE NORTHWEST AND NORTH AS THE TROUGH EXERTS A GREATER INFLUENCE. THE NEW FORECAST TRACK IS SHIFTED A LITTLE SOUTH OF THE PREVIOUS TRACK DURING THE FIRST 12 HR BASED ON THE INITIAL POSITION AND MOTION. AFTER THAT...IT LIES A LITTLE TO LEFT OF THE CENTER OF THE GUIDANCE ENVELOPE BETWEEN THE CONSENSUS MODELS AND THE GFDL. THE NEW TRACK IS SIMILAR TO...BUT A LITTLE SOUTH OF...THE PREVIOUS TRACK. THE CURRENT NORTHEASTERLY SHEAR SHOULD GRADUALLY DIMINISH OVER THE NEXT 24 HR AND ALLOW EARL TO STRENGTHEN. THE INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT EARL SHOULD BECOME A MAJOR HURRICANE BY 72 HR...IF NOT SOONER...AND THIS IS REFLECTED IN THE NHC FORECAST. THE INTENSITY FORECAST IS MORE PROBLEMATIC AFTER 72 HR...AS THERE ARE DISAGREEMENTS IN THE LARGE-SCALE MODELS ON HOW MUCH SHEAR EARL WILL ENCOUNTER AS IT APPROACHES THE UPPER-LEVEL TROUGH. THE GFS AND ECMWF FORECAST LIGHT ENOUGH SHEAR TO ALLOW EARL TO MAINTAIN ITS STRENGTH...WHILE THE UKMET FORECASTS STRONG ENOUGH UPPER-LEVEL WINDS TO CAUSE EARL TO SHEAR APART. AT THIS TIME...THE INTENSITY FORECAST COMPROMISES BETWEEN THESE EXTREMES WITH SLOW WEAKENING AFTER 96 HR. THE INITIAL AND FORECAST WIND RADII HAVE BEEN SIGNIFICANTLY REVISED BASED ON THE AIRCRAFT DATA. THE NEW FORECAST TRACK REQUIRES HURRICANE WARNINGS TO BE ISSUED FOR PORTIONS OF THE NORTHERN LEEWARD ISLANDS AT THIS TIME. ADDITIONAL WARNINGS WILL BE REQUIRED ON SUNDAY. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0300Z 16.6N 55.4W 55 KT 12HR VT 29/1200Z 17.0N 57.5W 60 KT 24HR VT 30/0000Z 17.5N 60.0W 70 KT 36HR VT 30/1200Z 18.1N 62.0W 80 KT 48HR VT 31/0000Z 19.0N 63.9W 90 KT 72HR VT 01/0000Z 22.0N 68.0W 100 KT 96HR VT 02/0000Z 25.0N 71.0W 105 KT 120HR VT 03/0000Z 31.0N 72.5W 100 KT $$ FORECASTER BEVEN WTNT42 KNHC 290842 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST SUN AUG 29 2010 DEEP CONVECTION HAS DECREASED NEAR THE ESTIMATED CENTER OF EARL OVER THE PAST FEW HOURS...AND THE COLDEST CLOUD TOPS ARE NOW LOCATED IN A LARGE BAND TO THE SOUTHWEST OF THE CENTER. EARL APPEARS TO BE EXPERIENCING SOME NORTHERLY SHEAR ASSOCIATED WITH THE OUTFLOW FROM HURRICANE DANIELLE...AND THE OUTFLOW IS RESTRICTED IN THE NORTHERN SEMICIRCLE. THE INITIAL INTENSITY IS HELD AT 55 KT IN AGREEMENT WITH DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB. THE SHEAR WILL BE DECREASING SOON AS DANIELLE CONTINUES MOVING AWAY...AND EARL SHOULD BE IN AN ENVIRONMENT THAT WILL SUPPORT STEADY STRENGTHENING THROUGH THE PERIOD. MOST OF THE GUIDANCE SUGGESTS EARL WILL BECOME A HURRICANE IN 12 TO 24 HOURS ...AND REACH MAJOR HURRICANE STRENGTH IN 72 TO 96 HOURS. THE NHC INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE AND CLOSE TO THE ICON CONSENSUS. THE CENTER HAS BEEN DIFFICULT TO LOCATE ON INFRARED IMAGERY OVERNIGHT...SO THE INITIAL MOTION ESTIMATE OF 280/16 IS LARGELY BASED ON CONTINUITY. EARL WILL SOON REACH THE SOUTHWESTERN EDGE OF THE SUBTROPICAL RIDGE CENTERED ALONG 25N...WHICH SHOULD RESULT IN A TURN TOWARD THE WEST-NORTHWEST AND A DECREASE IN FORWARD SPEED OVER THE NEXT 24 TO 36 HOURS. BEYOND THAT TIME...A BREAK DEVELOPS IN THE SUBTROPICAL RIDGE ALONG 65 TO 70W AS THE LARGE UPPER TROUGH INTERACTING WITH DANIELLE LIFTS OUT TO THE NORTHEAST. THE TRACK GUIDANCE IS IN GOOD AGREEMENT IN SHOWING EARL TURNING NORTHWESTWARD INTO THIS WEAKNESS IN 2 OR 3 DAYS...AND THEN ACCELERATING NORTHWARD...ALTHOUGH THERE IS SOME SPREAD IN THE FORWARD SPEED AT DAYS 4 AND 5. THE OFFICIAL NHC FORECAST IS SIMILAR TO THE PREVIOUS PACKAGE THROUGH THE FIRST 48 HOURS...AND IS FASTER LATE IN THE PERIOD IN AGREEMENT WITH THE MULTI-MODEL CONSENSUS. ON THE FORECAST TRACK...EARL WILL MOVE VERY CLOSE TO THE NORTHERN LEEWARD ISLANDS IN THE NEXT 24 TO 36 HOURS. CONDITIONS WILL BEGIN TO DETERIORATE IN THOSE AREAS LATER TODAY AND TONIGHT. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0900Z 16.9N 56.9W 55 KT 12HR VT 29/1800Z 17.3N 59.1W 65 KT 24HR VT 30/0600Z 17.9N 61.4W 70 KT 36HR VT 30/1800Z 18.7N 63.6W 80 KT 48HR VT 31/0600Z 19.9N 65.4W 90 KT 72HR VT 01/0600Z 23.5N 69.0W 100 KT 96HR VT 02/0600Z 29.0N 72.0W 105 KT 120HR VT 03/0600Z 34.5N 72.0W 105 KT $$ FORECASTER BRENNAN WTNT42 KNHC 290314 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST SAT AUG 28 2010 A NOAA HURRICANE HUNTER FLYING A RESEARCH MISSION INTO EARL REPORTED FLIGHT-LEVEL AND SFMR WINDS SUPPORTING A INITIAL INTENSITY OF 55 KT. THIS IS IN GOOD AGREEMENT WITH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB OF 55 KT...AND A CIMSS AMSU ESTIMATE OF 56 KT. THE AIRCRAFT DATA SUGGEST THE CENTRAL PRESSURE IS NEAR 989 MB. WHILE EARL IS STILL SHOWING SIGNS OF NORTHEASTERLY VERTICAL WIND SHEAR...THE CONVECTION HAS INCREASED IN BOTH COVERAGE AND ORGANIZATION DURING THE PAST SEVERAL HOURS. THE INITIAL MOTION IS 280/17. EARL IS APPROACHING THE END OF A LOW/MID-LEVEL RIDGE SEPARATING IT FROM HURRICANE DANIELLE...WITH WATER VAPOR IMAGERY SHOWING AN UPPER-LEVEL TROUGH JUST NORTH OF CUBA AND HISPANIOLA. THE LARGE-SCALE MODELS FORECAST A LOW-LEVEL RIDGE TO BUILD TO THE NORTH OF EARL DURING THE NEXT 48-72 HR... WHILE THE TROUGH REMAINS NEARLY STATIONARY AND POSSIBLY STRENGTHENS. THE LOW-LEVEL RIDGE WILL STEER EARL GENERALLY TOWARD THE WEST-NORTHWEST OR WEST WITH SOME DECREASE IN FORWARD SPEED...WITH THE UPPER TROUGH TRYING TO TURN IT NORTHWARD AS IT APPROACHES. OVERALL...THIS PATTERN EVOLUTION SHOULD CAUSE EARL TO MOVE GENERALLY WEST-NORTHWESTWARD FOR 48 HR OR SO...FOLLOWED BY A GRADUAL TURN TO THE NORTHWEST AND NORTH AS THE TROUGH EXERTS A GREATER INFLUENCE. THE NEW FORECAST TRACK IS SHIFTED A LITTLE SOUTH OF THE PREVIOUS TRACK DURING THE FIRST 12 HR BASED ON THE INITIAL POSITION AND MOTION. AFTER THAT...IT LIES A LITTLE TO LEFT OF THE CENTER OF THE GUIDANCE ENVELOPE BETWEEN THE CONSENSUS MODELS AND THE GFDL. THE NEW TRACK IS SIMILAR TO...BUT A LITTLE SOUTH OF...THE PREVIOUS TRACK. THE CURRENT NORTHEASTERLY SHEAR SHOULD GRADUALLY DIMINISH OVER THE NEXT 24 HR AND ALLOW EARL TO STRENGTHEN. THE INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT EARL SHOULD BECOME A MAJOR HURRICANE BY 72 HR...IF NOT SOONER...AND THIS IS REFLECTED IN THE NHC FORECAST. THE INTENSITY FORECAST IS MORE PROBLEMATIC AFTER 72 HR...AS THERE ARE DISAGREEMENTS IN THE LARGE-SCALE MODELS ON HOW MUCH SHEAR EARL WILL ENCOUNTER AS IT APPROACHES THE UPPER-LEVEL TROUGH. THE GFS AND ECMWF FORECAST LIGHT ENOUGH SHEAR TO ALLOW EARL TO MAINTAIN ITS STRENGTH...WHILE THE UKMET FORECASTS STRONG ENOUGH UPPER-LEVEL WINDS TO CAUSE EARL TO SHEAR APART. AT THIS TIME...THE INTENSITY FORECAST COMPROMISES BETWEEN THESE EXTREMES WITH SLOW WEAKENING AFTER 96 HR. THE INITIAL AND FORECAST WIND RADII HAVE BEEN SIGNIFICANTLY REVISED BASED ON THE AIRCRAFT DATA. THE NEW FORECAST TRACK REQUIRES HURRICANE WARNINGS TO BE ISSUED FOR PORTIONS OF THE NORTHERN LEEWARD ISLANDS AT THIS TIME. ADDITIONAL WARNINGS WILL BE REQUIRED ON SUNDAY. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0300Z 16.6N 55.4W 55 KT 12HR VT 29/1200Z 17.0N 57.5W 60 KT 24HR VT 30/0000Z 17.5N 60.0W 70 KT 36HR VT 30/1200Z 18.1N 62.0W 80 KT 48HR VT 31/0000Z 19.0N 63.9W 90 KT 72HR VT 01/0000Z 22.0N 68.0W 100 KT 96HR VT 02/0000Z 25.0N 71.0W 105 KT 120HR VT 03/0000Z 31.0N 72.5W 100 KT $$ FORECASTER BEVEN WTNT42 KNHC 290842 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST SUN AUG 29 2010 DEEP CONVECTION HAS DECREASED NEAR THE ESTIMATED CENTER OF EARL OVER THE PAST FEW HOURS...AND THE COLDEST CLOUD TOPS ARE NOW LOCATED IN A LARGE BAND TO THE SOUTHWEST OF THE CENTER. EARL APPEARS TO BE EXPERIENCING SOME NORTHERLY SHEAR ASSOCIATED WITH THE OUTFLOW FROM HURRICANE DANIELLE...AND THE OUTFLOW IS RESTRICTED IN THE NORTHERN SEMICIRCLE. THE INITIAL INTENSITY IS HELD AT 55 KT IN AGREEMENT WITH DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB. THE SHEAR WILL BE DECREASING SOON AS DANIELLE CONTINUES MOVING AWAY...AND EARL SHOULD BE IN AN ENVIRONMENT THAT WILL SUPPORT STEADY STRENGTHENING THROUGH THE PERIOD. MOST OF THE GUIDANCE SUGGESTS EARL WILL BECOME A HURRICANE IN 12 TO 24 HOURS ...AND REACH MAJOR HURRICANE STRENGTH IN 72 TO 96 HOURS. THE NHC INTENSITY FORECAST IS SIMILAR TO THE PREVIOUS ONE AND CLOSE TO THE ICON CONSENSUS. THE CENTER HAS BEEN DIFFICULT TO LOCATE ON INFRARED IMAGERY OVERNIGHT...SO THE INITIAL MOTION ESTIMATE OF 280/16 IS LARGELY BASED ON CONTINUITY. EARL WILL SOON REACH THE SOUTHWESTERN EDGE OF THE SUBTROPICAL RIDGE CENTERED ALONG 25N...WHICH SHOULD RESULT IN A TURN TOWARD THE WEST-NORTHWEST AND A DECREASE IN FORWARD SPEED OVER THE NEXT 24 TO 36 HOURS. BEYOND THAT TIME...A BREAK DEVELOPS IN THE SUBTROPICAL RIDGE ALONG 65 TO 70W AS THE LARGE UPPER TROUGH INTERACTING WITH DANIELLE LIFTS OUT TO THE NORTHEAST. THE TRACK GUIDANCE IS IN GOOD AGREEMENT IN SHOWING EARL TURNING NORTHWESTWARD INTO THIS WEAKNESS IN 2 OR 3 DAYS...AND THEN ACCELERATING NORTHWARD...ALTHOUGH THERE IS SOME SPREAD IN THE FORWARD SPEED AT DAYS 4 AND 5. THE OFFICIAL NHC FORECAST IS SIMILAR TO THE PREVIOUS PACKAGE THROUGH THE FIRST 48 HOURS...AND IS FASTER LATE IN THE PERIOD IN AGREEMENT WITH THE MULTI-MODEL CONSENSUS. ON THE FORECAST TRACK...EARL WILL MOVE VERY CLOSE TO THE NORTHERN LEEWARD ISLANDS IN THE NEXT 24 TO 36 HOURS. CONDITIONS WILL BEGIN TO DETERIORATE IN THOSE AREAS LATER TODAY AND TONIGHT. FORECAST POSITIONS AND MAX WINDS INITIAL 29/0900Z 16.9N 56.9W 55 KT 12HR VT 29/1800Z 17.3N 59.1W 65 KT 24HR VT 30/0600Z 17.9N 61.4W 70 KT 36HR VT 30/1800Z 18.7N 63.6W 80 KT 48HR VT 31/0600Z 19.9N 65.4W 90 KT 72HR VT 01/0600Z 23.5N 69.0W 100 KT 96HR VT 02/0600Z 29.0N 72.0W 105 KT 120HR VT 03/0600Z 34.5N 72.0W 105 KT $$ FORECASTER BRENNAN WTNT42 KNHC 291457 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST SUN AUG 29 2010 EARL HAS BECOME MUCH BETTER ORGANIZED IN SATELLITE IMAGERY WITH SEVERAL BANDS OF THUNDERSTORMS WRAPPING AROUND THE CENTER AND A DEVELOPING CDO. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT FOUND 850 MB FLIGHT-LEVEL WINDS OF 81 KT AND SFMR SURFACE WINDS OF 64 KT EARLIER THIS MORNING. THESE MEASUREMENTS SUPPORTED THE EARLIER UPGRADE TO HURRICANE STATUS. NORTHEASTERLY SHEAR SHOULD CONTINUE TO DECREASE TODAY...AND THE UPPER-LEVEL ENVIRONMENT APPEARS QUITE FAVORABLE FOR INTENSIFICATION DURING THE NEXT FEW DAYS. THE SHIPS...LGEM...AND GFDL MODELS SUPPORT STEADY STRENGTHENING...AND THE OFFICIAL FORECAST IS NEAR THE HIGH END OF THE GUIDANCE THROUGH 36 HOURS...PREDICTING THAT EARL WILL ATTAIN MAJOR HURRICANE DURING THAT TIME. THEREAFTER... THE NHC FORECAST IS CLOSE TO A BLEND OF THE MORE AGGRESSIVE GFDL AND THE LOWER SHIPS/LGEM MODELS. THE HURRICANE IS STILL MOVING WESTWARD OR 280/15 KT. EARL IS EXPECTED TO TURN WEST-NORTHWESTWARD AND SLOW DOWN AS IT APPROACHES THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT DAY OR SO. THE HURRICANE IS FORECAST TO TURN NORTHWESTWARD IN 2-3 DAYS AS IT ROUNDS THE RIDGE. LATE IN THE FORECAST PERIOD...A TROUGH IS FORECAST TO MOVE ACROSS THE GREAT LAKES....WHICH SHOULD RESULT IN A NORTHWARD MOTION. THE TRACK GUIDANCE IS IN GOOD AGREEMENT...BUT THE GLOBAL MODELS ARE MUCH FASTER THAN THE REGIONAL HURRICANE MODELS AT DAYS 4 AND 5. THE NHC TRACK IS ALONG THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE FOR THE FIRST 36 HOURS AND LEANS TOWARD THE FASTER SOLUTION OF THE GLOBAL MODELS AT DAYS 4 AND 5. PERSONS IN THE LEEWARD ISLANDS SHOULD REMEMBER THAT THE HURRICANE IS NOT A POINT SINCE HAZARDS EXTEND WELL AWAY FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INITIAL 29/1500Z 17.2N 58.4W 65 KT 12HR VT 30/0000Z 17.6N 60.4W 75 KT 24HR VT 30/1200Z 18.5N 62.7W 90 KT 36HR VT 31/0000Z 19.6N 64.5W 100 KT 48HR VT 31/1200Z 21.1N 66.3W 105 KT 72HR VT 01/1200Z 25.2N 69.8W 110 KT 96HR VT 02/1200Z 31.0N 72.0W 110 KT 120HR VT 03/1200Z 37.0N 71.5W 100 KT $$ FORECASTER BROWN/BERG WTNT42 KNHC 292052 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST SUN AUG 29 2010 THE SATELLITE APPEARANCE OF EARL HAS CONTINUED TO IMPROVE THROUGHOUT THE DAY. SEVERAL CURVED BANDS OF THUNDERSTORMS ARE SEEN SURROUNDING A CENTRAL DENSE OVERCAST FEATURE. THERE ARE NO HINTS OF AN EYE IN VISIBLE IMAGERY...HOWEVER AN EYE IS APPARENT IN RECENT RADAR IMAGERY FROM GUADELOUPE AND WAS ALSO REPORTED BY THE AIRCRAFT A FEW HOURS AGO. ALTHOUGH THE PLANE DID NOT FIND HIGHER FLIGHT-LEVEL OR SFMR WINDS THAN IT DID THIS MORNING...THE MINIMUM PRESSURE REPORTED WAS LOWER ON EACH SUCCESSIVE FIX AND WAS DOWN TO 978 MB. BASED ON SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY ESTIMATES... AND THE INCREASED ORGANIZATION ON SATELLITE IMAGES...THE ADVISORY INTENSITY HAS BEEN INCREASED TO 75 KT. A NOAA P-3 AIRCRAFT ON A RESEARCH MISSION SHOULD BE IN EARL SHORTLY...FOLLOWED BY THE NEXT AIR FORCE C-130 MISSION BETWEEN 0000 AND 0600 UTC. THE CENTER FIXES FROM THE AIRCRAFT FLIGHT TODAY YIELD AN INITIAL MOTION OF ABOUT 285/12...A LITTLE SLOWER THAN BEFORE. THE FORECAST REASONING REMAINS UNCHANGED FROM THE PREVIOUS ADVISORY. EARL IS EXPECTED TO BE STEERED AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT COUPLE OF DAYS. THE HURRICANE SHOULD TURN NORTHWESTWARD IN 36-48 HOURS. EARL IS FORECAST TO TURN NORTHWARD...THEN NORTHEASTWARD AHEAD OF A TROUGH THAT MOVES INTO GREAT LAKES REGION IN 4-5 DAYS. THE TRACK GUIDANCE GENERALLY AGREES WITH THIS SCENARIO...BUT THERE ARE SOME LARGE DIFFERENCES IN THE FORWARD SPEED OF EARL AT DAYS 4 AND 5. THE GLOBAL MODELS REMAIN FASTER THAN THE GFDL/HWRF AND THE OFFICIAL CONTINUES TO BE FASTER THAN THE DYNAMICAL MODEL CONSENSUS AFTER 72 HOURS. THE GLOBAL MODELS SHOW A RATHER FAVORABLE UPPER-LEVEL ENVIRONMENT FOR STRENGTHENING DURING THE NEXT COUPLE OF DAYS AS AN UPPER-LEVEL ANTICYCLONE BUILDS OVER THE SYSTEM. THE SHIPS...LGEM...AND GFDL MODELS SHOW EARL REACHING MAJOR HURRICANE STRENGTH IN A DAY OR SO AND THE OFFICIAL FORECAST FOLLOWS SUIT. LATE IN THE FORECAST PERIOD...THE HURRICANE IS EXPECTED TO BEGIN TO WEAKEN AS IT MOVES OVER COOLER SSTS AND INTO AN AREA OF INCREASING SOUTHWESTERLY SHEAR. FORECAST POSITIONS AND MAX WINDS INITIAL 29/2100Z 17.6N 59.5W 75 KT 12HR VT 30/0600Z 18.0N 61.3W 90 KT 24HR VT 30/1800Z 18.9N 63.3W 100 KT 36HR VT 31/0600Z 20.3N 65.1W 110 KT 48HR VT 31/1800Z 22.1N 66.9W 115 KT 72HR VT 01/1800Z 27.3N 70.2W 115 KT 96HR VT 02/1800Z 33.5N 71.5W 105 KT 120HR VT 03/1800Z 40.0N 68.0W 90 KT $$ FORECASTER BROWN/BERG WTNT42 KNHC 300236 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 19 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST SUN AUG 29 2010 EARL HAS STRENGTHENED OVER THE PAST FEW HOURS. THE AIR FORCE HURRICANE HUNTERS RECENTLY FOUND AN SFMR-MEASURED SURFACE WIND SPEED OF 83 KT JUST SOUTHEAST OF THE CENTER. MAXIMUM FLIGHT-LEVEL WINDS FROM THE AIRCRAFT WERE 93 KT...WHICH ADJUSTS TO 84 KT AT THE SURFACE USING THE STANDARD REDUCTION FACTOR. BASED ON THESE OBSERVATIONS...THE CURRENT INTENSITY IS SET TO 85 KT. IMAGES FROM THE GUADELOUPE AND ST. MARTIN RADARS SHOW A BANDING-TYPE EYE ABOUT 30 N MI IN DIAMETER WHILE THE RECONNAISSANCE OBSERVATIONS INDICATED THAT THE EYE WAS OPEN OVER THE NORTHWEST QUADRANT. WATER VAPOR IMAGERY SHOWS THAT THE UPPER-LEVEL OUTFLOW IS BEING IMPEDED OVER THE NORTHEAST QUADRANT...BUT IS WELL ESTABLISHED OVER THE REMAINDER OF THE CIRCULATION. A BROAD UPPER-LEVEL TROUGH IS CURRENTLY SITUATED TO THE NORTHWEST OF EARL. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT THIS TROUGH WILL SHIFT WESTWARD AND WEAKEN. THIS SHOULD CREATE A ENVIRONMENT CONDUCIVE FOR INTENSIFICATION AND THE OFFICIAL FORECAST...LIKE THE PREVIOUS ONE...SHOWS EARL BECOMING A MAJOR HURRICANE OVER THE NEXT DAY OR SO. THE NHC WIND SPEED FORECAST IS ABOVE THE INTENSITY MODEL CONSENSUS BUT BELOW THE LATEST GFDL HURRICANE MODEL GUIDANCE. INITIAL MOTION...285/13...IS ABOUT THE SAME AS IN THE PREVIOUS ADVISORY. A GRADUAL TURN TO THE NORTHWEST IS LIKELY TO TAKE PLACE IN 24 TO 36 HOURS AS THE HURRICANE ENCOUNTERS THE WESTERN PERIPHERY OF A MID-TROPOSPHERIC ANTICYCLONE. BY DAYS 3 TO 4...THE HEADING AND FORWARD SPEED OF EARL ARE DEPENDENT ON THE DETAILS OF THE EVOLUTION OF A 500 MB TROUGH MOVING THROUGH THE GREAT LAKES. THE GFS AND ECMWF SHOW THIS TROUGH AMPLIFYING MORE THAN THE OTHER DYNAMICAL MODELS AND MOVE EARL SIGNIFICANTLY FASTER TO THE NORTH-NORTHEAST WITH A SHARPER EASTWARD TURN THAN THE OTHER GUIDANCE. THE OFFICIAL TRACK FORECAST IS NOT QUITE AS FAST AS THE GFS AND ECMWF...BUT IS CLOSE TO THE MULTI-MODEL CONSENSUS. THE FORECAST WIND RADII HAVE BEEN EXPANDED A LITTLE BASED ON DYNAMICAL...MAINLY GLOBAL MODEL...GUIDANCE. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0300Z 17.9N 61.1W 85 KT 12HR VT 30/1200Z 18.5N 62.7W 90 KT 24HR VT 31/0000Z 19.6N 64.6W 100 KT 36HR VT 31/1200Z 21.1N 66.4W 110 KT 48HR VT 01/0000Z 22.8N 68.2W 115 KT 72HR VT 02/0000Z 27.5N 71.5W 115 KT 96HR VT 03/0000Z 34.0N 72.0W 100 KT 120HR VT 04/0000Z 40.0N 67.0W 85 KT $$ FORECASTER PASCH WTNT42 KNHC 300845 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST MON AUG 30 2010 SINCE THE AIRCRAFT DEPARTED JUST PRIOR TO 0600 UTC...AN EYE HAS BEEN OCCASIONALLY APPARENT IN INFRARED IMAGERY...AND HAS BECOME BETTER DEFINED WITH A DIAMETER OF ABOUT 25 NM ON THE ST. MAARTEN RADAR. THE AIRCRAFT MEASURED A FLIGHT LEVEL MAXIMUM WIND OF 97 KT AT 0510 UTC...AND 0600 UTC DVORAK INTENSITY ESTIMATES WERE 90 KT FROM TAFB AND SAB. BASED ON THESE DATA...THE INITIAL INTENSITY IS SET TO 90 KT FOR THIS ADVISORY. THE OUTFLOW IS IMPROVING IN THE NORTHEASTERN QUADRANT AND IS GOOD ELSEWHERE...AND THE OVERALL ENVIRONMENT SHOULD SUPPORT STEADY INTENSIFICATION THROUGH THE NEXT 36 TO 48 HOURS. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE...AND SHOWS EARL REACHING MAJOR HURRICANE STATUS IN THE NEXT 12 TO 24 HOURS...FOLLOWED BY A BROAD PEAK IN INTENSITY BETWEEN 36 AND 72 HOURS. AFTER THAT TIME...EARL SHOULD BEGIN TO WEAKEN AS IT MOVES OVER COOLER WATERS AND ENCOUNTERS HIGHER VERTICAL WIND SHEAR. THE OFFICIAL FORECAST IS A BLEND OF THE SHIPS MODEL AND THE GFDL. BASED ON AIRCRAFT AND SATELLITE FIXES...THE INITIAL MOTION ESTIMATE REMAINS 285/13. EARL WILL GRADUALLY TURN TOWARD THE NORTHWEST IN THE NEXT DAY OR SO AS IT MOVES AROUND THE SOUTHWESTERN EDGE OF THE SUBTROPICAL RIDGE CENTERED ALONG 25N. THE TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO AND THE OFFICIAL FORECAST IS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE ENVELOPE THROUGH 24 HOURS. AFTER THAT TIME MOST OF THE TRACK GUIDANCE HAS SHIFTED FARTHER WEST...ESPECIALLY AT 72 HOURS AND BEYOND...AS EARL TURNS NORTH-NORTHWESTWARD AND INTERACTS WITH A MID-LATITUDE TROUGH MOVING FROM THE GREAT LAKES INTO THE NORTHEASTERN U.S. GIVEN THE LARGE SHIFT IN THE MODELS...THE OFFICIAL FORECAST HAS BEEN ADJUSTED TO THE LEFT...OR WEST...BUT STILL LIES ON THE EASTERN EDGE OF THE GUIDANCE SUITE. THIS IS A GOOD TIME TO REMIND EVERYONE THAT NHC AVERAGE TRACK FORECAST ERRORS ARE 200 TO 300 MILES AT DAYS 4 AND 5. GIVEN THIS UNCERTAINTY...IT IS TOO SOON TO DETERMINE WHAT...IF ANY...PARTS OF THE U.S. EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL LATER THIS WEEK. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0900Z 18.3N 62.4W 90 KT 12HR VT 30/1800Z 19.1N 64.0W 95 KT 24HR VT 31/0600Z 20.3N 66.0W 105 KT 36HR VT 31/1800Z 21.9N 67.8W 115 KT 48HR VT 01/0600Z 24.0N 69.6W 115 KT 72HR VT 02/0600Z 29.5N 73.0W 115 KT 96HR VT 03/0600Z 35.5N 72.5W 100 KT 120HR VT 04/0600Z 42.0N 65.5W 85 KT $$ FORECASTER BRENNAN WTNT42 KNHC 301450 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST MON AUG 30 2010 THE EYE OF EARL HAS BECOME BETTER DEFINED IN VISIBLE SATELLITE IMAGERY THIS MORNING AND IS WELL-DEFINED IN RADAR IMAGERY FROM BOTH SAN JUAN AND ST. MAARTEN. AN AIR FORCE HURRICANE HUNTER AIRCRAFT MEASURED 700 MB FLIGHT-LEVEL WINDS OF 111 KT IN THE NORTHEAST EYEWALL AROUND 1200 UTC. THE AIRCRAFT HAS NOT SAMPLED THE NORTHEASTERN QUADRANT AGAIN...BUT FOUND 90 KT SFMR WINDS IN THE NORTHWEST EYEWALL AND A MINIMUM PRESSURE OF 960 MB. THIS SUPPORTS INCREASING THE INITIAL INTENSITY TO 105 KT...CATEGORY THREE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. THE LOW SHEAR AND WARM WATER ENVIRONMENT AHEAD OF EARL APPEARS CONDUCIVE FOR ADDITIONAL STRENGTHENING DURING THE NEXT FEW DAYS. THIS SUPPORTS KEEPING EARL AT MAJOR HURRICANE STRENGTH DURING THAT TIME...ALTHOUGH EYEWALL CYCLES COULD INDUCE SOME FLUCTUATIONS IN INTENSITY. THE OFFICIAL FORECAST IS AT THE UPPER END OF THE INTENSITY GUIDANCE. LATE IN THE FORECAST PERIOD INCREASING SHEAR AND COOLER SSTS SHOULD INDUCE WEAKENING. THE INITIAL MOTION REMAINS 285/13. EARL IS EXPECTED TO TURN TOWARD THE NORTHWEST WITHIN THE NEXT DAY OR SO AS IT MOVES AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT COUPLE OF DAYS. AFTER THAT TIME...EARL IS FORECAST TO TURN NORTHWARD...THEN NORTHEASTWARD AHEAD OF A MID-LATITUDE TROUGH THAT MOVES ACROSS THE GREAT LAKES AND INTO THE NORTHEAST UNITED STATES IN 4-5 DAYS. THE TRACK GUIDANCE HAS SHIFTED WESTWARD AGAIN AND THE OFFICIAL FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION. THE UPDATED TRACK FORECAST IS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE. THIS IS A GOOD TIME TO REMIND EVERYONE THAT NHC AVERAGE TRACK FORECAST ERRORS ARE 200 TO 300 MILES AT DAYS 4 AND 5. GIVEN THIS UNCERTAINTY...IT IS TOO SOON TO DETERMINE WHAT PORTION OF THE U.S. EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 30/1500Z 18.7N 63.6W 105 KT 12HR VT 31/0000Z 19.5N 65.1W 115 KT 24HR VT 31/1200Z 21.0N 67.0W 125 KT 36HR VT 01/0000Z 22.8N 68.7W 125 KT 48HR VT 01/1200Z 25.2N 70.6W 120 KT 72HR VT 02/1200Z 31.0N 73.5W 110 KT 96HR VT 03/1200Z 37.5N 71.5W 100 KT 120HR VT 04/1200Z 45.5N 63.0W 75 KT...INLAND $$ FORECASTER BROWN/BERG WTNT42 KNHC 291457 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 17 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST SUN AUG 29 2010 EARL HAS BECOME MUCH BETTER ORGANIZED IN SATELLITE IMAGERY WITH SEVERAL BANDS OF THUNDERSTORMS WRAPPING AROUND THE CENTER AND A DEVELOPING CDO. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT FOUND 850 MB FLIGHT-LEVEL WINDS OF 81 KT AND SFMR SURFACE WINDS OF 64 KT EARLIER THIS MORNING. THESE MEASUREMENTS SUPPORTED THE EARLIER UPGRADE TO HURRICANE STATUS. NORTHEASTERLY SHEAR SHOULD CONTINUE TO DECREASE TODAY...AND THE UPPER-LEVEL ENVIRONMENT APPEARS QUITE FAVORABLE FOR INTENSIFICATION DURING THE NEXT FEW DAYS. THE SHIPS...LGEM...AND GFDL MODELS SUPPORT STEADY STRENGTHENING...AND THE OFFICIAL FORECAST IS NEAR THE HIGH END OF THE GUIDANCE THROUGH 36 HOURS...PREDICTING THAT EARL WILL ATTAIN MAJOR HURRICANE DURING THAT TIME. THEREAFTER... THE NHC FORECAST IS CLOSE TO A BLEND OF THE MORE AGGRESSIVE GFDL AND THE LOWER SHIPS/LGEM MODELS. THE HURRICANE IS STILL MOVING WESTWARD OR 280/15 KT. EARL IS EXPECTED TO TURN WEST-NORTHWESTWARD AND SLOW DOWN AS IT APPROACHES THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT DAY OR SO. THE HURRICANE IS FORECAST TO TURN NORTHWESTWARD IN 2-3 DAYS AS IT ROUNDS THE RIDGE. LATE IN THE FORECAST PERIOD...A TROUGH IS FORECAST TO MOVE ACROSS THE GREAT LAKES....WHICH SHOULD RESULT IN A NORTHWARD MOTION. THE TRACK GUIDANCE IS IN GOOD AGREEMENT...BUT THE GLOBAL MODELS ARE MUCH FASTER THAN THE REGIONAL HURRICANE MODELS AT DAYS 4 AND 5. THE NHC TRACK IS ALONG THE SOUTHERN SIDE OF THE GUIDANCE ENVELOPE FOR THE FIRST 36 HOURS AND LEANS TOWARD THE FASTER SOLUTION OF THE GLOBAL MODELS AT DAYS 4 AND 5. PERSONS IN THE LEEWARD ISLANDS SHOULD REMEMBER THAT THE HURRICANE IS NOT A POINT SINCE HAZARDS EXTEND WELL AWAY FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INITIAL 29/1500Z 17.2N 58.4W 65 KT 12HR VT 30/0000Z 17.6N 60.4W 75 KT 24HR VT 30/1200Z 18.5N 62.7W 90 KT 36HR VT 31/0000Z 19.6N 64.5W 100 KT 48HR VT 31/1200Z 21.1N 66.3W 105 KT 72HR VT 01/1200Z 25.2N 69.8W 110 KT 96HR VT 02/1200Z 31.0N 72.0W 110 KT 120HR VT 03/1200Z 37.0N 71.5W 100 KT $$ FORECASTER BROWN/BERG WTNT42 KNHC 292052 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST SUN AUG 29 2010 THE SATELLITE APPEARANCE OF EARL HAS CONTINUED TO IMPROVE THROUGHOUT THE DAY. SEVERAL CURVED BANDS OF THUNDERSTORMS ARE SEEN SURROUNDING A CENTRAL DENSE OVERCAST FEATURE. THERE ARE NO HINTS OF AN EYE IN VISIBLE IMAGERY...HOWEVER AN EYE IS APPARENT IN RECENT RADAR IMAGERY FROM GUADELOUPE AND WAS ALSO REPORTED BY THE AIRCRAFT A FEW HOURS AGO. ALTHOUGH THE PLANE DID NOT FIND HIGHER FLIGHT-LEVEL OR SFMR WINDS THAN IT DID THIS MORNING...THE MINIMUM PRESSURE REPORTED WAS LOWER ON EACH SUCCESSIVE FIX AND WAS DOWN TO 978 MB. BASED ON SUBJECTIVE AND OBJECTIVE SATELLITE INTENSITY ESTIMATES... AND THE INCREASED ORGANIZATION ON SATELLITE IMAGES...THE ADVISORY INTENSITY HAS BEEN INCREASED TO 75 KT. A NOAA P-3 AIRCRAFT ON A RESEARCH MISSION SHOULD BE IN EARL SHORTLY...FOLLOWED BY THE NEXT AIR FORCE C-130 MISSION BETWEEN 0000 AND 0600 UTC. THE CENTER FIXES FROM THE AIRCRAFT FLIGHT TODAY YIELD AN INITIAL MOTION OF ABOUT 285/12...A LITTLE SLOWER THAN BEFORE. THE FORECAST REASONING REMAINS UNCHANGED FROM THE PREVIOUS ADVISORY. EARL IS EXPECTED TO BE STEERED AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT COUPLE OF DAYS. THE HURRICANE SHOULD TURN NORTHWESTWARD IN 36-48 HOURS. EARL IS FORECAST TO TURN NORTHWARD...THEN NORTHEASTWARD AHEAD OF A TROUGH THAT MOVES INTO GREAT LAKES REGION IN 4-5 DAYS. THE TRACK GUIDANCE GENERALLY AGREES WITH THIS SCENARIO...BUT THERE ARE SOME LARGE DIFFERENCES IN THE FORWARD SPEED OF EARL AT DAYS 4 AND 5. THE GLOBAL MODELS REMAIN FASTER THAN THE GFDL/HWRF AND THE OFFICIAL CONTINUES TO BE FASTER THAN THE DYNAMICAL MODEL CONSENSUS AFTER 72 HOURS. THE GLOBAL MODELS SHOW A RATHER FAVORABLE UPPER-LEVEL ENVIRONMENT FOR STRENGTHENING DURING THE NEXT COUPLE OF DAYS AS AN UPPER-LEVEL ANTICYCLONE BUILDS OVER THE SYSTEM. THE SHIPS...LGEM...AND GFDL MODELS SHOW EARL REACHING MAJOR HURRICANE STRENGTH IN A DAY OR SO AND THE OFFICIAL FORECAST FOLLOWS SUIT. LATE IN THE FORECAST PERIOD...THE HURRICANE IS EXPECTED TO BEGIN TO WEAKEN AS IT MOVES OVER COOLER SSTS AND INTO AN AREA OF INCREASING SOUTHWESTERLY SHEAR. FORECAST POSITIONS AND MAX WINDS INITIAL 29/2100Z 17.6N 59.5W 75 KT 12HR VT 30/0600Z 18.0N 61.3W 90 KT 24HR VT 30/1800Z 18.9N 63.3W 100 KT 36HR VT 31/0600Z 20.3N 65.1W 110 KT 48HR VT 31/1800Z 22.1N 66.9W 115 KT 72HR VT 01/1800Z 27.3N 70.2W 115 KT 96HR VT 02/1800Z 33.5N 71.5W 105 KT 120HR VT 03/1800Z 40.0N 68.0W 90 KT $$ FORECASTER BROWN/BERG WTNT42 KNHC 300236 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 19 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST SUN AUG 29 2010 EARL HAS STRENGTHENED OVER THE PAST FEW HOURS. THE AIR FORCE HURRICANE HUNTERS RECENTLY FOUND AN SFMR-MEASURED SURFACE WIND SPEED OF 83 KT JUST SOUTHEAST OF THE CENTER. MAXIMUM FLIGHT-LEVEL WINDS FROM THE AIRCRAFT WERE 93 KT...WHICH ADJUSTS TO 84 KT AT THE SURFACE USING THE STANDARD REDUCTION FACTOR. BASED ON THESE OBSERVATIONS...THE CURRENT INTENSITY IS SET TO 85 KT. IMAGES FROM THE GUADELOUPE AND ST. MARTIN RADARS SHOW A BANDING-TYPE EYE ABOUT 30 N MI IN DIAMETER WHILE THE RECONNAISSANCE OBSERVATIONS INDICATED THAT THE EYE WAS OPEN OVER THE NORTHWEST QUADRANT. WATER VAPOR IMAGERY SHOWS THAT THE UPPER-LEVEL OUTFLOW IS BEING IMPEDED OVER THE NORTHEAST QUADRANT...BUT IS WELL ESTABLISHED OVER THE REMAINDER OF THE CIRCULATION. A BROAD UPPER-LEVEL TROUGH IS CURRENTLY SITUATED TO THE NORTHWEST OF EARL. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT THIS TROUGH WILL SHIFT WESTWARD AND WEAKEN. THIS SHOULD CREATE A ENVIRONMENT CONDUCIVE FOR INTENSIFICATION AND THE OFFICIAL FORECAST...LIKE THE PREVIOUS ONE...SHOWS EARL BECOMING A MAJOR HURRICANE OVER THE NEXT DAY OR SO. THE NHC WIND SPEED FORECAST IS ABOVE THE INTENSITY MODEL CONSENSUS BUT BELOW THE LATEST GFDL HURRICANE MODEL GUIDANCE. INITIAL MOTION...285/13...IS ABOUT THE SAME AS IN THE PREVIOUS ADVISORY. A GRADUAL TURN TO THE NORTHWEST IS LIKELY TO TAKE PLACE IN 24 TO 36 HOURS AS THE HURRICANE ENCOUNTERS THE WESTERN PERIPHERY OF A MID-TROPOSPHERIC ANTICYCLONE. BY DAYS 3 TO 4...THE HEADING AND FORWARD SPEED OF EARL ARE DEPENDENT ON THE DETAILS OF THE EVOLUTION OF A 500 MB TROUGH MOVING THROUGH THE GREAT LAKES. THE GFS AND ECMWF SHOW THIS TROUGH AMPLIFYING MORE THAN THE OTHER DYNAMICAL MODELS AND MOVE EARL SIGNIFICANTLY FASTER TO THE NORTH-NORTHEAST WITH A SHARPER EASTWARD TURN THAN THE OTHER GUIDANCE. THE OFFICIAL TRACK FORECAST IS NOT QUITE AS FAST AS THE GFS AND ECMWF...BUT IS CLOSE TO THE MULTI-MODEL CONSENSUS. THE FORECAST WIND RADII HAVE BEEN EXPANDED A LITTLE BASED ON DYNAMICAL...MAINLY GLOBAL MODEL...GUIDANCE. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0300Z 17.9N 61.1W 85 KT 12HR VT 30/1200Z 18.5N 62.7W 90 KT 24HR VT 31/0000Z 19.6N 64.6W 100 KT 36HR VT 31/1200Z 21.1N 66.4W 110 KT 48HR VT 01/0000Z 22.8N 68.2W 115 KT 72HR VT 02/0000Z 27.5N 71.5W 115 KT 96HR VT 03/0000Z 34.0N 72.0W 100 KT 120HR VT 04/0000Z 40.0N 67.0W 85 KT $$ FORECASTER PASCH 000 WTNT42 KNHC 300845 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST MON AUG 30 2010 SINCE THE AIRCRAFT DEPARTED JUST PRIOR TO 0600 UTC...AN EYE HAS BEEN OCCASIONALLY APPARENT IN INFRARED IMAGERY...AND HAS BECOME BETTER DEFINED WITH A DIAMETER OF ABOUT 25 NM ON THE ST. MAARTEN RADAR. THE AIRCRAFT MEASURED A FLIGHT LEVEL MAXIMUM WIND OF 97 KT AT 0510 UTC...AND 0600 UTC DVORAK INTENSITY ESTIMATES WERE 90 KT FROM TAFB AND SAB. BASED ON THESE DATA...THE INITIAL INTENSITY IS SET TO 90 KT FOR THIS ADVISORY. THE OUTFLOW IS IMPROVING IN THE NORTHEASTERN QUADRANT AND IS GOOD ELSEWHERE...AND THE OVERALL ENVIRONMENT SHOULD SUPPORT STEADY INTENSIFICATION THROUGH THE NEXT 36 TO 48 HOURS. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS ONE...AND SHOWS EARL REACHING MAJOR HURRICANE STATUS IN THE NEXT 12 TO 24 HOURS...FOLLOWED BY A BROAD PEAK IN INTENSITY BETWEEN 36 AND 72 HOURS. AFTER THAT TIME...EARL SHOULD BEGIN TO WEAKEN AS IT MOVES OVER COOLER WATERS AND ENCOUNTERS HIGHER VERTICAL WIND SHEAR. THE OFFICIAL FORECAST IS A BLEND OF THE SHIPS MODEL AND THE GFDL. BASED ON AIRCRAFT AND SATELLITE FIXES...THE INITIAL MOTION ESTIMATE REMAINS 285/13. EARL WILL GRADUALLY TURN TOWARD THE NORTHWEST IN THE NEXT DAY OR SO AS IT MOVES AROUND THE SOUTHWESTERN EDGE OF THE SUBTROPICAL RIDGE CENTERED ALONG 25N. THE TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO AND THE OFFICIAL FORECAST IS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE ENVELOPE THROUGH 24 HOURS. AFTER THAT TIME MOST OF THE TRACK GUIDANCE HAS SHIFTED FARTHER WEST...ESPECIALLY AT 72 HOURS AND BEYOND...AS EARL TURNS NORTH-NORTHWESTWARD AND INTERACTS WITH A MID-LATITUDE TROUGH MOVING FROM THE GREAT LAKES INTO THE NORTHEASTERN U.S. GIVEN THE LARGE SHIFT IN THE MODELS...THE OFFICIAL FORECAST HAS BEEN ADJUSTED TO THE LEFT...OR WEST...BUT STILL LIES ON THE EASTERN EDGE OF THE GUIDANCE SUITE. THIS IS A GOOD TIME TO REMIND EVERYONE THAT NHC AVERAGE TRACK FORECAST ERRORS ARE 200 TO 300 MILES AT DAYS 4 AND 5. GIVEN THIS UNCERTAINTY...IT IS TOO SOON TO DETERMINE WHAT...IF ANY...PARTS OF THE U.S. EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL LATER THIS WEEK. FORECAST POSITIONS AND MAX WINDS INITIAL 30/0900Z 18.3N 62.4W 90 KT 12HR VT 30/1800Z 19.1N 64.0W 95 KT 24HR VT 31/0600Z 20.3N 66.0W 105 KT 36HR VT 31/1800Z 21.9N 67.8W 115 KT 48HR VT 01/0600Z 24.0N 69.6W 115 KT 72HR VT 02/0600Z 29.5N 73.0W 115 KT 96HR VT 03/0600Z 35.5N 72.5W 100 KT 120HR VT 04/0600Z 42.0N 65.5W 85 KT $$ FORECASTER BRENNAN WTNT42 KNHC 301450 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST MON AUG 30 2010 THE EYE OF EARL HAS BECOME BETTER DEFINED IN VISIBLE SATELLITE IMAGERY THIS MORNING AND IS WELL-DEFINED IN RADAR IMAGERY FROM BOTH SAN JUAN AND ST. MAARTEN. AN AIR FORCE HURRICANE HUNTER AIRCRAFT MEASURED 700 MB FLIGHT-LEVEL WINDS OF 111 KT IN THE NORTHEAST EYEWALL AROUND 1200 UTC. THE AIRCRAFT HAS NOT SAMPLED THE NORTHEASTERN QUADRANT AGAIN...BUT FOUND 90 KT SFMR WINDS IN THE NORTHWEST EYEWALL AND A MINIMUM PRESSURE OF 960 MB. THIS SUPPORTS INCREASING THE INITIAL INTENSITY TO 105 KT...CATEGORY THREE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. THE LOW SHEAR AND WARM WATER ENVIRONMENT AHEAD OF EARL APPEARS CONDUCIVE FOR ADDITIONAL STRENGTHENING DURING THE NEXT FEW DAYS. THIS SUPPORTS KEEPING EARL AT MAJOR HURRICANE STRENGTH DURING THAT TIME...ALTHOUGH EYEWALL CYCLES COULD INDUCE SOME FLUCTUATIONS IN INTENSITY. THE OFFICIAL FORECAST IS AT THE UPPER END OF THE INTENSITY GUIDANCE. LATE IN THE FORECAST PERIOD INCREASING SHEAR AND COOLER SSTS SHOULD INDUCE WEAKENING. THE INITIAL MOTION REMAINS 285/13. EARL IS EXPECTED TO TURN TOWARD THE NORTHWEST WITHIN THE NEXT DAY OR SO AS IT MOVES AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE DURING THE NEXT COUPLE OF DAYS. AFTER THAT TIME...EARL IS FORECAST TO TURN NORTHWARD...THEN NORTHEASTWARD AHEAD OF A MID-LATITUDE TROUGH THAT MOVES ACROSS THE GREAT LAKES AND INTO THE NORTHEAST UNITED STATES IN 4-5 DAYS. THE TRACK GUIDANCE HAS SHIFTED WESTWARD AGAIN AND THE OFFICIAL FORECAST HAS BEEN ADJUSTED IN THAT DIRECTION. THE UPDATED TRACK FORECAST IS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED GUIDANCE. THIS IS A GOOD TIME TO REMIND EVERYONE THAT NHC AVERAGE TRACK FORECAST ERRORS ARE 200 TO 300 MILES AT DAYS 4 AND 5. GIVEN THIS UNCERTAINTY...IT IS TOO SOON TO DETERMINE WHAT PORTION OF THE U.S. EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 30/1500Z 18.7N 63.6W 105 KT 12HR VT 31/0000Z 19.5N 65.1W 115 KT 24HR VT 31/1200Z 21.0N 67.0W 125 KT 36HR VT 01/0000Z 22.8N 68.7W 125 KT 48HR VT 01/1200Z 25.2N 70.6W 120 KT 72HR VT 02/1200Z 31.0N 73.5W 110 KT 96HR VT 03/1200Z 37.5N 71.5W 100 KT 120HR VT 04/1200Z 45.5N 63.0W 75 KT...INLAND $$ FORECASTER BROWN/BERG WTNT42 KNHC 302047 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 22 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST MON AUG 30 2010 THE RECONNAISSANCE AIRCRAFT MEASURED 116 KT FLIGHT-LEVEL WINDS AND 108 KT SFMR SURFACE WINDS SHORTLY AFTER 1500 UTC. THIS WAS THE BASIS FOR THE EARLIER INCREASE IN INTENSITY. SINCE THAT TIME...THE PRESSURE HAS CONTINUED TO DROP AND WAS DOWN TO 955 MB ON THE LAST DROPSONDE RELEASED IN THE EYE AROUND 1700 UTC. SINCE THE AIRCRAFT DEPARTED EARL...THE EYE HAS CONTINUED TO CLEAR AND IS SURROUNDED BY CLOUD TOPS TO -70 DEGREES CELSIUS OR COLDER. OBJECTIVE SATELLITE INTENSITY ESTIMATES HAVE INCREASED TO JUST ABOVE 6.0 ON THE DVORAK SCALE AND SUPPORT AN INITIAL INTENSITY OF 115 KT...CATEGORY FOUR ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE. EARL IS EXPECTED TO REMAIN IN A LOW SHEAR ENVIRONMENT AND OVER WARM WATER DURING THE NEXT FEW DAYS AND SOME ADDITIONAL STRENGTHENING IS LIKELY IN THE SHORT TERM. THEREAFTER...EYEWALL CYCLES WILL LIKELY INDUCE SOME FLUCTUATIONS IN INTENSITY...WHICH ARE DIFFICULT TO PREDICT. THE NHC FORECAST IS AGAIN NEAR THE HIGH END OF THE INTENSITY GUIDANCE. AT DAYS 4 AND 5...THE HURRICANE IS FORECAST TO MOVE OVER COOLER WATER AND INTO AN AREA OF INCREASING SHEAR WHICH SHOULD RESULT IN WEAKENING. THE INITIAL MOTION IS 290/13. THE FORECAST REASONING REMAINS UNCHANGED AS EARL IS EXPECTED TO TURN NORTHWESTWARD IN ABOUT 24 HOURS AROUND THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. THE TRACK GUIDANCE HAS SHIFTED NOTICEABLY WESTWARD DURING THE FIRST 48 HOURS...WITH THE GFS AND ECMWF ON THE EASTERN EDGE OF THE ENVELOPE. THE OFFICIAL FORECAST HAS BEEN ADJUSTED WESTWARD... PRIMARILY THROUGH 72 HOURS...AND LIES BETWEEN THE GFS/ECMWF AND THE MULTI-MODEL CONSENSUS. THIS IS A GOOD TIME TO REMIND EVERYONE THAT NHC AVERAGE TRACK FORECAST ERRORS ARE 200 TO 300 MILES AT DAYS 4 AND 5. GIVEN THIS UNCERTAINTY...IT IS TOO SOON TO DETERMINE WHAT PORTION OF THE U.S. EAST COAST MIGHT SEE DIRECT IMPACTS FROM EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 30/2100Z 19.3N 64.7W 115 KT 12HR VT 31/0600Z 20.2N 66.3W 125 KT 24HR VT 31/1800Z 21.7N 68.1W 130 KT 36HR VT 01/0600Z 23.4N 70.1W 130 KT 48HR VT 01/1800Z 25.8N 72.1W 125 KT 72HR VT 02/1800Z 31.6N 74.7W 115 KT 96HR VT 03/1800Z 38.0N 71.0W 95 KT 120HR VT 04/1800Z 45.5N 63.0W 70 KT...INLAND $$ FORECASTER BROWN WTNT42 KNHC 310250 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 23 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST MON AUG 30 2010 THE INTENSITY OF EARL APPEARS TO HAVE LEVELED OFF FOR THE TIME BEING. DROPSONDE MEASUREMENTS FROM THE AIR FORCE RESERVE HURRICANE HUNTERS INDICATE LITTLE CHANGE IN CENTRAL PRESSURE OVER THE PAST FEW HOURS. THERE WAS ALSO AN UNFLAGGED SFMR-MEASURED SURFACE WIND OF 111 KT. THE CURRENT INTENSITY IS HELD AT 115 KT FOR THIS ADVISORY. WSR-88D RADAR DATA FROM SAN JUAN SUGGEST THAT A CONCENTRIC EYEWALL OR CONVECTIVE RING MAY BE FORMING. THIS WOULD AT LEAST TEMPORARILY HALT FURTHER INTENSIFICATION. WATER VAPOR IMAGERY CONTINUES TO DEPICT A BROAD UPPER-LEVEL TROUGH TO THE NORTHWEST OF THE HURRICANE. GLOBAL MODELS FORECAST AN UPPER-LEVEL LOW TO CUT OFF FROM THE TROUGH AND MOVE SOUTHWARD...WHICH IS AN UPPER-LEVEL FLOW EVOLUTION THAT IS USUALLY CONDUCIVE FOR STRENGTHENING. HOWEVER THE GFS PREDICTS AROUND 18-20 KT OF SOUTH-SOUTHWESTERLY VERTICAL SHEAR OVER EARL IN 24-48 HOURS. THE OFFICIAL INTENSITY FORECAST HAS BACKED OFF SOME FROM THE PREVIOUS ONE...AND SHOWS ONLY SLIGHT STRENGTHENING OVER THE NEXT DAY OR SO. ALSO...SOME OSCILLATIONS IN INTENSIYY DUE TO EYEWALL REPLACEMENTS OR OTHER INNER-CORE CONVECTIVE PROCESSES ARE ALSO POSSIBLE. THERE HAVE BEEN SOME WOBBLES IN THE TRACK OF EARL BUT THE MEAN MOTION HAS BEEN ABOUT 300/12 OVER THE PAST 6 HOURS. A GRADUAL TURN TOWARD THE NORTHWEST IS LIKELY IN 12 TO 24 HOURS AS EARL MOVES AROUND THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. BY DAY 3...A GENERALLY NORTHWARD TRACK IS EXPECTED AS THE HURRICANE MOVES ALONG THE WESTERN SIDE OF THE RIDGE. A STRONG MID-TROPOSPHERIC TROUGH MOVING THROUGH THE GREAT LAKES SHOULD PROVIDE AN EASTWARD COMPONENT OF STEERING BY DAY 4...AND EARL IS LIKELY TO ACCELERATE NORTH-NORTHEASTWARD AHEAD OF THE TROUGH NEAR THE END OF THE FORECAST PERIOD. THE TRACK GUIDANCE SUITE IS IN RATHER CLOSE AGREEMENT UP TO 72 HOURS...BUT BECOMES MORE DIVERGENT AFTER THAT FORECAST TIME. THE OFFICIAL TRACK FORECAST IS...ONCE AGAIN... SHIFTED SLIGHTLY WESTWARD FROM THE PREVIOUS ONE AND IS VERY CLOSE TO THE MULTI-MODEL CONSENSUS. INTERESTS FROM THE CAROLINAS NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL. THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO HOW CLOSE THE HURRICANE WILL COME TO THE U.S. EAST COAST. FORECAST POSITIONS AND MAX WINDS INITIAL 31/0300Z 19.9N 65.8W 115 KT 12HR VT 31/1200Z 20.9N 67.2W 120 KT 24HR VT 01/0000Z 22.6N 69.2W 120 KT 36HR VT 01/1200Z 24.6N 71.4W 120 KT 48HR VT 02/0000Z 26.9N 73.4W 120 KT 72HR VT 03/0000Z 32.5N 75.0W 110 KT 96HR VT 04/0000Z 38.5N 70.5W 90 KT 120HR VT 05/0000Z 46.0N 62.0W 60 KT $$ FORECASTER PASCH WTNT42 KNHC 310902 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 24 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM AST TUE AUG 31 2010 AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT EARLIER REPORTED 700 MB FLIGHT-LEVEL WINDS OF 124 KT...AND ESTIMATED SURFACE WINDS OF 112 KT FROM THE SFMR. THE PLANE ALSO REPORTED A CENTRAL PRESSURE OF 931 MB. BASED ON THIS...THE INITIAL INTENSITY IS SET AT 115 KT. SINCE THE PLANE LEFT...A TRMM OVERPASS AND DATA FROM THE SAN JUAN WSR-88D RADAR INDICATE THAT EARL HAS STARTED AN EYEWALL REPLACEMENT CYCLE. ANOTHER HURRICANE HUNTER AIRCRAFT WILL ARRIVE IN EARL NEAR 12Z TO DETERMINE IF IT HAS PEAKED IN INTENSITY FOR NOW. THE INITIAL MOTION IS A WOBBLY 295/11. THERE IS LITTLE CHANGE TO THE TRACK FORECAST PHILOSOPHY FROM THE PREVIOUS ADVISORY. EARL SHOULD MOVE GENERALLY NORTHWESTWARD FOR THE NEXT 48 HR OR SO ON THE SOUTHWESTERN SIDE OF THE SUBTROPICAL RIDGE. AFTER THAT...THE HURRICANE SHOULD TURN NORTHWARD AROUND THE WESTERN END OF THE RIDGE...FOLLOWED BY A TURN TO THE NORTH-NORTHEAST AND ACCELERATION ON THE EAST SIDE OF A STRONG DEEP-LAYER TROUGH MOVING INTO THE NORTHEASTERN UNITED STATES. THE TRACK GUIDANCE IS TIGHTLY CLUSTERED FOR THE FIRST 72 HR...WITH SOME SPREAD IN THE TRACK DIRECTIONS BETWEEN THE LEFT-MOST HWRF AND THE RIGHT-MOST GFS ENSEMBLE MEAN THEREAFTER. THE NEW FORECAST TRACK IS AN UPDATE OF THE PREVIOUS TRACK AND LIES JUST LEFT OF THE CENTER OF THE GUIDANCE ENVELOPE. THE INTENSITY FORECAST IS A LITTLE PROBLEMATIC. THE GFDL AND GFDN MODELS SUGGEST THAT EARL COULD STRENGTHEN DURING THE NEXT 24 HR OR SO...AND THIS COULD OCCUR IF THE HURRICANE COMPLETES THE EYEWALL REPLACEMENT QUICKLY ENOUGH. ON THE OTHER HAND...EARL IS FORECAST TO BE IN AN ENVIRONMENT OF MODERATE SOUTHWESTERLY VERTICAL WIND SHEAR...AND WATER VAPOR IMAGERY SHOWS VERY DRY MID/UPPER-LEVEL AIR APPROACHING THE HURRICANE FROM THE NORTH. THESE FACTORS COULD PREVENT ADDITIONAL STRENGTHENING. THE INTENSITY FORECAST WILL FOLLOW THE GFDL/GFDN SCENARIO WITH A LITTLE MORE STRENGTHENING DURING THE NEXT 12-24 HR...BASED ON THE HURRICANE COMPLETING THE EYEWALL REPLACEMENT AND THE DRY AIR NOT REACHING THE HURRICANE CORE. THE FORECAST TRACK TAKES EARL OVER COLDER SEA SURFACE TEMPERATURES AND INTO INCREASING SHEAR AFTER 72 HR...WHICH SHOULD CAUSE STEADY WEAKENING AND EVENTUAL EXTRATROPICAL TRANSITION. INTERESTS FROM THE CAROLINAS NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL. THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO HOW CLOSE THE HURRICANE WILL COME TO THE U.S. EAST COAST. FORECAST POSITIONS AND MAX WINDS INITIAL 31/0900Z 20.5N 66.7W 115 KT 12HR VT 31/1800Z 21.4N 68.2W 120 KT 24HR VT 01/0600Z 23.3N 70.3W 120 KT 36HR VT 01/1800Z 25.5N 72.3W 120 KT 48HR VT 02/0600Z 28.0N 73.8W 115 KT 72HR VT 03/0600Z 33.5N 74.5W 105 KT 96HR VT 04/0600Z 40.0N 69.5W 85 KT 120HR VT 05/0600Z 48.0N 60.5W 60 KT...POST-TROP/EXTRATROP $$ FORECASTER BEVEN WTNT42 KNHC 311457 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 25 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM AST TUE AUG 31 2010 THE EYE HAS BECOME OBSCURED ON VISIBLE IMAGES AND THIS IS REFLECTED IN A DECREASE IN THE DVORAK NUMBERS AND IN AN INCREASE IN THE PRESSURE TO 939 MB. THIS APPARENT WEAKENING IS MOST LIKELY RELATED TO AN ONGOING EYEWALL REPLACEMENT CYCLE AS INDICATED BY THE DOUBLE EYE STRUCTURE OBSERVED ON MICROWAVE DATA AT 1035 UTC. HOWEVER...AN AVERAGE OF THE FLIGHT-LEVEL WINDS AND SFMR DATA FROM THE AIR FORCE RECONNAISSANCE PLANE STILL SUPPORTS AN INITIAL INTENSITY OF 115 KNOTS. NO CHANGE IN INTENSITY IS EXPECTED TODAY BUT THERE IS A CHANCE FOR EARL TO STRENGTHEN A LITTLE DURING THE NEXT 24 HOURS IF THE OUTER EYEWALL SHRINKS. DESPITE THE FLUCTUATIONS IN INTENSITY... EARL MOST LIKELY WILL RETAIN CATEGORY FOUR STATUS FOR THE NEXT 48 HOURS. A GRADUAL WEAKENING SHOULD BEGIN THEREAFTER AS THE SHEAR INCREASES. EARL HAS CONTINUED TO WOBBLE DURING THE PAST FEW HOURS BUT THE AVERAGE MOTION IS TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 12 KNOTS. EARL HAS BEEN STEERED BY THE FLOW AROUND A SUBTROPICAL RIDGE EXTENDING FROM THE EASTERN UNITED STATES EASTWARD ACROSS THE ATLANTIC. THIS PATTERN WILL KEEP EARL ON A GENERAL WEST-NORTHWEST TO NORTHWEST TRACK DURING THE NEXT 24 TO 48 HOURS. THEREAFTER...THE SUBTROPICAL RIDGE WILL MOVE EAST AND EARL WILL LIKELY TURN NORTH AND NORTHEAST BETWEEN THE RIDGE AND MID-LEVEL TROUGH OVER THE EASTERN UNITED STATES. THIS IS THE SCENARIO PROVIDED BY MOST OF THE DYNAMICAL MODELS. THE OFFICIAL FORECAST HAS SHIFTED A LITTLE TO THE WEST BEFORE 48 HOURS AND IS ON THE WESTERN EDGE OF THE GUIDANCE ENVELOPE. GIVEN THE TRACK AND THE LARGE AREA OF TROPICAL STORM FORCE WINDS...A HURRICANE WATCH WILL LIKELY BE REQUIRED FOR A PORTION OF THE MID-ATLANTIC COAST LATER TODAY. INTERESTS FROM THE CAROLINAS NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL. THERE IS STILL CONSIDERABLE UNCERTAINTY AS TO HOW CLOSE THE HURRICANE WILL COME TO THE U.S. EAST COAST. FORECAST POSITIONS AND MAX WINDS INITIAL 31/1500Z 21.2N 67.9W 115 KT 12HR VT 01/0000Z 22.3N 69.7W 115 KT 24HR VT 01/1200Z 24.8N 71.7W 120 KT 36HR VT 02/0000Z 27.3N 73.5W 115 KT 48HR VT 02/1200Z 30.5N 75.0W 115 KT 72HR VT 03/1200Z 36.5N 73.0W 100 KT 96HR VT 04/1200Z 43.5N 66.0W 80 KT 120HR VT 05/1200Z 52.5N 57.0W 55 KT...POST-TROP/EXTRATROP $$ FORECASTER AVILA WTNT42 KNHC 312043 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 26 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM AST TUE AUG 31 2010 ALTHOUGH THE SATELLITE PRESENTATION IS NOT AS IMPRESSIVE AS IT WAS EARLIER...A RECONNAISSANCE PLANE AROUND 1700 UTC REPORTED A MINIMUM PRESSURE OF 940 MB AND MAXIMUM FLIGHT-LEVEL WINDS OF 128 KNOTS. THESE DATA SUPPORT AN INITIAL INTENSITY OF 115 KNOTS. CURRENTLY...THERE IS SOME SOUTHWESTERLY SHEAR DISRUPTING THE UPPER-LEVEL OUTFLOW OVER THE WESTERN SEMICIRCLE OF EARL. THIS SHEAR IS CAUSED BY A WEAK UPPER-LOW OR TROUGH OVER THE EASTERN BAHAMAS AS OBSERVED ON WATER VAPOR IMAGES. HOWEVER...MODELS WEAKEN THE UPPER LOW AS EARL MOVES AROUND IT...RESULTING IN A MORE FAVORABLE ENVIRONMENT. EARL IS EXPECTED TO MAINTAIN ITS CATEGORY FOUR INTENSITY FOR THE NEXT DAY OR TWO. EARL HAS BEGUN TO MOVE TOWARD THE NORTHWEST OR 305 DEGREES AT 12 OR 13 KNOTS DURING THE PAST FEW HOURS. THE SUBTROPICAL HIGH THAT IS STEERING EARL TOWARD THE WEST-NORTHWEST OR NORTHWEST IS FORECAST TO GRADUALLY SHIFT EASTWARD AS A BROAD TROUGH BECOMES ESTABLISHED OVER THE EASTERN UNITED STATES. THIS PATTERN WILL FORCE EARL ON A MORE NORTHWESTERLY AND NORTHERLY TRACK FOR THE NEXT DAY OR TWO. THEREAFTER...EARL WILL REACH THE BASE OF THE MID-LATITUDE WESTERLIES AND WILL LIKELY TURN SHARPLY TO THE NORTHEAST WITH AN INCREASE IN FORWARD SPEED. THIS IS THE SOLUTION UNANIMOUSLY PROVIDED BY TRACK GUIDANCE. ONCE AGAIN THE OFFICIAL FORECAST HAS BEEN SHIFTED A FEW MILES TO THE WEST BEFORE 48 HOURS FOLLOWING THE TRENDS OF THE ECMWF AND THE GFS. GIVEN THE LARGE AREA OF TROPICAL STORM FORCE WINDS ASSOCIATED WITH EARL...AND THE NEW DEFINITION OF WATCHES AND WARNINGS...A HURRICANE AND TROPICAL STORM WATCH HAS BEEN ISSUED FOR A PORTION OF THE MID- ATLANTIC COAST. INTERESTS FROM VIRGINIA NORTHWARD TO NEW ENGLAND SHOULD MONITOR THE PROGRESS OF EARL. FORECAST POSITIONS AND MAX WINDS INITIAL 31/2100Z 22.0N 68.8W 115 KT 12HR VT 01/0600Z 23.3N 70.5W 115 KT 24HR VT 01/1800Z 25.6N 72.8W 115 KT 36HR VT 02/0600Z 28.0N 74.5W 115 KT 48HR VT 02/1800Z 31.0N 75.5W 115 KT 72HR VT 03/1800Z 36.0N 73.5W 95 KT 96HR VT 04/1800Z 44.0N 65.0W 75 KT 120HR VT 05/1800Z 56.0N 55.0W 50 KT...POST-TROP/EXTRATROP $$ FORECASTER AVILA WTNT42 KNHC 010248 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 27 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM AST TUE AUG 31 2010 EARL REMAINS A WELL-ORGANIZED HURRICANE ON SATELLITE IMAGES. AN EYE OF ABOUT 20 N MI IN DIAMETER IS EVIDENT ON THE INFRARED IMAGES... AND THE UPPER-LEVEL OUTFLOW IS WELL-DEFINED OVER ALL BUT THE SOUTHWEST PART OF THE CIRCULATION...AS CONFIRMED BY SURVELLIANCE DATA FROM THE NOAA G-IV JET THIS EVENING. THE INITIAL INTENSITY IS KEPT AT 115 KT BASED ON A DVORAK ESTIMATE FROM TAFB. THERE IS CURRENTLY ABOUT 20 KT OF SOUTHWESTERLY SHEAR OVER EARL AS DEPICTED BY UW-CIMSS ANALYSES. THIS SHEAR SHOULD LESSEN AS AN UPPER-LEVEL TROUGH...JUST TO THE WEST AND NORTHWEST OF THE HURRICANE...IS PREDICTED BY THE GLOBAL MODELS TO SHIFT WESTWARD OVER THE NEXT DAY OR SO. THIS EVOLUTION OF THE UPPER-LEVEL ENVIRONMENT SHOULD ALLOW EARL TO MORE OR LESS MAINTAIN ITS INTENSITY FOR ABOUT THE NEXT 36 HOURS. THE NHC INTENSITY FORECAST IS ONLY A LITTLE ABOVE THE STATISTICAL/DYNAMICAL LGEM GUIDANCE AND A LITTLE BELOW THE GFDL HURRICANE MODEL GUIDANCE. BY DAY 4...GLOBAL MODELS SHOW EARL BECOME EMBEDDED WITHIN A BAROCLINIC ZONE WITH WELL-DEFINED THERMAL ADVECTION SO EXTRATROPICAL TRANSITION SHOULD HAVE OCCURRED BY THAT TIME. THE TRACK HAS BEEN WOBBLING AS IS TYPICAL OF INTENSE HURRICANES BUT THE MEAN MOTION OVER THE PAST 6 HOURS IS ABOUT 310/13. THERE HAS BEEN LITTLE CHANGE TO THE NHC FORECAST TRACK OR REASONING. EARL IS EXPECTED TO GRADUALLY TURN TO THE RIGHT AS IT MOVES AROUND THE WESTERN PERIPHERY OF A MID-LEVEL SUBTROPICAL ANTICYCLONE FOR THE NEXT COUPLE OF DAYS. AFTERWARDS...A VIGOROUS MID-LATITUDE TROUGH AT 500 MB WILL APPROACH THE EAST COAST AND SHOULD CAUSE THE HURRICANE TO TURN TOWARD THE NORTH-NORTHEAST. OF COURSE...THE TIMING OF THIS TURN IS CRITICAL IN DETERMINING HOW CLOSE THE CENTER WILL COME TO THE U.S. EAST COAST. ONE SHOULD NOT FOCUS ON THE EXACT FORECAST TRACK BECAUSE OF FORECAST UNCERTAINTY...AND ALSO BECAUSE EARL IS A LARGE HURRICANE AND SIGNIFICANT IMPACTS CAN BE WELL REMOVED FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INITIAL 01/0300Z 23.0N 69.9W 115 KT 12HR VT 01/1200Z 24.5N 71.6W 115 KT 24HR VT 02/0000Z 27.0N 73.5W 115 KT 36HR VT 02/1200Z 29.8N 75.0W 115 KT 48HR VT 03/0000Z 32.7N 75.2W 110 KT 72HR VT 04/0000Z 39.0N 70.5W 90 KT 96HR VT 05/0000Z 47.0N 62.0W 75 KT...POST-TROP/EXTRATROP 120HR VT 06/0000Z 56.0N 58.0W 50 KT...POST-TROP/EXTRATROP $$ FORECASTER PASCH/KIMBERLAIN WTNT42 KNHC 010903 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 28 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM EDT WED SEP 01 2010 THE EYE OF EARL HAS BECOME LESS DISTINCT IN SATELLITE IMAGERY DURING THE PAST FEW HOURS...AND THE EYEWALL CLOUD TOPS HAVE WARMED A LITTLE. AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT REPORTED A CENTRAL PRESSURE OF 941 MB...WHICH IS LITTLE CHANGED FROM EARLIER. HOWEVER...THE MAXIMUM FLIGHT-LEVEL WINDS WERE 116 KT...WHICH WAS LOWER THAN THE PREVIOUS MISSION...AND SURFACE WIND ESTIMATES FROM THE SFMR WERE UNDER 100 KT. THE INITIAL INTENSITY IS DECREASED TO 110 KT...AND THIS COULD BE A LITTLE GENEROUS. EARL IS MOVING 310-315 DEGREES AT ABOUT 14 KT. FOR THE NEXT 36 OR SO...THE HURRICANE SHOULD CONTINUE TO MOVE GENERALLY NORTHWESTWARD ON THE SOUTHWESTERN SIDE OF A LOW/MID-LEVEL RIDGE OVER THE CENTRAL ATLANTIC. AFTER THAT...EARL IS EXPECTED TO TURN NORTHWARD AND THEN NORTH-NORTHEASTWARD AS IT ROUNDS THE END OF THE RIDGE AND ENTERS THE WESTERLIES ASSOCIATED WITH A DEEP-LAYER TROUGH MOVING INTO THE NORTHEASTERN UNITED STATES. THE TRACK GUIDANCE IS IN GOOD AGREEMENT WITH THIS SCENARIO. HOWEVER...THERE ARE SOME SMALL DIFFERENCE IN THE MODEL GUIDANCE THAT COULD HAVE LARGE IMPLICATIONS IN TERMS OF IMPACTS. THE GFDN...NOGAPS...AND UKMET FORECAST THE CENTER TO PASS NEAR OR OVER THE NORTH CAROLINA COAST AND NEW ENGLAND. THE OTHER MODELS ARE FARTHER TO THE EAST...KEEPING THE CENTER OFFSHORE. THROUGH 48 HR...THE NEW FORECAST TRACK IS SIMILAR TO THE PREVIOUS TRACK...KEEPS THE CENTER OFF THE NORTH CAROLINA COAST...AND LIES JUST WEST OF THE CENTER OF THE GUIDANCE ENVELOPE. AFTER 48 HR...THE GUIDANCE ENVELOPE HAS SHIFTED A LITTLE TO THE WEST...AND THE NEW FORECAST TRACK DOES LIKEWISE TO BE IN THE CENTER OF THE ENVELOPE. THIS PART OF THE TRACK IS CLOSER TO THE NEW ENGLAND STATES THAN THE PREVIOUS FORECAST. THE INTENSITY FORECAST IS A CONUNDRUM. ON THE FAVORABLE SIDE...THE HURRICANE IS OVER VERY WARM SEA SURFACE TEMPERATURES...HAS GOOD CIRRUS OUTFLOW IN ALL DIRECTIONS EXCEPT TO THE SOUTH...AND HAS A GOOD CONVECTIVE STRUCTURE. ON THE NEGATIVE SIDE...EARL IS EXPERIENCING 15-20 KT OF SOUTHWESTERLY VERTICAL WIND SHEAR...AND WATER VAPOR IMAGERY SHOWS A TONGUE OF MID/UPPER-LEVEL DRY AIR WRAPPED MORE THAN HALFWAY AROUND THE CYCLONE. SOME SHEAR IS LIKELY TO CONTINUE FOR THE NEXT 36-48 HR...AND NONE OF THE INTENSITY GUIDANCE CALLS FOR MUCH STRENGTHENING AT THIS TIME. BASED ON THIS...THE NHC INTENSITY FORECAST CALLS FOR LITTLE CHANGE IN STRENGTH FOR 36 HR...FOLLOWED BY WEAKENING AS EARL ENCOUNTERS COOLER SEA SURFACE TEMPERATURES AND INCREASING SHEAR. EARL IS EXPECTED TO BECOME EXTRATROPICAL BY 96 HR. HURRICANE WARNINGS WILL LIKELY BE REQUIRED FOR PORTIONS OF THE NORTH CAROLINA COAST LATER THIS MORNING. FORECAST POSITIONS AND MAX WINDS INITIAL 01/0900Z 24.0N 71.2W 110 KT 12HR VT 01/1800Z 25.8N 72.9W 110 KT 24HR VT 02/0600Z 28.5N 74.6W 110 KT 36HR VT 02/1800Z 31.3N 75.2W 110 KT 48HR VT 03/0600Z 34.6N 74.4W 105 KT 72HR VT 04/0600Z 42.0N 68.0W 85 KT 96HR VT 05/0600Z 50.0N 61.5W 60 KT...POST-TROP/EXTRATROP 120HR VT 06/0600Z 57.0N 58.0W 45 KT...POST-TROP/EXTRATROP $$ FORECASTER BEVEN WTNT42 KNHC 011455 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 29 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM EDT WED SEP 01 2010 VISIBLE SATELLITE IMAGES THIS MORNING SHOW THAT EARL HAS A DISTINCT EYE SURROUNDED BY MODERATE TO STRONG CONVECTION. A BLEND BETWEEN SATELLITE INTENSITY ESTIMATES AND DATA FROM A NOAA RECONNAISSANCE PLANE SUGGEST THAT WINDS ARE STILL 110 KNOTS. GIVEN THE CURRENT SATELLITE PRESENTATION...WHICH SHOWS A DECREASE IN THE SHEAR SINCE YESTERDAY AND THE WARM OCEAN ALONG THE TRACK OF EARL...THERE IS A POSSIBILITY THAT THE HURRICANE COULD REGAIN SOME INTENSITY. HOWEVER...MOST OF THE GUIDANCE WITH THE EXCEPTION OF THE GFDL MODEL SHOWS A STEADY STATE OR GRADUAL WEAKENING DURING THE NEXT DAY OR TWO...AND THIS TREND IS FOLLOWED IN THE OFFICIAL FORECAST. AFTER 48 HOURS...EARL SHOULD BEGIN TO MOVE OVER COOLER WATERS AND ENCOUNTER INCREASING SHEAR RESULTING IN WEAKENING. BY DAY 5 THE HURRICANE SHOULD HAVE BEEN ABSORBED BY A LARGE EXTRATROPICAL CYCLONE WELL NORTH OF CANADA. SATELLITE AND RECONNAISSANCE AIRCRAFT FIXES INDICATE THAT THE INITIAL MOTION IS TOWARD THE NORTHWEST OR 320 DEGREES AT 15 KNOTS. THE SUBTROPICAL RIDGE THAT HAS BEEN STEERING EARL TOWARD THE NORTHWEST IS ALREADY SHIFTING EASTWARD...AND LATER TODAY...EARL SHOULD BE ON THE WESTERN SIDE OF THE RIDGE TURNING GRADUALLY NORTHWARD. IN 36 HOURS OR SO...THE HURRICANE WILL ENCOUNTER THE BASE OF THE MID-LATITUDE WESTERLIES AND SHOULD BEGIN TO RECURVE OR TURN TO THE NORTHEAST WITH AN INCREASING FORWARD SPEED. THIS IS THE SOLUTION UNANIMOUSLY PROVIDED BY TRACK MODELS...WHICH HAVE EARL PASSING TO THE EAST BUT NOT FAR FROM THE OUTER BANKS OF NORTH CAROLINA BETWEEN 36 AND 48 HOURS. ONLY A SMALL WESTWARD DEVIATION TO THE TRACK TO THE WEST WOULD BRING THE CORE OF THE HURRICANE TO THE COAST. GIVEN THE FORECAST TRACK AND THE LARGE WIND RADII ASSOCIATED WITH A EARL...A HURRICANE WARNING WAS REQUIRED FOR A PORTION OF THE NORTH CAROLINA COAST. FORECAST POSITIONS AND MAX WINDS INITIAL 01/1500Z 25.1N 72.1W 110 KT 12HR VT 02/0000Z 27.0N 73.7W 110 KT 24HR VT 02/1200Z 29.8N 75.0W 110 KT 36HR VT 03/0000Z 32.8N 75.2W 110 KT 48HR VT 03/1200Z 36.0N 73.6W 100 KT 72HR VT 04/1200Z 44.0N 66.0W 70 KT 96HR VT 05/1200Z 55.0N 60.0W 50 KT...POST-TROP/EXTRATROP 120HR VT 06/1200Z...ABSORBED BY A LARGER EXTRATROPICAL CYCLONE $$ FORECASTER AVILA WTNT42 KNHC 012051 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 30 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM EDT WED SEP 01 2010 VISIBLE SATELLITE IMAGES INDICATE THAT THE EYE HAS BECOME VERY DISTINCT...WITH OJECTIVE T-NUMBERS OSCILLATING AROUND 6.0 FOR THE PAST FEW HOURS. AN AIR FORCE PLANE MEASURED FLIGHT-LEVEL WINDS OF 138 KNOTS AND A MINIMUM PRESSURE OF 941 MB IN THE LAST FIX. HOWEVER...SFMR MEASUREMENTS WERE A LITTLE LOWER. A COMPROMISE OF THESE DATA SUPPORTS AN INITIAL INTENSITY OF 115 KNOTS. HOWEVER...EARL COULD FLUCTUATE IN INTENSITY DURING THE NEXT 12 TO 24 HOURS BUT SHOULD BEGIN TO GRADUALLY WEAKEN AS IT REACHES COOLER WATERS AND MOVES INTO HIGHER SHEAR BEYOND 36 HOURS. BY DAY 5 THE HURRICANE SHOULD HAVE BEEN ABSORBED BY A LARGE EXTRATROPICAL CYCLONE WELL NORTH OF CANADA. SATELLITE AND RECONNAISSANCE AIRCRAFT FIXES INDICATE THAT EARL HAS BEEN MOVING RELENTLESSLY TOWARD THE NORTHWEST OR 310 DEGREES AT 15 KNOTS. THE HURRICANE IS ABOUT TO REACH THE WESTERN EDGE OF THE SUBTROPICAL RIDGE AND SHOULD BEGIN TO TURN MORE TO THE NORTH-NORTHWEST AND NORTH LATER TONIGHT AND THURSDAY. IN ABOUT 36 HOURS OR SO...THE HURRICANE WILL ENCOUNTER THE BASE OF THE MID-LATITUDE WESTERLIES AND SHOULD BEGIN TO RECURVE OR TURN TO THE NORTHEAST WITH AN INCREASING FORWARD SPEED. THIS IS THE SOLUTION CONSISTENTLY PROVIDED BY TRACK MODELS...WHICH HAVE EARL PASSING TO THE EAST BUT NOT FAR FROM THE OUTER BANKS OF NORTH CAROLINA ON THURSDAY NIGHT. ONLY A SMALL WESTWARD DEVIATION OF THE TRACK TO THE WEST WOULD BRING THE CORE OF THE HURRICANE TO THE COAST. GIVEN THE FORECAST TRACK...THE LARGE SIZE OF THE WIND FIELD...AND THE EXPECTED INCREASE IN FORWARD SPEED WATCHES AND WATCHES HAVE BEEN EXTENDED NORTHWARD ALONG THE EAST COAST OF THE UNITED STATES. FORECAST POSITIONS AND MAX WINDS INITIAL 01/2100Z 26.3N 73.3W 115 KT 12HR VT 02/0600Z 28.4N 74.7W 115 KT 24HR VT 02/1800Z 31.7N 75.4W 110 KT 36HR VT 03/0600Z 35.1N 74.7W 100 KT 48HR VT 03/1800Z 38.5N 72.2W 90 KT 72HR VT 04/1800Z 46.5N 63.5W 60 KT 96HR VT 05/1800Z 58.0N 57.0W 40 KT...POST-TROP/EXTRATROP 120HR VT 06/1800Z...DISSIPATED $$ FORECASTER AVILA WTNT42 KNHC 020259 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 31 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM EDT WED SEP 01 2010 ENHANCED INFRARED SATELLITE IMAGERY SHOWS THAT THE EYE OF EARL HAS BECOME MORE WELL-DEFINED AND THE CLOUD TOPS IN THE EYEWALL HAVE COOLED. A NOAA HURRICANE HUNTER AIRCRAFT INVESTIGATING THE HURRICANE FOUND THAT THE CENTRAL PRESSURE HAS FALLEN SIGNIFICANTLY...AND THEY MEASURED WINDS TO 137 KT JUST NORTH OF THE CENTER AT A FLIGHT LEVEL JUST BELOW 7000 FT. REDUCING THIS WIND SPEED FROM THE AIRCRAFT FLIGHT LEVEL TO THE SURFACE YIELDS ABOUT 120 KT...AND THAT WILL BE THE ADVISORY INTENSITY. SOME FLUCTUATIONS IN INTENSITY DUE TO INNER CORE CHANGES ARE LIKELY ON THURSDAY. EARL SHOULD REMAIN IN A LOW-SHEAR ENVIRONMENT FOR ABOUT ANOTHER 24 HOURS...THEREFORE GRADUAL WEAKENING SHOULD COMMENCE IN A DAY OR SO. HOWEVER...EARL IS LIKELY TO MAINTAIN MAJOR HURRICANE STATUS WHEN IT IS NEAREST TO...OR POSSIBLY OVER...THE OUTER BANKS. THE OFFICIAL INTENSITY FORECAST IS RATHER CLOSE TO THE LATEST STATISTICAL/DYNAMICAL MODEL GUIDANCE. THE EYE OF THE HURRICANE WOBBLED NORTHWARD A COUPLE OF HOURS AGO...HOWEVER THE MEAN MOTION APPEARS TO BE ABOUT 330/16. NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST TRACK OR SYNOPTIC REASONING FROM THE PREVIOUS ADVISORY PACKAGE...ALTHOUGH THE MULTI-MODEL CONSENSUS FORECAST HAS NUDGED EASTWARD ABOUT 20 N MI ON THIS CYCLE. EARL IS EXPECTED TO GRADUALLY TURN TOWARD THE NORTH AND SLIGHTLY EAST OF NORTH AS IT MOVES ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE FOR THE NEXT DAY OR SO. THEREAFTER...A STRONG 500 MB TROUGH MOVING THROUGH THE GREAT LAKES SHOULD CAUSE THE HURRICANE TO TURN TOWARD THE NORTH-NORTHEAST AND ACCELERATE. ONE SHOULD NOT FOCUS ON THE EXACT FORECAST TRACK OF THIS LARGE AND INTENSE HURRICANE. SIGNIFICANT IMPACTS ARE LIKELY TO BE FELT WELL AWAY FROM THE CENTER. FORECAST POSITIONS AND MAX WINDS INITIAL 02/0300Z 27.8N 73.8W 120 KT 12HR VT 02/1200Z 30.0N 75.1W 120 KT 24HR VT 03/0000Z 33.2N 75.2W 110 KT 36HR VT 03/1200Z 36.5N 73.7W 100 KT 48HR VT 04/0000Z 40.0N 70.7W 85 KT 72HR VT 05/0000Z 48.5N 61.5W 55 KT...POST-TROP/EXTRATROP 96HR VT 06/0000Z 57.0N 57.0W 40 KT...POST-TROP/EXTRATROP 120HR VT 07/0000Z...DISSIPATED $$ FORECASTER PASCH WTNT42 KNHC 020907 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 32 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM EDT THU SEP 02 2010 AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT REPORTED 140 KT WINDS AT 700 MB IN THE NORTHEASTERN EYEWALL. AN EYE DROPSONDE REPORTED A SURFACE PRESSURE OF 929 MB WITH A WIND OF 25 KT...SUGGESTING A CENTRAL PRESSURE NEAR 928 MB. BASED ON THIS...THE INITIAL INTENSITY IS INCREASED TO 125 KT. EARL IS LIKELY NEAR PEAK INTENSITY AT THIS TIME...AS THE EYEWALL CONVECTION IS BECOMING A LITTLE LESS ORGANIZED IN SATELLITE IMAGERY. THE INITIAL MOTION IS 330/16. THERE IS LITTLE CHANGE TO EITHER THE FORECAST PHILOSOPHY OF THE TRACK FORECAST FOR THE FIRST 48 HR. EARL SHOULD TURN NORTHWARD AND NORTH-NORTHEASTWARD AS IT ROUNDS THE END OF THE SUBTROPICAL RIDGE AND ENTERS THE WESTERLIES. THE TRACK MODEL GUIDANCE IS TIGHTLY CLUSTERED AROUND THIS SOLUTION...AND THE NEW TRACK IS DOWN THE MIDDLE OF THE CLUSTER. AFTER 48 HR...THE GUIDANCE HAS SHIFTED TO THE LEFT DUE TO CHANGES IN THE INTERACTION OF EARL WITH A STRONG WESTERLY TROUGH DURING EXTRATROPICAL TRANSITION. THE 48-72 HR TRACK HAS BEEN SHIFTED TO THE LEFT...BUT STILL LIES ON THE RIGHT SIDE OF THE GUIDANCE ENVELOPE. THE INTENSITY GUIDANCE SUGGESTS EARL SHOULD MAINTAIN ITS CURRENT INTENSITY FOR 12 HR OR SO. AFTER THAT...INCREASING VERTICAL WIND SHEAR AND MOTION OVER DECREASING SEA SURFACE TEMPERATURES SHOULD CAUSE STEADY WEAKENING. EXTRATROPICAL TRANSITION SHOULD BEGIN AT ABOUT 48 HR AND BE COMPLETE BY 72 HR...WITH THE REMNANTS OF EARL BEING ABSORBED INTO A LARGER BAROCLINIC LOW BY 96 HR. FORECAST POSITIONS AND MAX WINDS INITIAL 02/0900Z 29.3N 74.7W 125 KT 12HR VT 02/1800Z 31.7N 75.3W 125 KT 24HR VT 03/0600Z 34.8N 74.6W 115 KT 36HR VT 03/1800Z 38.1N 72.6W 100 KT 48HR VT 04/0600Z 41.6N 69.2W 85 KT 72HR VT 05/0600Z 50.5N 62.5W 50 KT...POST-TROP/EXTRATROP 96HR VT 06/0600Z...ABSORBED BY EXTRATROPICAL LOW $$ FORECASTER BEVEN WTNT42 KNHC 021456 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 33 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM EDT THU SEP 02 2010 THERE HAS BEEN NO SIGNIFICANT CHANGES IN THE STRUCTURE OF EARL DURING THE PAST FEW HOURS. HOWEVER..MICROWAVE INAGERY SUGGEST THAT AN EYEWALL REPLACEMENT COULD OCCUR SOON...IN WHICH CASE THE WIND FIELD WOULD BECOME LARGER. THE HURRICANE CONTINUES WITH A DISTINCT EYE SURROUNDED BY DEEP CONVECTION. SATELLITE INTENSITY ESTIMATES AND DATA FROM A RECONNAISSANCE AIRCRAFT A FEW HOURS AGO INDICATE THAT THE INITIAL INTENSITY IS 120 KNOTS. EARL PROBABLY HAS ALREADY REACHED ITS PEAK INTENSITY AND IT SHOULD SOON BEGIN TO WEAKEN GRADUALLY AS THE SHEAR INCREASES. THE HURRICANE SHOULD WEAKEN EVEN FASTER AFTER 36 HOURS...AS IT MOVES OVER A COLDER OCEAN. EARL SHOULD BECOME EXTRATROPICAL BY 72 HOURS AND DISSIPATE THEREAFTER AS IT BECOMES ABSORBED BY A MUCH LARGER EXTRATROPICAL CYCLONE. AS ANTICIPATED...EARL HAS BEGUN TO MOVE NORTHWARD OR 355 DEGREES AT 16 KNOTS. SINCE THE STEERING PATTERN HAS NOT CHANGED...EARL IS FORECAST TO CONTINUE NORTHWARD TODAY. IN ABOUT 24 HOURS...THE HURRICANE SHOULD BE ENCOUNTERING THE BASE OF THE MID-LATITUDE WESTERLIES AND EARL SHOULD THEN TURN MORE TOWARD THE NORTH-NORTHEAST AND NORTHEAST WITH AN INCREASE IN FORWARD SPEED. THIS SHARP TURN HAS BEEN CONSISTENTLY INDICATED FOR THE PAST COUPLE OF DAYS IN THE OFFICIAL FORECAST AND BY THE TIGHTLY CLUSTERED TRACK GUIDANCE. FORECAST POSITIONS AND MAX WINDS INITIAL 02/1500Z 30.9N 74.8W 120 KT 12HR VT 03/0000Z 33.5N 75.0W 115 KT 24HR VT 03/1200Z 36.5N 73.5W 100 KT 36HR VT 04/0000Z 40.0N 70.8W 85 KT 48HR VT 04/1200Z 44.0N 67.0W 65 KT 72HR VT 05/1200Z 53.5N 62.0W 40 KT...POST-TROP/EXTRATROP 96HR VT 06/1200Z...ABSORBED BY A LARGE EXTRATROPICAL LOW $$ FORECASTER AVILA WTNT42 KNHC 022039 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 34 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM EDT THU SEP 02 2010 DATA FROM A RECONNAISSANCE PLANE INDICATE THAT EARL HAS WEAKENED A LITTLE BIT THIS AFTERNOON. THE CENTRAL PRESSURE ROSE TO 947 MB...AND A BLEND OF THE SFMR MEASUREMENTS AND FLIGHT-LEVEL WINDS SUGGEST THAT THE INITIAL INTENSITY HAS DECREASED TO 100 KNOTS. EARL SHOULD CONTINUE TO WEAKEN GRADUALLY AS THE SHEAR INCREASES AND THE HURRICANE SHOULD WEAKEN EVEN FASTER AFTER 24 HOURS AS IT MOVES OVER A COLDER OCEAN. AFTER CROSSING CANADA IN 48 HOURS...EARL SHOULD BECOME POST-TROPICAL/EXTRATROPICAL AND THEN DISSIPATE AS IT IS ABSORBED BY A MUCH LARGER EXTRATROPICAL CYCLONE. SATELLITE AND RECONNAISSANCE FIXES SHOW...AS ANTICIPATED...THAT EARL HAS TURNED NORTHWARD AND IS MOVING 360 DEGREES AT 16 KNOTS. THE STEERING PATTERN CONTROLLING THE MOTION OF EARL...AND THE CONSISTENCY IN TRACK GUIDANCE...HAVE BEEN ADEQUATELY DESCRIBED IN PREVIOUS DISCUSSIONS. EARL IS ABOUT TO BECOME EMBEDDED IN THE MID-LATITUDE FLOW AND IT IS READY TO GRADUALLY TURN TO THE NORTH-NORTHEAST AND NORTHEAST WITH AN INCREASE IN FORWARD SPEED. ALTHOUGH THE MAXIMUM WINDS IN THE CORE HAVE DECREASED...EARL CONTINUES TO BE A LARGE AND POWERFUL HURRICANE. FORECAST POSITIONS AND MAX WINDS INITIAL 02/2100Z 32.5N 75.2W 100 KT 12HR VT 03/0600Z 34.8N 74.8W 95 KT 24HR VT 03/1800Z 38.0N 72.7W 85 KT 36HR VT 04/0600Z 41.7N 69.0W 75 KT 48HR VT 04/1800Z 46.5N 64.5W 50 KT...POST-TROP/EXTRATROP 72HR VT 05/1800Z...DISSIPATED $$ FORECASTER AVILA WTNT42 KNHC 030241 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 35 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM EDT THU SEP 02 2010 DATA FROM AIRCRAFT RECONNAISSANCE THIS EVENING SHOW THAT EARL HAS CONTINUED TO SLOWLY WEAKEN...AS THE PRESSURE HAS RISEN TO 951 MB. THE MAXIMUM FLIGHT LEVEL WIND WAS 111 KT...HOWEVER THE HIGHEST SURFACE WIND MEASURED RECENTLY BY THE SFMR WAS 84 KT...AND DROPSONDE DATA ARE CONSISTENT WITH SURFACE WINDS IN THE 80 TO 90 KT RANGE. BASED ON A BLEND OF THESE DATA...THE INITIAL INTENSITY IS SET TO 90 KT FOR THIS ADVISORY. THE AIRCRAFT DATA ALONG WITH MICROWAVE IMAGERY SHOW THAT THE OLD INNER EYEWALL HAS DISSIPATED...AND A LARGER 50 N MI WIDE EYE IS NOW REPORTED BY THE AIRCRAFT AND VISIBLE IN RADAR IMAGERY FROM MOREHEAD CITY. SOUTHWESTERLY SHEAR OF 15 TO 20 KNOTS IS CURRENTLY ANALYZED OVER THE CYCLONE BY UW-CIMSS AND THE SHIPS MODEL...AND OUTFLOW IS NOW RESTRICTED IN THE SOUTHWEST QUADRANT. EARL SHOULD CONTINUE TO SLOWLY WEAKEN AS IT MOVES NORTHWARD OVER COOLER WATERS AND SHEAR INCREASES. MODEL FIELDS AND CYCLONE PHASE SPACE DIAGRAMS SHOW EARL BECOMING EXTRATROPICAL BY 48 HOURS...AND BEING ABSORBED BY A LARGER EXTRATROPICAL CYCLONE BY 72 HOURS. THE OFFICIAL INTENSITY FORECAST HAS BEEN ADJUSTED DOWNWARD SLIGHTLY IN AGREEMENT WITH THE ICON CONSENSUS. SATELLITE AND RECONNAISSANCE FIXES SHOW THAT EARL HAS TURNED TOWARD THE NORTH-NORTHEAST...AND THE INITIAL MOTION ESTIMATE IS 015/15. THE TRACK MODEL GUIDANCE REMAINS TIGHTLY CLUSTERED AND SHOWS AN INCREASE IN FORWARD SPEED AND A TURN TOWARD THE NORTHEAST IN THE NEXT 24 TO 36 HOURS AS EARL IS CAPTURED BY A LARGE MID- TO UPPER- LEVEL TROUGH MOVING INTO EASTERN NORTH AMERICA. BASED ON THE INITIAL POSITION AND MOTION...THE TRACK FORECAST HAS BEEN ADJUSTED A LITTLE TO THE EAST OF THE PREVIOUS PACKAGE...BUT LIES ON THE LEFT SIDE OF THE GUIDANCE SUITE. LATER FORECASTS MAY BE ADJUSTED FARTHER EASTWARD IF THE CURRENT MOTION TO THE EAST OF DUE NORTH CONTINUES. ALTHOUGH THE MAXIMUM WINDS IN THE CORE HAVE DECREASED...EARL CONTINUES TO BE A LARGE HURRICANE AND AIRCRAFT DATA SHOW THAT THE WIND FIELD HAS EXPANDED SOMEWHAT IN THE WESTERN SEMICIRCLE. EARL IS EXPECTED TO PRODUCE TROPICAL-STORM-FORCE WINDS OVER A LARGE PORTION OF THE MID-ATLANTIC AND NEW ENGLAND COASTS...AND NEW TROPICAL STORM WARNINGS HAVE BEEN ISSUED FOR PORTIONS OF THE COAST OF MASSACHUSETTS AND MAINE. FORECAST POSITIONS AND MAX WINDS INITIAL 03/0300Z 33.8N 74.4W 90 KT 12HR VT 03/1200Z 36.2N 73.7W 85 KT 24HR VT 04/0000Z 39.5N 70.7W 80 KT 36HR VT 04/1200Z 43.9N 66.5W 70 KT 48HR VT 05/0000Z 48.4N 61.5W 50 KT...POST-TROP/EXTRATROP 72HR VT 06/0000Z...DISSIPATED $$ FORECASTER BRENNAN WTNT42 KNHC 030911 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 36 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM EDT FRI SEP 03 2010 EARL CONTINUES TO SLOWLY WEAKEN...WITH THE EYE BECOMING INDISTINCT IN BOTH SATELLITE AND RADAR DATA. AN AIR FORCE RESERVE HURRICANE HUNTER REPORTED A CENTRAL PRESSURE OF 955 MB AT ABOUT 05Z. THE MAXIMUM 700 MB FLIGHT-LEVEL WINDS AT 03Z WERE 118 KT...WHILE THE MAXIMUM SFMR WINDS NEAR THAT TIME WERE 83 KT. A BLEND OF THESE DATA IS USED FOR THE INITIAL INTENSITY OF 90 KT. EARL SHOULD CONTINUE TO WEAKEN THROUGH 36 HR DUE TO INCREASING VERTICAL WIND SHEAR AND COOLER SEA SURFACE TEMPERATURES. HOWEVER...IT IS STILL FORECAST TO BE A HURRICANE AS IT PASSES NEAR OR OVER SOUTHEASTERN NEW ENGLAND AND NOVA SCOTIA. THE CYCLONE IS FORECAST TO BECOME EXTRATROPICAL BY 48 HR...AND TO BE ABSORBED BY A LARGER EXTRATROPICAL LOW BY 72 HR. THE INITIAL MOTION IS 015-020 AT ABOUT 16 KT. ALL GUIDANCE AGREES THAT EARL SHOULD TURN NORTHEASTWARD AND ACCELERATE DURING THE NEXT 12-24 HOURS...AND THE NHC FORECAST FOLLOWS THIS SCENARIO. A TURN MORE TO THE NORTH-NORTHEAST IS POSSIBLE AFTER 36 HR AS EARL UNDERGOES EXTRATROPICAL TRANSITION. THE NEW FORECAST TRACK IS DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE AND IS SIMILAR TO THE PREVIOUS FORECAST. IT SHOULD BE NOTED THAT THE UKMET CONTINUES TO FORECAST EARL TO MAKE LANDFALL NEAR CAPE COD...AND ANY MOTION TO THE LEFT OF THE FORECAST TRACK COULD ALLOW THIS TO HAPPEN. ALTHOUGH THE MAXIMUM WINDS IN THE CORE ARE DECREASING...EARL CONTINUES TO BE A LARGE HURRICANE WITH THE WIND RADII EXPANDED IN THE SOUTHEASTERN QUADRANT BASED ON ASCAT DATA. THE CYCLONE IS EXPECTED TO PRODUCE TROPICAL-STORM-FORCE WINDS OVER A LARGE PORTION OF THE MID-ATLANTIC AND NEW ENGLAND COASTS. FORECAST POSITIONS AND MAX WINDS INITIAL 03/0900Z 35.3N 74.0W 90 KT 12HR VT 03/1800Z 37.8N 72.4W 85 KT 24HR VT 04/0600Z 41.6N 68.9W 75 KT 36HR VT 04/1800Z 45.9N 64.3W 55 KT 48HR VT 05/0600Z 50.7N 60.0W 45 KT...POST-TROP/EXTRATROP 72HR VT 06/0600Z...DISSIPATED $$ FORECASTER BEVEN WTNT42 KNHC 031459 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 37 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM EDT FRI SEP 03 2010 SATELLITE IMAGES AND DATA FROM AN AIR FORCE RECONNAISSANCE PLANE INDICATE THAT EARL HAS CONTINUED TO WEAKEN. THE INITIAL INTENSITY HAS BEEN REDUCED TO 75 KNOTS. THE HURRICANE IS ALREADY MOVING OVER INCREASINGLY COOLER WATERS AND A CONTINUED WEAKENING IS ANTICIPATED. HOWEVER...EARL IS FORECAST TO PASS NEAR CAPE COD AS A HURRICANE WITH A LARGE AREA OF TROPICAL STORM FORCE WINDS WHICH SHOULD AFFECT A LARGE PORTION OF THE MID-ATLANTIC AND NEW ENGLAND COASTS. EARL SHOULD REACH CANADA AS A STRONG TROPICAL STORM AND THEN BECOME EXTRATROPICAL IN ABOUT 36 HOURS. EARL IS MOVING TOWARD THE NORTH-NORTHEAST OR 030 DEGREES AT 18 KNOTS. THE HURRICANE HAS ALREADY RECURVED WHILE EMBEDDED IN THE SOUTHWESTERLY FLOW AHEAD OF AN APPROACHING MID-LATITUDE TROUGH. EARL SHOULD CONTINUE ON THIS GENERAL TRACK WITH AN INCREASE IN FORWARD SPEED UNTIL DISSIPATION IN A FEW DAYS. FORECAST POSITIONS AND MAX WINDS INITIAL 03/1500Z 36.8N 73.1W 75 KT 12HR VT 04/0000Z 39.7N 70.8W 70 KT 24HR VT 04/1200Z 43.8N 66.5W 60 KT 36HR VT 05/0000Z 49.0N 62.0W 45 KT...POST-TROP/EXTRATROP 48HR VT 05/1200Z 52.0N 56.5W 45 KT...POST-TROP/EXTRATROP 72HR VT 06/1200Z...DISSIPATED $$ FORECASTER AVILA WTNT42 KNHC 032037 TCDAT2 HURRICANE EARL DISCUSSION NUMBER 38 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM EDT FRI SEP 03 2010 EARL HAS BEEN MOVING OVER COOLER WATER AND WEAKENING. BASED ON THE SATELLITE PRESENTATION AND EARLIER RECONNAISSANCE DATA...THE INITIAL INTENSITY HAS BEEN LOWERED TO 70 KNOTS. ALTHOUGH CONTINUED WEAKENING IS ANTICIPATED...EARL IS FORECAST TO PASS NEAR CAPE COD AS A HURRICANE WITH A LARGE AREA OF TROPICAL STORM FORCE WINDS. THESE WINDS WILL LIKELY AFFECT A LARGE PORTION OF THE MID-ATLANTIC AND NEW ENGLAND COASTS. EARL IS EXPECTED TO REACH CANADA AS A STRONG TROPICAL STORM AND THEN BECOME EXTRATROPICAL IN ABOUT 36 HOURS. EARL IS STILL MOVING TOWARD THE NORTH-NORTHEAST OR 030 DEGREES AT 18 KNOTS...BUT IT SHOULD SOON INCREASE ITS FORWARD SPEED. THE HURRICANE HAS ALREADY RECURVED WHILE EMBEDDED IN THE SOUTHWESTERLY FLOW AHEAD OF AN APPROACHING MID-LATITUDE TROUGH. EARL SHOULD CONTINUE ON THIS GENERAL TRACK WITH AN INCREASE IN FORWARD SPEED UNTIL DISSIPATION IN 36 TO 48 HOURS. FORECAST POSITIONS AND MAX WINDS INITIAL 03/2100Z 38.2N 71.8W 70 KT 12HR VT 04/0600Z 41.2N 69.2W 60 KT 24HR VT 04/1800Z 46.5N 64.0W 50 KT 36HR VT 05/0600Z 51.5N 59.0W 40 KT...POST-TROP/EXTRATROP 48HR VT 05/1800Z...ABSORBED BY A LARGE EXTRATROPICAL LOW $$ FORECASTER AVILA WTNT42 KNHC 040239 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 39 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM EDT FRI SEP 03 2010 EARL HAS CONTINUED TO SLOWLY WEAKEN THIS EVENING. WHILE THE CENTRAL PRESSURE REMAINS 958 MB...AIRCRAFT DATA SUGGEST THAT EARL IS NOW BELOW HURRICANE STRENGTH. THE INITIAL INTENSITY OF 60 KT IS BASED ON A BLEND OF PEAK SFMR VALUES OF AROUND 55 KT AND A 700-MB FLIGHT LEVEL WIND MAXIMUM OF 67 KT JUST PRIOR TO 0000 UTC. THE DEEP CONVECTION WITH EARL IS INCREASINGLY LIMITED TO THE NORTHERN SEMICIRCLE OF THE CIRCULATION...DUE TO SOUTHERLY WIND SHEAR OF 15-20 KT AND DRY AIR ADVECTION SOUTH OF THE CENTER. EARL WILL BE CROSSING THE NORTHERN WALL OF THE GULF STREAM SOON...AND COLD WATER AND INCREASING SHEAR SHOULD RESULT IN CONTINUED WEAKENING UNTIL EXTRATROPICAL TRANSITION BEGINS. GLOBAL MODEL FIELDS AND PHASE SPACE DIAGRAMS SUGGEST THAT EARL WILL BE UNDERGOING EXTRATROPICAL TRANSITION BY 24 HOURS...WITH THE TRANSITION COMPLETE IN 36 HOURS. THE INITIAL MOTION ESTIMATE IS TOWARD THE NORTHEAST...OR 035 DEGREES AT 22 KNOTS. EARL SHOULD CONTINUE TO ACCELERATE AHEAD OF A LARGE MID- TO UPPER-LEVEL TROUGH MOVING EASTWARD FROM THE GREAT LAKES INTO SOUTHEASTERN CANADA OVER THE NEXT COUPLE OF DAYS. BEYOND THAT TIME...MUCH OF THE GLOBAL MODEL GUIDANCE NOW SUGGESTS THAT EARL WILL TURN NORTHWARD AND THEN NORTHWESTWARD AS A DISTINCT CYCLONE THROUGH 72 HOURS BEFORE DISSIPATING OR BEING ABSORBED. THE EXTRATROPICAL PORTION OF THE TRACK IS BASED ON COORDINATION WITH THE OCEAN PREDICTION CENTER. EARL REMAINS A LARGE TROPICAL CYCLONE...AND WILL BRING HIGH WINDS AND RAINFALL TO MUCH OF COASTAL NEW ENGLAND AND THE CANADIAN MARITIMES OVERNIGHT TONIGHT AND SATURDAY. FORECAST POSITIONS AND MAX WINDS INITIAL 04/0300Z 40.0N 69.7W 60 KT 12HR VT 04/1200Z 43.1N 66.6W 55 KT 24HR VT 05/0000Z 48.2N 61.6W 45 KT...POST-TROPICAL 36HR VT 05/1200Z 52.5N 56.5W 45 KT...POST-TROP/EXTRATROP 48HR VT 06/0000Z 55.5N 54.0W 40 KT...POST-TROP/EXTRATROP 72HR VT 07/0000Z 57.0N 57.0W 40 KT...POST-TROP/EXTRATROP 96HR VT 08/0000Z...DISSIPATED $$ FORECASTER BRENNAN WTNT42 KNHC 040856 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 40 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 AM EDT SAT SEP 04 2010 BOTH DOPPLER RADAR AND SATELLITE IMAGERY INDICATE THAT DURING THE PAST FEW HOURS EARL HAS DEVELOPED A RING OF SHALLOW TO MODERATE CONVECTION AROUND THE CENTER...WHICH RESEMBLES AN EYEWALL. BASED ON THE LAST RECON DATA...LITTLE CHANGE NOTED IN THE OVERALL STRUCTURE OF THE CYCLONE...AND THE FASTER FORWARD SPEED...THE INITIAL INTENSITY WILL REMAIN AT 60 KT FOR THIS ADVISORY. THE INITIAL MOTION ESTIMATE IS 045/26. THERE IS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK AND INTENSITY REASONINGS. EARL IS EMBEDDED WITHIN SOUTHWESTERLY FLOW AHEAD OF A DEEP LAYER TROUGH THAT IS MOVING EASTWARD ACROSS THE GREAT LAKES AREA AND INTO THE NORTHEASTERN UNITED STATES. THE CYCLONE IS FORECAST TO CONTINUE MOVING NORTHEASTWARD AND SLOWLY WEAKEN AS IT MOVES OVER MUCH COOLER WATER AND INTERACTS WITH THE CANADIAN MARITIMES LANDMASSES. HOWEVER...EARL IS STILL EXPECTED TO REMAIN A VERY LARGE AND STRONG EXTRATROPICAL LOW PRESSURE SYSTEM AFTER IT PASSES NORTH OF NOVA SCOTIA LATER TODAY. THE OFFICIAL FORECAST TRACK IS A LITTLE TO THE RIGHT OF THE PREVIOUS ADVISORY TRACK...AND IS CLOSE TO THE MODEL CONSENSUS. THE EXTRATROPICAL PORTION OF THE TRACK IS BASED ON COORDINATION WITH THE NOAA OCEAN PREDICTION CENTER. EARL REMAINS A LARGE TROPICAL CYCLONE...AND WILL BRING HIGH WINDS AND RAINFALL TO EASTERN NEW ENGLAND THIS MORNING...AND TO THE CANADIAN MARITIMES THIS AFTERNOON AND EVENING. FORECAST POSITIONS AND MAX WINDS INITIAL 04/0900Z 41.7N 67.1W 60 KT 12HR VT 04/1800Z 45.4N 63.3W 55 KT...INLAND 24HR VT 05/0600Z 50.1N 58.8W 45 KT...POST-TROP/EXTRATROP 36HR VT 05/1800Z 54.0N 55.0W 45 KT...POST-TROP/EXTRATROP 48HR VT 06/0600Z 56.0N 53.5W 40 KT...POST-TROP/EXTRATROP 72HR VT 07/0600Z 56.5N 55.0W 35 KT...POST-TROP/EXTRATROP 96HR VT 08/0600Z...DISSIPATED $$ FORECASTER STEWART WTNT42 KNHC 041449 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 41 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 AM EDT SAT SEP 04 2010 EARL HAS MAINTAINED SOME CIRCULAR CONVECTIVE STRUCTURE ON SATELLITE IMAGERY INDICATING THAT IT IS STILL A TROPICAL CYCLONE. HOWEVER...MOST THE RAIN SHIELD HAS BEGUN TO SHIFT TOWARD THE NORTHWESTERN PORTION OF THE CIRCULATION...AND THE WIND FIELD IS EXPANDING ON THE SOUTH SIDE. THIS SUGGESTS THAT EARL IS GRADUALLY BEGINNING TO ACQUIRE SOME EXTRATROPICAL CHARACTERISTICS. BEST ESTIMATE OF THE INITIAL INTENSITY IS 60 KNOTS...BASED ON SURROUNDING SURFACE DATA. EARL IS EXPECTED TO BECOME EXTRATROPICAL IN ABOUT 24 HOURS AND SHOULD CONTINUE AS A LARGE EXTRATROPICAL CYCLONE FOR 2 TO 3 DAYS. EARL HAS CONTINUED TO INCREASE ITS FORWARD SPEED AND IS NOW MOVING TOWARD THE NORTHEAST OF 035 DEGREES AT 30 KNOTS. THIS GENERAL TRACK WITH A DECREASE IN FORWARD SPEED IS EXPECTED DURING THE NEXT DAY OR SO. FORECAST POSITIONS AND MAX WINDS INITIAL 04/1500Z 44.3N 64.5W 60 KT 12HR VT 05/0000Z 48.0N 60.7W 50 KT...OVER WATER 24HR VT 05/1200Z 52.5N 56.0W 45 KT...POST-TROP/EXTRATROP 36HR VT 06/0000Z 55.5N 53.5W 40 KT...POST-TROP/EXTRATROP 48HR VT 06/1200Z 57.0N 54.0W 40 KT...POST-TROP/EXTRATROP 72HR VT 07/1200Z 56.0N 53.0W 40 KT...POST-TROP/EXTRATROP 96HR VT 08/1200Z...ABSORBED $$ FORECASTER AVILA WTNT42 KNHC 042033 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 42 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 500 PM EDT SAT SEP 04 2010 LARGE TROPICAL CYCLONE EARL HAS BEEN MOVING TOWARD THE NORTH-NORTHEAST AT ABOUT 35 KNOTS PRODUCING SUSTAINED TROPICAL STORM FORCE WINDS OVER MUCH OF THE CANADIAN MARITIMES. THE CYCLONE IS BECOMING A LITTLE BIT ASYMMETRIC AND THE WIND FIELD IS EXPANDING...BUT THERE IS PLENTY OF ORGANIZED CONVECTION NEAR THE CENTER FOR SUCH A HIGH LATITUDE CYCLONE. THIS MEANS THAT EARL STILL IS RETAINING ITS TROPICAL CHARACTERISTICS. THE CYCLONE IS FORECAST TO MOVE OVER THE COLD WATERS OF THE GULF OF SAINT LAWRENCE AND BECOME POST-TROPICAL LATER TONIGHT. FORECAST POSITIONS AND MAX WINDS INITIAL 04/2100Z 47.5N 62.2W 60 KT 12HR VT 05/0600Z 52.0N 58.5W 45 KT...POST-TROP/EXTRATROP 24HR VT 05/1800Z 55.0N 55.0W 40 KT...POST-TROP/EXTRATROP 36HR VT 06/0600Z 55.7N 51.0W 40 KT...POST-TROP/EXTRATROP 48HR VT 06/1800Z 57.0N 51.0W 35 KT...POST-TROP/EXTRATROP 72HR VT 07/1800Z...DISSIPATED $$ FORECASTER AVILA WTNT42 KNHC 050235 TCDAT2 TROPICAL STORM EARL DISCUSSION NUMBER 43 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072010 1100 PM EDT SAT SEP 04 2010 OVER THE PAST FEW HOURS THE WIND FIELD OF EARL HAS BECOME INCREASINGLY ELONGATED AND THE STRONGEST WINDS ARE NOW WELL REMOVED FROM THE CENTER. DRY AIR ASSOCIATED WITH THE LARGE UPPER TROUGH INTERACTING WITH EARL HAS BEEN ENTRAINED THROUGH THE SOUTHERN SEMICIRCLE OF THE CYCLONE. ALSO...THE EASTERN PORTION OF EARL/S CIRCULATION IS NOW INVOLVED WITH A FRONTAL ZONE. BASED ON ALL OF THIS...EARL IS NOW DECLARED POST-TROPICAL...AND THIS WILL BE THE LAST NHC ADVISORY ON EARL. THE INITIAL INTENSITY IS HELD AT 55 KT BASED ON SURFACE OBSERVATIONS. WEAKENING IS EXPECTED AS EARL COMPLETES THE EXTRATROPICAL TRANSITION PROCESS. THE FORWARD SPEED HAS CONTINUED TO INCREASE...AND IS NOW 030/40. THE GLOBAL MODELS ARE IN RELATIVELY GOOD AGREEMENT ON THE TRACK OF POST-TROPICAL EARL NORTHEASTWARD ACROSS LABRADOR AND INTO THE ATLANTIC OVER THE NEXT DAY OR SO. EARL WILL THEN MOVE SLOWLY NORTHWARD AND NORTHWESTWARD FOR A COUPLE OF DAYS AS IT BECOMES A VERTICALLY STACKED COLD CORE CYCLONE BEFORE ACCELERATING EASTWARD ACROSS THE NORTH ATLANTIC AND DISSIPATING IN 4 OR 5 DAYS. THE OFFICIAL FORECAST IS BASED ON A BLEND OF THE GFS AND ECMWF. EARL IS STILL PRODUCING TROPICAL STORM CONDITIONS OVER PORTIONS OF ATLANTIC CANADA. FOR FURTHER INFORMATION ON POST-TROPICAL EARL IN CANADA...SEE PRODUCTS FROM ENVIRONMENT CANADA. ADDITIONAL INFORMATION ON POST-TROPICAL EARL CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC. FORECAST POSITIONS AND MAX WINDS INITIAL 05/0300Z 50.7N 59.2W 55 KT...POST-TROPICAL 12HR VT 05/1200Z 52.9N 55.4W 40 KT...POST-TROP/EXTRATROP 24HR VT 06/0000Z 55.0N 52.0W 35 KT...POST-TROP/EXTRATROP 36HR VT 06/1200Z 57.0N 53.0W 35 KT...POST-TROP/EXTRATROP 48HR VT 07/0000Z 57.0N 55.0W 35 KT...POST-TROP/EXTRATROP 72HR VT 08/0000Z 54.0N 50.0W 35 KT...POST-TROP/EXTRATROP 96HR VT 09/0000Z 52.0N 36.0W 25 KT...POST-TROP/EXTRATROP 120HR VT 10/0000Z...DISSIPATED $$ FORECASTER BRENNAN