1WTNT45 KNHC 221452 2TCDAT5 3 4TROPICAL DEPRESSION TEN DISCUSSION NUMBER 1 5NWS NATIONAL HURRICANE CENTER MIAMI FL AL102012 61100 AM AST WED AUG 22 2012 7 8SATELLITE DATA INDICATE THAT THE LOW PRESSURE AREA LOCATED OVER THE 9EASTERN TROPICAL ATLANTIC HAS DEVELOPED A WELL-DEFINED SURFACE 10CIRCULATION AND SUFFICIENT CONVECTIVE ORGANIZATION TO BE DESIGNATED 11AS A TROPICAL DEPRESSION. SATELLITE INTENSITY ESTIMATES FROM TAFB 12AND SAB ARE BOTH 2.0...AND THE INITIAL INTENSITY IS SET AT 30KT. 13GIVEN THE FAVORABLE UPPER-AIR ENVIRONMENT AHEAD OF THE DEPRESSION 14DURING THE NEXT 2-3 DAYS...SOME INTENSIFICATION IS EXPECTED. AFTER 15THAT TIME...THE INTENSITY WILL DEPEND IN LARGE PART ON HOW MUCH THE 16DEPRESSION BECOMES INVOLVED WITH AN UPPER-LEVEL LOW NORTHEAST OF 17THE LESSER ANTILLES IN ABOUT 3 DAYS AND THE INFLUENCE OF THE 18UPPER-LEVEL OUTFLOW FROM TROPICAL STORM ISAAC LATE IN THE FORECAST 19PERIOD. INTERACTIONS WITH EITHER WOULD RESULT IN AN INCREASE OF 20VERTICAL WIND SHEAR OVER THE CYCLONE AND A POSSIBLE HALT IN 21INTENSIFICATION. FOR NOW...THE OFFICIAL FORECAST FOLLOWS THE 22INTENSITY CONSENSUS AIDS. 23 24THE INITIAL MOTION ESTIMATE IS 295/14. THE DEPRESSION IS EXPECTED 25TO CONTINUE MOVING WEST-NORTHWESTWARD...NEARLY IN TANDEM WITH A 26MID- TO UPPER-LEVEL IMPULSE ON THE SOUTH SIDE OF A SUBTROPICAL 27RIDGE OVER EASTERN/CENTRAL ATLANTIC. AFTER ABOUT 3 DAYS...THE 28CYCLONE SHOULD TURN NORTHWESTWARD AS IT REACHES THE WESTERN 29PERIPHERY OF THE SUBTROPICAL RIDGE. THE SPREAD IN THE TRACK 30GUIDANCE INCREASES CONSIDERABLY BY THE END OF THE FORECAST 31PERIOD...WITH THE GFS FORECASTING A DEEPER SYSTEM THAT TURNS 32MORE QUICKLY. THE HWRF SHOWS A SHALLOWER VORTEX THAT MOVES ON A 33MORE WESTWARD TRACK. THE OFFICIAL FORECAST LIES BETWEEN THESE TWO 34EXTREMES...CLOSE TO THE ECMWF AND THE MODEL CONSENSUS TVCA. 35 36 37FORECAST POSITIONS AND MAX WINDS 38 39INIT 22/1500Z 12.4N 36.3W 30 KT 35 MPH 40 12H 23/0000Z 13.3N 38.1W 40 KT 45 MPH 41 24H 23/1200Z 14.3N 40.8W 45 KT 50 MPH 42 36H 24/0000Z 15.2N 43.6W 50 KT 60 MPH 43 48H 24/1200Z 16.2N 46.3W 55 KT 65 MPH 44 72H 25/1200Z 18.5N 52.0W 55 KT 65 MPH 45 96H 26/1200Z 21.8N 58.0W 55 KT 65 MPH 46120H 27/1200Z 26.0N 64.0W 60 KT 70 MPH 47 48$$ 49FORECASTER KIMBERLAIN/ZELINSKY 50 51 52WTNT45 KNHC 222041 53TCDAT5 54 55TROPICAL DEPRESSION TEN DISCUSSION NUMBER 2 56NWS NATIONAL HURRICANE CENTER MIAMI FL AL102012 57500 PM AST WED AUG 22 2012 58 59SATELLITE IMAGERY INDICATES THAT TROPICAL DEPRESSION TEN HAS NOT 60BECOME ANY BETTER ORGANIZED...AND CLOUD TOPS ARE WARMING...POSSIBLY 61COINCIDING WITH THE DIURNAL MINIMUM. FURTHERMORE...THE LOW-LEVEL 62CENTER HAS BEEN DIFFICULT TO LOCATE AND MAY BE SOMEWHAT ELONGATED. 63SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB REMAIN AT 2.0...AND 64THE INITIAL INTENSITY IS HELD AT 30 KT. 65 66THE TROPICAL CYCLONE CONTINUES TO MOVE TO THE WEST-NORTHWEST...AND 67THE INITIAL MOTION ESTIMATE IS 295/14...HOWEVER THIS IS HIGHLY 68UNCERTAIN DUE TO DIFFICULTY IN LOCATING THE LOW-LEVEL CENTER. THIS 69GENERAL MOTION IS EXPECTED TO CONTINUE AS THE DEPRESSION MOVES 70TOWARD A MID- TO UPPER-LEVEL WEAKNESS IN THE SUBTROPICAL RIDGE OVER 71THE NEXT 3 DAYS. AFTER THAT TIME...A TURN TO THE NORTHWEST IS 72EXPECTED AS A DEEP-LAYER TROUGH OVER THE EASTERN U.S. CAUSES THE 73RIDGE TO RETREAT AND THE TROPICAL CYCLONE REACHES THE EDGE OF THE 74RIDGE. THE TRACK HAS BEEN ADJUSTED SLIGHTLY TO THE RIGHT...AND IS 75CLOSE TO THE ECMWF AND THE DYNAMICAL MODEL CONSENSUS. 76 77THE UPPER-LEVEL OUTFLOW FROM TROPICAL STORM ISAAC...AND THE FLOW 78ASSOCIATED WITH AN UPPER-LEVEL TROUGH LOCATED OVER THE CENTRAL NORTH 79ATLANTIC...ARE DISTORTING THE OUTFLOW OF TROPICAL DEPRESSION NINE 80INTO A NORTH-SOUTH ORIENTATION. IN THE SHORT TERM...THE VERTICAL 81WIND SHEAR IS FORECAST TO REMAIN SOMEWHAT WEAK OVER THE SYSTEM. BY 82DAY THREE THE TROPICAL CYCLONE IS EXPECTED TO CATCH UP TO THE 83UPPER-LEVEL LOW...WHICH SHOULD RESULT IN A SUBSTANTIAL INCREASE IN 84WIND SHEAR...AND A HALTING OF INTENSIFICATION. THE SHEAR MAY 85DECREASE BY THE END OF THE FORECAST PERIOD AS THE CYCLONE BEGINS TO 86MOVE AWAY FROM THE UPPER LOW. THE NHC INTENSITY FORECAST HAS BEEN 87LOWERED SLIGHTLY...IN LARGE PART DUE TO THE CURRENT ORGANIZATION OF 88THE STORM...AND IS CLOSE TO THE DECAY SHIPS AND LGEM MODELS. 89 90FORECAST POSITIONS AND MAX WINDS 91 92INIT 22/2100Z 13.1N 37.4W 30 KT 35 MPH 93 12H 23/0600Z 14.0N 39.6W 40 KT 45 MPH 94 24H 23/1800Z 15.0N 42.2W 45 KT 50 MPH 95 36H 24/0600Z 16.0N 44.9W 45 KT 50 MPH 96 48H 24/1800Z 17.1N 47.5W 50 KT 60 MPH 97 72H 25/1800Z 19.9N 53.6W 50 KT 60 MPH 98 96H 26/1800Z 23.5N 59.5W 55 KT 65 MPH 99120H 27/1800Z 28.5N 64.5W 60 KT 70 MPH 100 101$$ 102FORECASTER KIMBERLAIN/ZELINSKY 103 104 105WTNT45 KNHC 230233 106TCDAT5 107 108TROPICAL DEPRESSION TEN DISCUSSION NUMBER 3 109NWS NATIONAL HURRICANE CENTER MIAMI FL AL102012 1101100 PM AST WED AUG 22 2012 111 112TROPICAL DEPRESSION TEN HAS BEEN PRODUCING PULSES OF DEEP CONVECTION 113DURING THE PAST FEW HOURS...AND RECENT MICROWAVE IMAGERY SUGGESTS 114THAT THE LOW-LEVEL CLOUD PATTERN REMAINS SOMEWHAT DISORGANIZED. 115DVORAK CI NUMBERS ARE UNCHANGED AT 2.0 FROM TAFB AND SAB...AND THE 116CYCLONE IS STILL BEING DESIGNATED AS A 30-KT DEPRESSION. 117 118WATER VAPOR IMAGERY SUGGESTS THAT THE ROAD AHEAD IS SOMEWHAT OF AN 119OBSTACLE COURSE. THE DEPRESSION IS NOT TOO FAR FROM AN UPPER-LEVEL 120LOW LOCATED TO ITS NORTHWEST...AND IT IS LIKELY TO INTERACT WITH 121THIS FEATURE IN SOME FASHION FOR THE NEXT SEVERAL DAYS. EVEN AFTER 122THE DEPRESSION MOVES AWAY FROM THE UPPER-LOW ON DAYS 4 AND 5...THE 123CYCLONE COULD THEN BE AFFECTED BY THE UPPER-LEVEL OUTFLOW OF 124TROPICAL STORM ISAAC TO ITS WEST. THE DYNAMICAL GFDL AND HWRF 125MODELS HAVE NEVER SHOWN MUCH STRENGTHENING WITH THIS CYCLONE...AND 126THE STATISTICAL SHIPS AND LGEM MODELS HAVE COME DOWN CONSIDERABLY 127ON THIS FORECAST CYCLE. THE NHC INTENSITY FORECAST HAS BEEN 128ADJUSTED DOWNWARD FROM THE PREVIOUS ONE...LYING JUST ABOVE THE 129GUIDANCE FOR THE FIRST 48 HOURS AND THEN VERY NEAR THE INTENSITY 130CONSENSUS FOR DAYS 3 THROUGH 5. 131 132THE DEPRESSION IS LOCATED TO THE SOUTH OF THE SUBTROPICAL RIDGE AND 133HAS AN ESTIMATED MOTION OF 295/15 KT. THE CYCLONE SHOULD CONTINUE 134TO BE STEERED WEST-NORTHWESTWARD UNTIL IT REACHES THE WESTERN 135PERIPHERY OF THE RIDGE ON DAY 3. A TURN TOWARD THE NORTHWEST AND 136NORTH-NORTHWEST IS THEN EXPECTED ON DAYS 4 AND 5. THE TRACK 137GUIDANCE ENVELOPE HAS SHIFTED TO THE WEST ON THIS CYCLE BUT IS 138STILL IN RELATIVELY GOOD AGREEMENT. THE NEW NHC FORECAST HAS 139THEREFORE BEEN NUDGED WESTWARD ON DAYS 4 AND 5. THIS TRACK ENDS UP 140VERY CLOSE TO THE GFS AND ECMWF SOLUTIONS...WHICH ARE NEARLY 141IDENTICAL ON DAY 5. 142 143FORECAST POSITIONS AND MAX WINDS 144 145INIT 23/0300Z 13.8N 39.5W 30 KT 35 MPH 146 12H 23/1200Z 14.5N 41.5W 35 KT 40 MPH 147 24H 24/0000Z 15.4N 44.1W 35 KT 40 MPH 148 36H 24/1200Z 16.4N 46.7W 35 KT 40 MPH 149 48H 25/0000Z 17.6N 49.5W 40 KT 45 MPH 150 72H 26/0000Z 21.0N 55.5W 40 KT 45 MPH 151 96H 27/0000Z 25.0N 62.0W 45 KT 50 MPH 152120H 28/0000Z 30.0N 65.5W 50 KT 60 MPH 153 154$$ 155FORECASTER BERG 156 157 158WTNT45 KNHC 230858 159TCDAT5 160 161TROPICAL DEPRESSION TEN DISCUSSION NUMBER 4 162NWS NATIONAL HURRICANE CENTER MIAMI FL AL102012 163500 AM AST THU AUG 23 2012 164 165DEEP CONVECTION WITH THE TROPICAL DEPRESSION CONTINUES TO BE 166SPORADIC THOUGH WITH QUITE COLD CLOUD TOPS. THE CENTER APPEARS TO 167BE NEAR THE SOUTH SIDE OF THE CONVECTION SUGGESTING THAT THE 168MODERATE SOUTHERLY VERTICAL SHEAR IS INHIBITING ITS DEVELOPMENT. 169AS A RESULT OF THE LACK OF IMPROVEMENT OF THE ORGANIZATION OF THE 170DEEP CONVECTION...THE DVORAK CLASSIFICATIONS FROM TAFB AND SAB 171REMAIN AT A 2.0...OR ABOUT 30 KT. IN CONTRAST...TWO RECENT AMSU 172SATELLITE PASSES SUGGEST THAT THE CYCLONE MAY BE A 35 TO 45 KT 173TROPICAL STORM. GIVEN THE UNIMPRESSIVE CONVECTIVE STRUCTURE...THE 174SYSTEM REMAINS AS A 30-KT TROPICAL DEPRESSION. 175 176A 0406Z AMSU IMAGE FROM THE NRL WEBSITE PROVIDES MODERATE CONFIDENCE 177IN THE INITIAL POSITION OF THE TROPICAL DEPRESSION. THE CURRENT 178MOTION OF THE SYSTEM CONTINUES TOWARD THE WEST-NORTHWEST...295 179DEGREES...AT 14 KT...AS THE CYCLONE IS BEING ADVECTED AROUND THE 180SOUTHERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE. THE SYSTEM 181SHOULD GRADUALLY TURN TOWARD THE NORTH-NORTHWEST BY DAY FIVE AS IT 182REACHES THE WESTERN SIDE OF THE RIDGE. THE GLOBAL AND REGIONAL 183TRACK GUIDANCE SHOWS RELATIVELY TIGHT CLUSTERING AND HAD LITTLE 184CHANGE FROM THE PREVIOUS MODEL CYCLE. THUS THE TRACK FORECAST IS 185NEARLY IDENTICAL TO BOTH THE LAST ADVISORY AND THE HFIP TV15 186CONSENSUS. 187 188THE INTENSITY PREDICTION IS MORE PROBLEMATIC THAN THE TRACK 189FORECAST. THE AFOREMENTIONED MODERATE VERTICAL SHEAR IS PRIMARILY 190BEING INDUCED BY AN UPPER LOW LOCATED ABOUT 600 NM NORTHWEST OF THE 191CYCLONE. THE TROPICAL DEPRESSION AND THE UPPER LOW SHOULD GET 192CLOSER TOGETHER OVER THE NEXT THREE DAYS...WHICH WOULD CONTINUE 193MODERATE SHEAR ACROSS THE CYCLONE. ON DAYS FOUR AND FIVE...THE 194VERTICAL SHEAR MAY INCREASE DUE TO THE OUTFLOW OF ISAAC. 195MOREOVER...THE THERMODYNAMICS ARE NOT CONDUCIVE FOR MUCH 196INTENSIFICATION AS SOME DRY STABLE AIR ASSOCIATED WITH A SAHARAN 197AIR LAYER...WORKING IN CONCERT WITH THE VERTICAL SHEAR...MAY BE 198REACHING THE INNER CORE OF THE CYCLONE DURING THE NEXT TWO TO THREE 199DAYS. THUS ONLY VERY GRADUAL INTENSIFICATION IS SHOWN THROUGHOUT 200THE FORECAST PERIOD IN BEST AGREEMENT WITH HWRF AND SHIPS MODELS. 201THE PREDICTED INTENSITIES ARE REDUCED SLIGHTLY FROM THE PREVIOUS 202ADVISORY. AN ALTERNATIVE SCENARIO DEPICTED BY THE ECMWF AND GFDL 203MODELS IS THAT THE CYCLONE COULD SUCCOMB TO THE HOSTILE ENVIRONMENT 204AND DISSIPATE BEFORE THE END OF THE FORECAST PERIOD. 205 206FORECAST POSITIONS AND MAX WINDS 207 208INIT 23/0900Z 14.5N 40.6W 30 KT 35 MPH 209 12H 23/1800Z 15.2N 42.5W 35 KT 40 MPH 210 24H 24/0600Z 16.2N 45.0W 35 KT 40 MPH 211 36H 24/1800Z 17.4N 47.7W 35 KT 40 MPH 212 48H 25/0600Z 18.8N 50.8W 35 KT 40 MPH 213 72H 26/0600Z 22.0N 57.0W 40 KT 45 MPH 214 96H 27/0600Z 27.0N 63.0W 45 KT 50 MPH 215120H 28/0600Z 31.0N 64.5W 45 KT 50 MPH 216 217$$ 218FORECASTER LANDSEA 219 220 221