1WTNT44 KNHC 140248 2TCDAT4 3 4Tropical Storm Humberto Discussion Number 6 5NWS National Hurricane Center Miami FL AL092019 61100 PM EDT Fri Sep 13 2019 7 8Deep convection has been gradually increasing this evening, and it 9is currently most organized in a curved band to the east of the 10estimated center. In addition, data from the NOAA Hurricane Hunters 11indicate that the depression has strengthened. The maximum 12flight-level wind at 700 mb was 41 kt and reliable SFMR values were 1335 kt. Based on that data, the initial intensity is increased to 35 14kt, making the cyclone Tropical Storm Humberto. The data from the 15aircraft indicate that the cyclone is titled to the northeast with 16height, likely due to southwesterly wind shear. 17 18Humberto has been moving erratically during the past 12 to 18 hours 19as the cyclone has been trying to organize, but my best guess at the 20initial motion is 320/5. During the next few days, a ridge to the 21north of the system over the eastern United States and the western 22Atlantic is expected to slide southeastward, with a weakness in the 23ridge developing due to a mid- to upper-level trough over the 24northeastern U.S. This change in the steering pattern should cause 25the depression to slow down and turn northward off the east coast of 26Florida in 36 to 48 hours. The models show the trough over the 27northeastern U.S. amplifying early next week, which should cause 28Humberto to turn northeastward and then eastward away from the U.S. 29The NHC track forecast has been nudged south and east of the 30previous one to be in better agreement with the latest consensus 31models. Since there is increasing confidence that the storm will 32remain well offshore of the coast of Florida, the Tropical Storm 33Watch for that area has been discontinued. 34 35The storm is still feeling some effects of southwesterly shear 36and drier air, which is causing its lopsided appearance in 37satellite images and strong tilt in the aircraft data. The 38atmospheric conditions are expected to gradually become more 39conducive for strengthening while Humberto moves over the warm 40Gulf Stream waters. These environmental parameters support 41intensification, and the cyclone is expected to become a hurricane 42in 2 to 3 days. The NHC intensity forecast is largely an update of 43the previous one and in line with the HCCA and IVCN guidance. 44 45Key Messages: 46 471. Humberto will likely bring tropical-storm-force winds and heavy 48rainfall to portions of the northwestern Bahamas on Saturday. 49Significant storm surge is not expected in the northwest Bahamas 50from this system. Residents there should follow any advice given by 51local officials. 52 532. Heavy rainfall and scattered flash flooding is possible this 54weekend in coastal sections of eastern Florida, Georgia, and South 55Carolina. The chance of heavy rainfall affecting coastal North 56Carolina early next week continues to diminish. 57 58 59FORECAST POSITIONS AND MAX WINDS 60 61INIT 14/0300Z 25.6N 75.2W 35 KT 40 MPH 62 12H 14/1200Z 26.5N 76.5W 35 KT 40 MPH 63 24H 15/0000Z 27.6N 77.6W 40 KT 45 MPH 64 36H 15/1200Z 28.8N 78.2W 50 KT 60 MPH 65 48H 16/0000Z 29.8N 78.1W 60 KT 70 MPH 66 72H 17/0000Z 31.0N 75.5W 70 KT 80 MPH 67 96H 18/0000Z 31.3N 72.0W 75 KT 85 MPH 68120H 19/0000Z 32.3N 67.2W 75 KT 85 MPH 69 70$$ 71Forecaster Cangialosi 72 73 74 75------------=_1568429307-121860-1445 76Content-Type: text/plain; charset="US-ASCII" 77Content-Disposition: inline 78Content-Transfer-Encoding: 7BIT 79 80= = = == = = 81WTNT44 KNHC 140300 CCA 82TCDAT4 83 84Tropical Storm Humberto Discussion Number 6...Corrected 85NWS National Hurricane Center Miami FL AL092019 861100 PM EDT Fri Sep 13 2019 87 88Corrected to change depression to storm in the second paragraph 89 90Deep convection has been gradually increasing this evening, and it 91is currently most organized in a curved band to the east of the 92estimated center. In addition, data from the NOAA Hurricane Hunters 93indicate that the depression has strengthened. The maximum 94flight-level wind at 700 mb was 41 kt and reliable SFMR values were 9535 kt. Based on that data, the initial intensity is increased to 35 96kt, making the cyclone Tropical Storm Humberto. The data from the 97aircraft indicate that the cyclone is titled to the northeast with 98height, likely due to southwesterly wind shear. 99 100Humberto has been moving erratically during the past 12 to 18 hours 101as the cyclone has been trying to organize, but my best guess at the 102initial motion is 320/5. During the next few days, a ridge to the 103north of the system over the eastern United States and the western 104Atlantic is expected to slide southeastward, with a weakness in the 105ridge developing due to a mid- to upper-level trough over the 106northeastern U.S. This change in the steering pattern should cause 107the storm to slow down and turn northward off the east coast of 108Florida in 36 to 48 hours. The models show the trough over the 109northeastern U.S. amplifying early next week, which should cause 110Humberto to turn northeastward and then eastward away from the U.S. 111The NHC track forecast has been nudged south and east of the 112previous one to be in better agreement with the latest consensus 113models. Since there is increasing confidence that the storm will 114remain well offshore of the coast of Florida, the Tropical Storm 115Watch for that area has been discontinued. 116 117The storm is still feeling some effects of southwesterly shear 118and drier air, which is causing its lopsided appearance in 119satellite images and strong tilt in the aircraft data. The 120atmospheric conditions are expected to gradually become more 121conducive for strengthening while Humberto moves over the warm 122Gulf Stream waters. These environmental parameters support 123intensification, and the cyclone is expected to become a hurricane 124in 2 to 3 days. The NHC intensity forecast is largely an update of 125the previous one and in line with the HCCA and IVCN guidance. 126 127Key Messages: 128 1291. Humberto will likely bring tropical-storm-force winds and heavy 130rainfall to portions of the northwestern Bahamas on Saturday. 131Significant storm surge is not expected in the northwest Bahamas 132from this system. Residents there should follow any advice given by 133local officials. 134 1352. Heavy rainfall and scattered flash flooding is possible this 136weekend in coastal sections of eastern Florida, Georgia, and South 137Carolina. The chance of heavy rainfall affecting coastal North 138Carolina early next week continues to diminish. 139 140 141FORECAST POSITIONS AND MAX WINDS 142 143INIT 14/0300Z 25.6N 75.2W 35 KT 40 MPH 144 12H 14/1200Z 26.5N 76.5W 35 KT 40 MPH 145 24H 15/0000Z 27.6N 77.6W 40 KT 45 MPH 146 36H 15/1200Z 28.8N 78.2W 50 KT 60 MPH 147 48H 16/0000Z 29.8N 78.1W 60 KT 70 MPH 148 72H 17/0000Z 31.0N 75.5W 70 KT 80 MPH 149 96H 18/0000Z 31.3N 72.0W 75 KT 85 MPH 150120H 19/0000Z 32.3N 67.2W 75 KT 85 MPH 151 152$$ 153Forecaster Cangialosi 154 155 156 157------------=_1568430094-121860-1448 158Content-Type: text/plain; charset="US-ASCII" 159Content-Disposition: inline 160Content-Transfer-Encoding: 7BIT 161 162= = = == = = 163WTNT44 KNHC 140842 164TCDAT4 165 166Tropical Storm Humberto Discussion Number 7 167NWS National Hurricane Center Miami FL AL092019 168500 AM EDT Sat Sep 14 2019 169 170Convection associated with Humberto has increased a little since 171the last advisory, as a new burst has occurred to the north of the 172center. Other convection continues in a large curved band in the 173eastern semicircle. Reports from an Air Force Reserve Hurricane 174Hunter aircraft near 0500 UTC indicated that the maximum sustained 175winds were near 35 kt, and that will be the initial intensity for 176this advisory. It should be noted that an upper-level trough is 177located just south of Humberto, and the storm may have some 178subtropical characteristics due to interaction with this trough. 179 180While the motion is still a bit erratic, Humberto now seems to be 181moving a little faster toward the northwest or 315/6 kt. During the 182next few days, a low- to mid-level ridge over the eastern United 183States and the western Atlantic is expected to slide southeastward, 184with a weakness in the ridge developing due to a mid- to upper-level 185trough over the northeastern U.S. This change in the steering 186pattern should cause the storm to slow down and turn northward off 187the east coast of Florida in 36 to 48 hours. Subsequently, the 188northeastern U.S. trough should dig southward, and this change 189should turn Humberto northeastward and then eastward away from the 190U.S. The track guidance has shifted a little more to the east 191during the first 72 h, and the new NHC track has been nudged 192eastward as well during this time. The new forecast track lies near 193the various consensus models. 194 195Southwesterly vertical shear and dry air entrainment caused by the 196upper-level trough to the south is forecast to diminish during the 197next 2-3 days while Humberto moves near or over the warm waters of 198the Gulf Stream. This should allow intensification, and Humberto 199is expected to become a hurricane in about 48 h. The intensity 200forecast becomes more uncertain between 72-120 h. Strong 201upper-level winds associated with the mid-latitude trough over the 202eastern United States should cause strong shear over Humberto. 203However, there is a chance that baroclinic forcing from the trough 204could compensate for the shear, and the GFS, ECMWF, UKMET, Canadian, 205and HWRF models all show the central pressure falling during this 206time. The intensity forecast will follow this guidance and show some 207additional strengthening through 96 h. Overall, the new intensity 208forecast is similar to, but slightly higher than, the previous 209forecast. 210 211 212Key Messages: 213 2141. Humberto will likely bring tropical-storm-force winds and heavy 215rainfall to portions of the northwestern Bahamas today. Significant 216storm surge is not expected in the northwestern Bahamas from this 217system. Residents there should follow any advice given by local 218officials. 219 2202. Since the forecast track has shifted farther to the east, the 221chance of heavy rainfall affecting the southeastern United States 222has diminished. 223 224 225FORECAST POSITIONS AND MAX WINDS 226 227INIT 14/0900Z 26.3N 76.0W 35 KT 40 MPH 228 12H 14/1800Z 26.9N 76.9W 40 KT 45 MPH 229 24H 15/0600Z 28.0N 77.7W 45 KT 50 MPH 230 36H 15/1800Z 29.0N 77.9W 55 KT 65 MPH 231 48H 16/0600Z 29.8N 77.4W 65 KT 75 MPH 232 72H 17/0600Z 30.8N 74.7W 75 KT 85 MPH 233 96H 18/0600Z 31.5N 71.0W 80 KT 90 MPH 234120H 19/0600Z 33.0N 66.0W 75 KT 85 MPH 235 236$$ 237Forecaster Beven 238 239 240 241------------=_1568450578-121860-1515 242Content-Type: text/plain; charset="US-ASCII" 243Content-Disposition: inline 244Content-Transfer-Encoding: 7BIT 245 246= = = == = = 247WTNT44 KNHC 141449 248TCDAT4 249 250Tropical Storm Humberto Discussion Number 8 251NWS National Hurricane Center Miami FL AL092019 2521100 AM EDT Sat Sep 14 2019 253 254The center of Humberto is better defined today, but due to shear, it 255is still located south of the main area of deep convection. 256Satellite images indicate that a cyclonically-curved convective band 257is also developing southeast of the center. Recent reports from an 258Air Force reconnaissance plane indicate that the winds have 259increased, and the maximum intensity has been adjusted upward to 45 260kt. These strong winds are confined to the north and east of the 261center of the cyclone. 262 263The current unfavorable shear over Humberto is forecast to weaken, 264and since the cyclone is expected to move over warm waters, the NHC 265forecast calls for strengthening. Humberto is anticipated to become 266a hurricane in about 36 hours over the western Atlantic well east of 267the Florida east coast and well away from the Bahamas. The intensity 268forecast is consistent with the solutions of the consensus model and 269the corrected consensus HCCA. In addition, all global models 270intensify Humberto and show an increase in the size of the storm. 271 272Satellite and reconnaissance fixes indicate that Humberto has barely 273moved during the past few hours. Humberto is being trapped by a 274ridge to the north, but this feature is forecast to weaken. The 275expected flow pattern should steer the cyclone very slowly toward 276the northwest and north during the next 24 to 36 hours. After 277that time, the cyclone will encounter the mid-latitude westerlies, 278and most likely, Humberto will sharply recurve northeastward away 279from the United States with no significant increase in forward 280speed. Only by the end of the forecast period, Humberto should begin 281to accelerate. The NHC forecast is very consistent with the track 282guidance which clearly depict the slow motion of the system and 283the sharp turn to the right in 2 or 3 days. 284 285Key Messages: 286 2871. Humberto will likely bring tropical-storm-force winds and heavy 288rainfall to portions of the northwestern Bahamas today. Significant 289storm surge is not expected in the northwestern Bahamas from this 290system. Residents there should follow any advice given by local 291officials. 292 293 294FORECAST POSITIONS AND MAX WINDS 295 296INIT 14/1500Z 26.6N 76.7W 45 KT 50 MPH 297 12H 15/0000Z 27.6N 77.6W 55 KT 65 MPH 298 24H 15/1200Z 28.7N 78.1W 60 KT 70 MPH 299 36H 16/0000Z 29.5N 78.0W 65 KT 75 MPH 300 48H 16/1200Z 30.0N 77.0W 70 KT 80 MPH 301 72H 17/1200Z 30.5N 74.5W 80 KT 90 MPH 302 96H 18/1200Z 31.5N 70.0W 85 KT 100 MPH 303120H 19/1200Z 34.5N 63.0W 90 KT 105 MPH 304 305$$ 306Forecaster Avila 307 308 309 310------------=_1568472571-121860-1599 311Content-Type: text/plain; charset="US-ASCII" 312Content-Disposition: inline 313Content-Transfer-Encoding: 7BIT 314 315= = = == = = 316WTNT44 KNHC 142036 317TCDAT4 318 319Tropical Storm Humberto Discussion Number 9 320NWS National Hurricane Center Miami FL AL092019 321500 PM EDT Sat Sep 14 2019 322 323An Air Force Hurricane Hunter plane extensively investigated 324Humberto during the past several hours. Data from the plane 325indicated that the circulation was much better defined than 326yesterday and the winds increased to 45 kt. Since the plane 327left, satellite images revealed that the cloud pattern has 328continued to become better organized, and the low-level center 329is now under the convection. However, the Dvorak numbers still 330support keeping the same intensity of 45 kt at this time. 331 332Now that the shear appears to be decreasing and Humberto will be 333moving over warm waters, the NHC forecast continues 334to call for strengthening. Humberto is anticipated to become 335a hurricane in about 36 hours over the western Atlantic well east 336of the Florida east coast, and well away from the Bahamas. The 337intensity forecast continues to be consistent with the solutions 338of the consensus model and the corrected consensus HCCA. In 339addition, all global models intensify Humberto and show an increase 340in the size of the storm. 341 342Satellite and reconnaissance fixes indicate that Humberto has 343begun to move very slowly toward the north-northwest or 330 degrees 344at 6 kt. The ridge over the western Atlantic that has been trapping 345Humberto is already weakening, and this should result in a slow 346motion toward the north-northwest and then north during the next day 347or so. After that time, the cyclone will encounter the mid-latitude 348westerlies, and Humberto, by then a hurricane, is forecast to 349sharply recurve northeastward away from the United States with no 350significant increase in forward speed. Only by the end of the 351forecast period, Humberto should begin to accelerate. The NHC 352forecast is very consistent with the track guidance which once again 353clearly depict the slow motion of the system, and then a sharp right 354turn in 2 or 3 days. 355 356 357FORECAST POSITIONS AND MAX WINDS 358 359INIT 14/2100Z 27.4N 77.3W 45 KT 50 MPH 360 12H 15/0600Z 28.2N 77.9W 55 KT 65 MPH 361 24H 15/1800Z 29.3N 78.3W 60 KT 70 MPH 362 36H 16/0600Z 29.9N 77.9W 65 KT 75 MPH 363 48H 16/1800Z 30.5N 76.7W 75 KT 85 MPH 364 72H 17/1800Z 31.2N 73.5W 85 KT 100 MPH 365 96H 18/1800Z 32.5N 67.5W 90 KT 105 MPH 366120H 19/1800Z 36.0N 61.0W 80 KT 90 MPH 367 368$$ 369Forecaster Avila 370 371 372 373------------=_1568493390-121860-1702 374Content-Type: text/plain; charset="US-ASCII" 375Content-Disposition: inline 376Content-Transfer-Encoding: 7BIT 377 378= = = == = = 379WTNT44 KNHC 150233 380TCDAT4 381 382Tropical Storm Humberto Discussion Number 10 383NWS National Hurricane Center Miami FL AL092019 3841100 PM EDT Sat Sep 14 2019 385 386Humberto is gradually strengthening. Both the NOAA and Air Force 387Hurricane Hunters have been investigating the storm this evening and 388they have found that the cyclone is a little stronger. Based on 389that data, the initial wind speed is nudged upward to 50 kt and the 390minimum pressure is around 1000 mb. Satellite images also show 391that the storm's structure is improving with an inner core trying to 392form and banding features becoming better defined to the north of 393the center. Doppler radar data from the NOAA P-3 aircraft indicate 394that the cyclone has become less titled in the vertical, suggesting 395that the shear has lessened over the system. However, there is 396still some signs of dry air being wrapped into the southern side of 397the circulation. 398 399Satellite and aircraft fixes indicate that the storm is moving 400north-northwestward at about 5 kt, steered by a mid-level ridge to 401its north-northeast over the western Atlantic. Humberto is expected 402to slow down and turn northward on Sunday well off the coast of 403east-central Florida as it moves into a developing weakness in the 404ridge. After that time, a turn to the northeast and then the 405east-northeast with a gradual increase in forward speed is predicted 406as Humberto moves along with the flow near the base of a large scale 407trough. The track models are in relatively good agreement, and only 408small changes were made to the previous forecast. 409 410The tropical storm is likely to continue strengthening during the 411next 3 to 4 days as it remains in relatively low wind shear 412conditions and over the warm Gulf Stream waters. Beyond that time, 413an increase in wind shear associated with an approaching shortwave 414trough will likely cause some weakening. The NHC intensity forecast 415is slightly higher than the previous one and shows Humberto becoming 416a hurricane in about 24 hours with additional strengthening 417thereafter. This forecast is in best agreement with the intensity 418consensus models HCCA, IVDR, and IVCN. 419 420The global models suggest that as Humberto gains latitude and 421intensifies, its wind field will gradually expand, and that 422is reflected in the NHC wind radii forecast. 423 424FORECAST POSITIONS AND MAX WINDS 425 426INIT 15/0300Z 27.6N 77.3W 50 KT 60 MPH 427 12H 15/1200Z 28.5N 77.8W 60 KT 70 MPH 428 24H 16/0000Z 29.3N 77.8W 65 KT 75 MPH 429 36H 16/1200Z 29.9N 77.1W 70 KT 80 MPH 430 48H 17/0000Z 30.4N 75.8W 75 KT 85 MPH 431 72H 18/0000Z 31.2N 72.0W 90 KT 105 MPH 432 96H 19/0000Z 33.0N 65.6W 95 KT 110 MPH 433120H 20/0000Z 36.9N 58.9W 75 KT 85 MPH 434 435$$ 436Forecaster Cangialosi 437 438 439 440------------=_1568514849-121860-1806 441Content-Type: text/plain; charset="US-ASCII" 442Content-Disposition: inline 443Content-Transfer-Encoding: 7BIT 444 445= = = == = = 446WTNT44 KNHC 150856 447TCDAT4 448 449Tropical Storm Humberto Discussion Number 11 450NWS National Hurricane Center Miami FL AL092019 451500 AM EDT Sun Sep 15 2019 452 453Since reconnaissance aircraft departed the storm after midnight, the 454overall cloud pattern of Humberto has not changed appreciably. Both 455the earlier aircraft data and a blend of the most recent subjective 456satellite intensity estimates from SAB and TAFB still support an 457initial intensity of 50 kt. While there is significant banding 458evident over the northern and eastern portions of the circulation, 459the cyclone has not be able to maintain convection over the center, 460likely due to some mid-level dry air that has wrapped around the 461southwestern and southern part of the system. As Humberto moves 462slowly northward today, it will be over warm water and generally 463within low vertical wind shear. This should allow for 464strengthening, and the NHC foreast continues to calls for Humberto 465to become a hurricane later today or tonight. Additional 466strengthening is likely after that time when the storm recurves and 467remains within favorable environmental conditions. Late in the 468period, Humberto is forecast to interact with an approaching 469mid-latitude trough, and increasing shear ahead of that system is 470likely to cause weakening. This interaction should also begin 471Humberto's transition to an extratropical cyclone. The updated NHC 472intensity forecast is essentially unchanged from the previous 473advisory and is in best agreement with the HFIP corrected consensus 474model. 475 476Humberto continues to be steered north-northwestward at about 6 kt 477by a mid-level ridge over the western Atlantic. The tropical storm 478should turn northward and slow down later today as a weakness 479develops in the ridge. On Monday, a broad trough over the the 480northeastern United States is expected to turn Humberto 481northeastward, and then east-northeastward away from the United 482States. The dynamical models remain in good agreement on the 483overall track forecast scenario but there are some differences in 484the forward speed of Humberto after the east-northeastward turn. 485The latest NHC track is similar to, but a little slower than, the 486previous advisory. The new track forecast is closest to the 487multi-model consensus to account for the forward speed differences 488among the guidance. 489 490Large swells from Humberto will affect portions of the northwestern 491Bahamas and southeastern United States coast during the next few 492days. These swells are expected to produce dangerous surf 493conditions and life-threatening rip currents. See products issued 494by your local weather office for additional information. 495 496 497FORECAST POSITIONS AND MAX WINDS 498 499INIT 15/0900Z 28.3N 77.7W 50 KT 60 MPH 500 12H 15/1800Z 29.0N 77.9W 60 KT 70 MPH 501 24H 16/0600Z 29.6N 77.6W 65 KT 75 MPH 502 36H 16/1800Z 30.1N 76.7W 70 KT 80 MPH 503 48H 17/0600Z 30.5N 75.3W 75 KT 85 MPH 504 72H 18/0600Z 31.3N 71.2W 90 KT 105 MPH 505 96H 19/0600Z 33.5N 64.5W 95 KT 110 MPH 506120H 20/0600Z 38.0N 58.0W 70 KT 80 MPH 507 508$$ 509Forecaster Brown 510 511 512 513------------=_1568537773-121860-1883 514Content-Type: text/plain; charset="US-ASCII" 515Content-Disposition: inline 516Content-Transfer-Encoding: 7BIT 517 518= = = == = = 519WTNT44 KNHC 151454 520TCDAT4 521 522Tropical Storm Humberto Discussion Number 12 523NWS National Hurricane Center Miami FL AL092019 5241100 AM EDT Sun Sep 15 2019 525 526Visible and passive microwave satellite imagery indicate that 527Humberto's inner-core region has improved markedly since early this 528morning, including the development of a small but ragged mid-level 529eye. In addition, significant dry air entrainment that has been 530plaguing the cyclone since its formation appears to have abated 531based on the recent development of deep convection in the dry slot 532located in the southern semicircle of Humberto's circulation. 533Anticyclonic outflow has also been increasing in all quadrants, 534along with a hint of cloud-filled eye in recent visible imagery. 535Buoy 41010 located just west of the center recently reported a 536pressure of 1001.8 mb and 41-kt winds at 4-meters elevation. The 537initial intensity has been increased to 55 kt based on a Dvorak 538intensity estimate of T3.5/55 kt from TAFB. AN Air Force Reserve 539reconnaissance aircraft will reconnoiter Humberto this afternoon, 540providing more detailed information on the cyclone's intensity. 541 542The initial motion estimate is 350/06 kt, based mainly on microwave 543satellite fix positions. NHC model guidance remains in excellent 544agreement on Humberto moving slowly northward through a break in the 545subtropical ridge today and tonight, then making a sharp turn toward 546the northeast on Monday when the cyclone passes north of the narrow 547east-west oriented ridge axis. On days 2-5, the tropical cyclone is 548forecast to gradually accelerate toward the northeast and 549east-northeast under the influence of increasing westerlies ahead of 550a deepening mid-latitude trough forecast to dig southeastward out of 551Canada and into the extreme northwestern Atlantic Ocean. The new 552official forecast track is very similar to the previous advisory 553track, and lies close to a blend of the tightly packed consensus 554track models. 555 556Humberto now appears to be well on its way to becoming a hurricane 557fairly soon based on the newly formed central dense overcast and 558mid-level eye feature. Although the large-scale shear is fairly 559large in the SHIPS intensity models, the shear directly over the 560center of Humberto is forecast to remain low for the next 48 hours 561or so, which should allow for steady strengthening. By 72 hours, the 562cyclone is forecast to be situated in the right-rear quadrant of a 563strong, anticyclonically curved jet maximum. The associated 564upper-level divergence is expected to induce strong pressure falls 565and strengthening despite the vertical shear increasing to more than 56630 kt. By 96 hours and beyond, slightly cooler waters, much drier 567air, and very hostile shear conditions of more than 40 kt should 568cause steady weakening. The new NHC intensity forecast follows the 569trend of the previous advisory, but now shows Humberto reaching peak 570intensity in 72 hours, coincident with the warmest water 571temperatures of about 29C and greatest jetstream dynamical forcing. 572 573Large swells from Humberto will affect portions of the northwestern 574Bahamas and southeastern United States coast during the next few 575days. These swells are expected to produce dangerous surf 576conditions and life-threatening rip currents. See products issued 577by your local weather office for additional information. 578 579FORECAST POSITIONS AND MAX WINDS 580 581INIT 15/1500Z 28.9N 77.9W 55 KT 65 MPH 582 12H 16/0000Z 29.5N 77.7W 65 KT 75 MPH 583 24H 16/1200Z 30.0N 77.1W 70 KT 80 MPH 584 36H 17/0000Z 30.3N 75.9W 80 KT 90 MPH 585 48H 17/1200Z 30.7N 74.4W 85 KT 100 MPH 586 72H 18/1200Z 31.6N 69.6W 95 KT 110 MPH 587 96H 19/1200Z 34.5N 62.8W 85 KT 100 MPH 588120H 20/1200Z 39.0N 57.0W 65 KT 75 MPH 589 590$$ 591Forecaster Stewart 592 593 594 595------------=_1568559254-121860-1989 596Content-Type: text/plain; charset="US-ASCII" 597Content-Disposition: inline 598Content-Transfer-Encoding: 7BIT 599 600= = = == = = 601WTNT44 KNHC 152051 602TCDAT4 603 604Tropical Storm Humberto Discussion Number 13 605NWS National Hurricane Center Miami FL AL092019 606500 PM EDT Sun Sep 15 2019 607 608Humberto's convective structure continues to improve in satellite 609imagery and reflectivity data from the Melbourne NOAA Doppler 610weather radar, including intermittent appearances of a closed eye. 611An Air Force Reserve reconnaissance aircraft investigating Humberto 612this afternoon found SFMR winds of 58-59 kt in the northeastern 613quadrant outside of the heaviest rain areas, and that the pressure 614had fallen 4 mb during the past 2 hours, now down to 989 mb. Based 615on these data, the intensity has been increased to 60 kt. 616 617The initial motion estimate is now 360/05 kt. There are no 618significant changes to the previous forecast track or reasoning. 619Humberto is likely located on or near an east-west oriented ridge 620axis, and a sharp turn toward the northeast is likely during the 621next 6-12 hours. The latest NHC model guidance remains highly 622convergent on the previous forecast track and continues to show the 623cyclone gradually being accelerated toward the northeast and 624east-northeast during the 24-120 hour period. The large deep-layer 625trough and associated cold front that will be digging southward out 626of eastern Canada and the northeastern United States is forecast by 627the ECMWF model to develop a cutoff low over the northwestern 628Atlantic that results in some binary interaction with Humberto on 629day 5. However, this is a new development and is considered to be an 630outlier scenario at this time. The new forecast track is similar to 631the previous advisory and lies close to the TVCN and HCCA consensus 632track models. 633 634Likewise, there is no significant change to previous intensity 635forecast. All of the available model guidance continues to support 636steady strengthening for the 3 days. In 48-72 hours, Humberto is 637forecast to be moving into the right-rear quadrant of a strong, 638anticyclonically curved 300-200 mb jet maximum. The associated 639strong baroclinic/dynamical forcing is expected to produce strong 640pressure falls and strengthening despite the hostile vertical wind 641shear conditions of at least 30 kt. On days 4 and 5, the combination 642of slightly cooler waters, drier and more stable air, and much 643stronger vertical shear of 40-50 kt should cause steady weakening 644despite the favorable jetstream dynamics. The previous NHC intensity 645forecast remains unchanged, and continues to show Humberto reaching 646its peak intensity in 72 hours, coincident with the warmest 647sea-surface temperatures and strongest jetstream dynamical forcing. 648 649Large swells from Humberto will affect portions of the northwestern 650Bahamas and southeastern United States coast during the next few 651days. These swells are expected to produce dangerous surf 652conditions and life-threatening rip currents. See products issued 653by your local weather office for additional information. 654 655FORECAST POSITIONS AND MAX WINDS 656 657INIT 15/2100Z 29.3N 78.0W 60 KT 70 MPH 658 12H 16/0600Z 29.8N 77.6W 65 KT 75 MPH 659 24H 16/1800Z 30.1N 76.7W 70 KT 80 MPH 660 36H 17/0600Z 30.4N 75.4W 80 KT 90 MPH 661 48H 17/1800Z 30.7N 73.6W 85 KT 100 MPH 662 72H 18/1800Z 31.7N 68.9W 95 KT 110 MPH 663 96H 19/1800Z 35.0N 62.0W 85 KT 100 MPH 664120H 20/1800Z 39.6N 56.1W 60 KT 70 MPH 665 666$$ 667Forecaster Stewart 668 669 670 671------------=_1568580676-121860-2087 672Content-Type: text/plain; charset="US-ASCII" 673Content-Disposition: inline 674Content-Transfer-Encoding: 7BIT 675 676= = = == = = 677WTNT44 KNHC 160237 678TCDAT4 679 680Hurricane Humberto Discussion Number 14 681NWS National Hurricane Center Miami FL AL092019 6821100 PM EDT Sun Sep 15 2019 683 684700 mb flight-level wind data from a NOAA P-3 Hurricane Hunter 685aircraft investigating Humberto indicate that the system's intensity 686is now 65 kt. This is also supported by Dvorak classifications 687from TAFB and SAB, and it makes the cyclone the third hurricane of 688the 2019 Atlantic season. Humberto's cloud pattern has continued to 689gradually become better organized, with increasing coverage and 690intensity of deep convection, and pronounced upper-level outflow 691over the eastern semicircle of the circulation. The hurricane is 692expected to traverse warm Gulf Stream waters for the next several 693days, but the dynamical models forecast a significant increase in 694southwesterly vertical shear through 72 hours. In spite of the 695latter unfavorable factor, the numerical guidance generally shows 696intensification. This is likely at least partially due to some 697baroclinic forcing caused by a strong mid-latitude trough to the 698north and northeast of Humberto. The official forecast is a blend 699of the latest simple and corrected consensus models and is very 700similar to the previous one. 701 702Humberto continues to move very slowly and the latest aircraft and 703satellite center fixes indicate that the motion is now 704northeastward or 040/3 kt. The hurricane has just rounded the 705western periphery of a subtropical anticyclone and steering 706currents are likely to remain weak for the next couple of days. An 707east-northeastward track with a very gradual increase in forward 708speed is expected for much of the period while Humberto moves 709between the subtropical high and stronger westerlies associated with 710the trough to the north. The new NHC track forecast is a little 711slower than the previous one in 4-5 days, but not as slow as the 712latest ECMWF and GFS global model runs. 713 714Large swells from Humberto will affect portions of the northwestern 715Bahamas and southeastern United States coast during the next few 716days. These swells are expected to produce dangerous surf 717conditions and life-threatening rip currents. See products issued 718by your local weather office for additional information. 719 720 721FORECAST POSITIONS AND MAX WINDS 722 723INIT 16/0300Z 29.4N 77.6W 65 KT 75 MPH 724 12H 16/1200Z 29.8N 77.1W 70 KT 80 MPH 725 24H 17/0000Z 30.1N 76.0W 75 KT 85 MPH 726 36H 17/1200Z 30.5N 74.7W 80 KT 90 MPH 727 48H 18/0000Z 30.8N 73.0W 85 KT 100 MPH 728 72H 19/0000Z 31.8N 68.3W 95 KT 110 MPH 729 96H 20/0000Z 35.0N 63.3W 80 KT 90 MPH 730120H 21/0000Z 39.0N 60.0W 60 KT 70 MPH 731 732$$ 733Forecaster Pasch 734 735 736 737------------=_1568601470-121860-2148 738Content-Type: text/plain; charset="US-ASCII" 739Content-Disposition: inline 740Content-Transfer-Encoding: 7BIT 741 742= = = == = = 743WTNT44 KNHC 160847 744TCDAT4 745 746Hurricane Humberto Discussion Number 15 747NWS National Hurricane Center Miami FL AL092019 748500 AM EDT Mon Sep 16 2019 749 750The satellite presentation of the hurricane has continued to 751improve overnight, with the center embedded within a fairly 752symmetric area of cold cloud tops. Although no eye is evident in 753conventional satellite imagery, a ragged eye could be seen in 754long-range NWS Doppler radar data from Melbourne, Florida early 755in the night. Satellite intensity estimates from TAFB, SAB, and 756UW/CIMSS all support an intensity of 75 kt, and that is used as the 757initial wind speed for this advisory. An Air Force Reserve 758Hurricane Hunter aircraft is scheduled to investigate Humberto this 759morning, and should provide a better assessment of the storm's 760strength. 761 762Humberto is likely to continue intensifying during the next day or 763so while it moves over the warm waters of the Gulf stream and the 764shear is not expected to be prohibitive. The updated NHC forecast 765depicts a faster rate of strengthening over the first 36 hours 766than before, and is at the upper end of the guidance through that 767time. By 48 hours, increasing westerly shear should slow the 768intensification process, but baroclinic forcing caused by a 769mid-latitude trough is likely to help the cyclone remain strong 770until it begins its extratropical transition later in the period. 771 772Humberto is moving northeastward or 050/3 kt. The hurricane is 773forecast to move slowly east-northeastward during the next 24 774hours, around the northwestern portion of a subtropical ridge. 775After that time, Humberto should continue on an east-northeastward 776heading, but at a slightly faster forward speed as a broad trough 777becomes established over the western Atlantic. Later in the period, 778a strong shortwave trough is forecast to dig southward which should 779cause Humberto to lift northeastward. The track guidance is in good 780agreement through 72 hours, and the confidence in that portion of 781the forecast is quite high. After that time, the forecast 782confidence decreases quite a bit as the model spread becomes 783unusually large. This is the due to differs in how Humberto 784interacts with the aforementioned trough. The GFS and HWRF shows 785Humberto getting caught by the trough as it cuts-off over the 786western Atlantic, while the ECMWF and UKMET show a more progressive 787solution, and take Humberto northeastward over the north Atlantic 788ahead of the trough. Given the model spread of more than 1000 n mi 789at day 5, the NHC track foreast remains close to the multi-model 790consensus, but confidence in the 4- and 5-day forecast is rather 791low. 792 793Large swells from Humberto will affect portions of the northwestern 794Bahamas and southeastern United States coast during the next few 795days. These swells are expected to produce dangerous surf 796conditions and life-threatening rip currents. See products issued 797by your local weather office for additional information. 798 799 800FORECAST POSITIONS AND MAX WINDS 801 802INIT 16/0900Z 29.7N 77.3W 75 KT 85 MPH 803 12H 16/1800Z 30.0N 76.6W 85 KT 100 MPH 804 24H 17/0600Z 30.3N 75.4W 90 KT 105 MPH 805 36H 17/1800Z 30.6N 73.9W 95 KT 110 MPH 806 48H 18/0600Z 31.0N 72.0W 95 KT 110 MPH 807 72H 19/0600Z 33.0N 66.5W 95 KT 110 MPH 808 96H 20/0600Z 37.0N 62.0W 75 KT 85 MPH 809120H 21/0600Z 40.0N 58.5W 55 KT 65 MPH...POST-TROP/EXTRATROP 810 811$$ 812Forecaster Brown 813 814 815 816------------=_1568623643-121860-2217 817Content-Type: text/plain; charset="US-ASCII" 818Content-Disposition: inline 819Content-Transfer-Encoding: 7BIT 820 821= = = == = = 822WTNT44 KNHC 161450 823TCDAT4 824 825Hurricane Humberto Discussion Number 16 826NWS National Hurricane Center Miami FL AL092019 8271100 AM EDT Mon Sep 16 2019 828 829An Air Force Reserve reconnaissance aircraft investigating Humberto 830this morning found peak 850-mb flight-level winds of 88 kt in the 831southeastern and northeastern quadrants, along with SFMR surface 832winds of 72-73 kt in the northeastern quadrant and a minimum 833pressure of 978 mb. These data support an intensity of 75 kt. 834 835The initial motion estimate is east-northeastward or 070/06 kt. 836Humberto is now solidly located north of the Bermuda-Azores ridge 837axis, and a continued east-northeastward motion is expected for the 83848 hours or so. Thereafter, a large deep-layer trough is forecast to 839dig southward out of Atlantic Canada and the Canadian Maritimes to 840the west of Humberto, forcing the hurricane to gradually lift out 841to the northeast. The exact timing that the trough begins to affect 842Humberto's motion will be critical in determining how close the 843hurricane will come to Bermuda. The latest model guidance is in 844better agreement and more tightly packed than previous runs, 845suggesting that the poleward turn will occur at least 100 n mi west 846of the island. By days 4 and 5, however, the model guidance becomes 847strongly divergent with a large spread of about 1000 n mi on day 5, 848resulting in lower-than-normal confidence in the track forecast on 849those days. The new NHC track foreast was nudged only slightly 850southward through 48 hours, and lies close to a blend of the 851consensus models TVCN, NOAA-HCCA, and FSSE. 852 853Humberto has been strengthening at a rate of 20 kt per 24 hours 854since this time yesterday, and that trend is expected to continue 855for the next day or so given the warm water beneath the hurricane 856and a continued favorable upper-level outflow pattern. The hurricane 857is expected to peak as a major hurricane in 36-48 hours when the 858cyclone will be located over SSTs of about 29 deg C and moving into 859the right-rear quadrant of a strong upper-level jet maximum. 860Thereafter, strong southwesterly vertical wind shear is expected to 861gradually diminish convection around the center despite the 862impressive baroclinic/dynamically driven pressure falls, which will 863mainly act to spread out the surface wind field rather than 864intensify the cyclone. Humberto is forecast to interact with an 865approaching cold front on day 5, resulting in extratropical 866transition over the colder Atlantic waters north of the Gulf Stream. 867The official intensity forecast is just an update of the previous 868advisory and now shows Humberto reaching major hurricane status, 869similar to the HCCA, FSSE, and HWRF models. Since Humberto's wind 870field is expected to expand significantly by day 2, a Tropical 871Storm Watch for Bermuda will likely be required on the 500 pm EDT 872advisory. 873 874Large swells from Humberto will affect portions of the northwestern 875Bahamas and southeastern United States coast during the next few 876days. These swells are expected to produce dangerous surf 877conditions and life-threatening rip currents. See products issued 878by your local weather office for additional information. 879 880FORECAST POSITIONS AND MAX WINDS 881 882INIT 16/1500Z 29.9N 76.5W 75 KT 85 MPH 883 12H 17/0000Z 30.1N 75.6W 85 KT 100 MPH 884 24H 17/1200Z 30.4N 74.4W 95 KT 110 MPH 885 36H 18/0000Z 30.7N 72.7W 100 KT 115 MPH 886 48H 18/1200Z 31.3N 70.5W 95 KT 110 MPH 887 72H 19/1200Z 33.7N 65.0W 85 KT 100 MPH 888 96H 20/1200Z 37.9N 60.9W 70 KT 80 MPH 889120H 21/1200Z 40.8N 56.8W 60 KT 70 MPH...POST-TROP/EXTRATROP 890 891$$ 892Forecaster Stewart 893 894 895 896------------=_1568645668-121860-2280 897Content-Type: text/plain; charset="US-ASCII" 898Content-Disposition: inline 899Content-Transfer-Encoding: 7BIT 900 901= = = == = = 902WTNT44 KNHC 162051 903TCDAT4 904 905Hurricane Humberto Discussion Number 17 906NWS National Hurricane Center Miami FL AL092019 907500 PM EDT Mon Sep 16 2019 908 909A NOAA Hurricane Hunter aircraft investigating Humberto this 910afternoon found peak 850-mb flight-level winds of 78 kt in the 911western quadrant, along with SFMR surface winds of 71-72 kt, which 912is an increase in the winds in this part of storm since the earlier 913Air Force Reserve reconnaissance flight. The NOAA aircraft also 914measured a central pressure of 972 mb, down 4 mb from the previous 915flight. A combination of subjective and objective satellite 916intensity estimates of 90 kt and the aircraft data support an 917initial intensity of 80 kt. 918 919The initial motion estimate remains east-northeastward or 070/06 kt. 920Humberto made a wobble to the north during the past few hours, but 921has now wobbled toward the east, which is an indication that the 922hurricane's inner core is continuing to consolidate and contract. 923That being said, the latest model guidance is in even better 924agreement with and more convergent about the previous forecast 925track. Thus no significant changed were required through 72 hours. 926Thereafter, the models are also now in better agreement that 927Humberto will not slow down as much as previously expected, and the 928hurricane is forecast to gradually lift out and accelerate to the 929northeast on days 4 and 5 when Humberto is well to the northeast of 930Bermuda. No significant track changes were made to the previous 931advisory track through 48 hours, with the track having been nudged 932southward slightly on days 3-5 in agreement with the consensus 933models TVCN, NOAA-HCCA, and FSSE. 934 935Humberto has continued to strengthen at a rate of 20 kt per 24 936hours, and I see no physical reasons why this trend should not 937continue for another 24-36 hours. By 48 hours and beyond, the 938hurricane will be entering the right-rear quadrant of a strong 939upper-level jet maximum that could briefly impart some additional 940baroclinic forcing on the cyclone, helping it to maintain its 941intensity or at least slow down the weakening process. By day 3 and 942beyond, however, the wind shear becomes prohibitively hostile at 943more than 50 kt, which should cause the central deep convection to 944erode, resulting in significant weakening. On day 5, extratropical 945transition over the colder north Atlantic waters is forecast to 946begin as Humberto interacts and possibly merges with a strong cold 947front. 948 949Large swells from Humberto will affect Bermuda by late Tuesday, and 950affect portions of the northwestern Bahamas and southeastern United 951States coast during the next couple of days. These swells are 952expected to produce dangerous surf conditions and life-threatening 953rip currents. See products issued by your local weather office and 954the Bermuda Weather Service for additional information. 955 956FORECAST POSITIONS AND MAX WINDS 957 958INIT 16/2100Z 30.2N 75.9W 80 KT 90 MPH 959 12H 17/0600Z 30.4N 74.9W 90 KT 105 MPH 960 24H 17/1800Z 30.8N 73.3W 95 KT 110 MPH 961 36H 18/0600Z 31.2N 71.3W 100 KT 115 MPH 962 48H 18/1800Z 32.0N 68.7W 95 KT 110 MPH 963 72H 19/1800Z 36.0N 61.3W 85 KT 100 MPH 964 96H 20/1800Z 40.1N 59.0W 70 KT 80 MPH 965120H 21/1800Z 41.7N 54.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 966 967$$ 968Forecaster Stewart 969 970 971 972------------=_1568667154-121860-2399 973Content-Type: text/plain; charset="US-ASCII" 974Content-Disposition: inline 975Content-Transfer-Encoding: 7BIT 976 977= = = == = = 978WTNT44 KNHC 170232 979TCDAT4 980 981Hurricane Humberto Discussion Number 18 982NWS National Hurricane Center Miami FL AL092019 9831100 PM EDT Mon Sep 16 2019 984 985Humberto continues to have an impressive overall appearance on 986satellite imagery, although the eye is a bit ragged looking. 987Earlier radar images from the NOAA P-3 aircraft showed that the 988eyewall was somewhat fragmented. A last-minute observation of 989700-mb flight-level winds of 86 kt from the Air Force Hurricane 990Hunters, outbound to the west of the eye, is roughly consistent with 991a current intensity estimate of 80 kt. Humberto should continue to 992traverse warm waters for the next couple of days, and much of the 993numerical guidance shows intensification in the short term. 994Therefore the official forecast, like the previous one, continues to 995call for the system to become a major hurricane within the next 996day or so. This is similar to the intensity model consensus. By 48 997hours, the shear should become very strong and a weakening trend 998will likely be underway. By day 5, if not sooner, the ECMWF global 999model shows the system embedded within a frontal zone so Humberto 1000is forecast to be extratropical at that time. 1001 1002The eye has been wobbling over the past few hours, but a smoothed 1003estimate of the motion is just north of east or 075/7 kt. Humberto 1004should continue to move along the northern side of a subtropical 1005ridge with a gradual increase in forward speed for the next couple 1006of days. After that, the hurricane should turn northeastward and 1007north-northeastward with some additional acceleration in response 1008to a strong mid-tropospheric trough near Atlantic Canada. Around 1009the end of the forecast period, the global models differ 1010significantly as to how far north into the Atlantic Humberto will 1011move. The official forecast leans toward the ECMWF and corrected 1012consensus, HCCA, guidance. 1013 1014It is still too early to give a good estimate as to how close the 1015core of the hurricane will come to Bermuda. Interests should not 1016focus on the exact forecast track; only a slight deviation to the 1017right could bring the center near or over the island. 1018 1019Large swells from Humberto will affect Bermuda by late Tuesday, and 1020affect portions of the northwestern Bahamas and southeastern United 1021States coast during the next couple of days. These swells are 1022expected to produce dangerous surf conditions and life-threatening 1023rip currents. See products issued by your local weather office and 1024the Bermuda Weather Service for additional information. 1025 1026 1027FORECAST POSITIONS AND MAX WINDS 1028 1029INIT 17/0300Z 30.3N 75.1W 80 KT 90 MPH 1030 12H 17/1200Z 30.7N 74.0W 90 KT 105 MPH 1031 24H 18/0000Z 31.1N 72.2W 95 KT 110 MPH 1032 36H 18/1200Z 31.6N 70.0W 100 KT 115 MPH 1033 48H 19/0000Z 32.8N 66.6W 90 KT 105 MPH 1034 72H 20/0000Z 37.1N 60.7W 80 KT 90 MPH 1035 96H 21/0000Z 40.5N 58.0W 65 KT 75 MPH 1036120H 22/0000Z 43.0N 50.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 1037 1038$$ 1039Forecaster Pasch 1040 1041 1042 1043------------=_1568687593-121860-2485 1044Content-Type: text/plain; charset="US-ASCII" 1045Content-Disposition: inline 1046Content-Transfer-Encoding: 7BIT 1047 1048= = = == = = 1049WTNT44 KNHC 170845 1050TCDAT4 1051 1052Hurricane Humberto Discussion Number 19 1053NWS National Hurricane Center Miami FL AL092019 1054500 AM EDT Tue Sep 17 2019 1055 1056The cloud pattern continues to be rather impressive, but the eye 1057is ragged looking and less defined than a few hours ago. Dvorak 1058estimates from TAFB and SAB have not changed significantly and 1059support an initial intensity of 80 kt. Another reconnaissance plane 1060will check the hurricane's structure in the morning. 1061 1062Humberto is expected to continue to moving over warm waters for 1063the next few days, and intensity guidance as well as global models 1064strengthen the hurricane a little more. On this basis, the NHC 1065forecast calls for the system to become a major hurricane in about 106624 to 36 hours. After that time, upper-level winds are expected to 1067be hostile, resulting in weakening. By day 5, if not sooner, the 1068cyclone should become embedded within a frontal zone and begin to 1069acquire extratropical characteristics at that time. 1070 1071Satellite fixes indicate that the initial motion continues toward 1072the east-northeast or 075 degrees at 7 kt. Humberto is well embedded 1073within the mid-latitude westerlies, and this general motion with 1074a turn to the northeast and an increase in forward speed is forecast 1075for the next 5 days. Track models are in good agreement with this 1076solution, and the NHC forecast remains in the middle of the guidance 1077envelope. It is also very similar to the previous official 1078forecast. 1079 1080It is still too early to give a good estimate as to how close the 1081core of the hurricane will come to Bermuda. Interests should not 1082focus on the exact forecast track; only a slight deviation to the 1083right could bring the center near or over the island. 1084 1085Large swells from Humberto will affect Bermuda by Wednesday and 1086will be affecting portions of the northwestern Bahamas and 1087southeastern United States coast during the next couple of days. 1088These swells are expected to produce dangerous surf conditions and 1089life-threatening rip currents. See products issued by your local 1090weather office and the Bermuda Weather Service for additional 1091information. 1092 1093 1094FORECAST POSITIONS AND MAX WINDS 1095 1096INIT 17/0900Z 30.6N 74.3W 80 KT 90 MPH 1097 12H 17/1800Z 31.0N 73.0W 90 KT 105 MPH 1098 24H 18/0600Z 31.6N 70.7W 95 KT 110 MPH 1099 36H 18/1800Z 32.5N 68.0W 100 KT 115 MPH 1100 48H 19/0600Z 34.0N 64.5W 90 KT 105 MPH 1101 72H 20/0600Z 38.0N 60.0W 70 KT 80 MPH 1102 96H 21/0600Z 42.0N 55.0W 65 KT 75 MPH 1103120H 22/0600Z 44.0N 45.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 1104 1105$$ 1106Forecaster Avila 1107 1108 1109 1110------------=_1568709938-121860-2568 1111Content-Type: text/plain; charset="US-ASCII" 1112Content-Disposition: inline 1113Content-Transfer-Encoding: 7BIT 1114 1115= = = == = = 1116WTNT44 KNHC 171458 1117TCDAT4 1118 1119Hurricane Humberto Discussion Number 20 1120NWS National Hurricane Center Miami FL AL092019 11211100 AM EDT Tue Sep 17 2019 1122 1123An Air Force Reserve reconnaissance aircraft that investigated 1124Humberto earlier this morning found 700-mb flight-level winds of 96 1125kt and 82-kt surface winds on a dropsonde in the southwestern 1126quadrant, and 81-kt SFMR surface winds in the northwestern quadrant. 1127More importantly, the wind data indicate that Humberto's wind field 1128has expanded significantly and is becoming asymmetric with the 1129largest wind radii now located in the southern semicircle. The 1130aircraft also measured a central pressure of 961 mb, down 18 mb 1131since this time yesterday. The central pressure typically 1132corresponds to an intensity of around 100 kt, but the expansion of 1133the wind field has resulted in little increase in the eyewall wind 1134field for now. Based on these data, the initial intensity has been 1135increased to 85 kt. 1136 1137Humberto has maintained an east-northeastward motion of 075/07 kt. 1138The hurricane is forecast to remain embedded within the mid-latitude 1139westerlies though the forecast period. A deep-layer trough is 1140forecast to dig southward to the west of Humberto in the 24-48 hour 1141period, causing the hurricane to gradually gain latitude and pass 1142just to the northwest of Bermuda in around 36 hours. The models are 1143in excellent agreement on this developing track scenario and are 1144tightly clustered around the previous advisory track. However, the 1145recent expansion of the wind field and the expected additional 1146increase in the wind on the southeast side of Humberto's circulation 1147will result in the island being in near-hurricane-force conditions. 1148By 72 hours and beyond, Humberto will accelerate northeastward 1149over the cold waters of the north Atlantic and interact with a 1150strong frontal system, resulting in the transition into a large 1151extratropical low. The official track forecast is similar to the 1152previous advisory track through 48 hours, and then is a little 1153faster in the 72-120 hour period, close to a blend of the various 1154consensus models. 1155 1156Due to the expansion of Humberto's wind field and large 35-40-n mi 1157wide eye, only modest strengthening is expected during the next 36 1158hours or so. Although not explicitly shown, Humberto could still 1159become a major hurricane between 24-36 hours when the cyclone will 1160be located over the warmest water of about 29C. Thereafter, 1161gradual wakening is forecast due to cooler waters and strong 1162southwesterly vertical wind shear in excess of 40 kt. However, the 1163typical rate of weakening due to such hostile shear conditions will 1164be tempered owing to the increasing baroclinic forcing in the 1165right-rear entrance region of a polar jet maximum. The new intensity 1166forecast is nearly identical to the previous advisory, and follows a 1167blend of the consensus models HCCA and FSSE. 1168 1169Key Messages: 1170 11711. Tropical-storm-force winds are expected to reach Bermuda by 1172Wednesday afternoon, with hurricane conditions possible Wednesday 1173night and Thursday morning. Residents there should follow advice 1174given by local officials. 1175 11762. Large swells will increase along the coast of Bermuda by 1177Wednesday. Dangerous breaking waves, especially along south-facing 1178beaches, could cause coastal flooding Wednesday night and Thursday. 1179 11803. Swells will continue to affect the northwestern Bahamas and the 1181southeastern coast of the United States from east-central Florida to 1182North Carolina during the next couple of days, creating life- 1183threatening surf and rip current conditions. 1184 1185FORECAST POSITIONS AND MAX WINDS 1186 1187INIT 17/1500Z 30.7N 73.5W 85 KT 100 MPH 1188 12H 18/0000Z 31.1N 72.0W 90 KT 105 MPH 1189 24H 18/1200Z 31.8N 69.4W 95 KT 110 MPH 1190 36H 19/0000Z 33.1N 66.1W 95 KT 110 MPH 1191 48H 19/1200Z 35.3N 62.6W 90 KT 105 MPH 1192 72H 20/1200Z 39.6N 58.4W 70 KT 80 MPH 1193 96H 21/1200Z 43.0N 52.2W 60 KT 70 MPH...POST-TROP/EXTRATROP 1194120H 22/1200Z 44.5N 40.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 1195 1196$$ 1197Forecaster Stewart 1198 1199 1200 1201------------=_1568732323-121860-2658 1202Content-Type: text/plain; charset="US-ASCII" 1203Content-Disposition: inline 1204Content-Transfer-Encoding: 7BIT 1205 1206= = = == = = 1207WTNT44 KNHC 172046 1208TCDAT4 1209 1210Hurricane Humberto Discussion Number 21 1211NWS National Hurricane Center Miami FL AL092019 1212500 PM EDT Tue Sep 17 2019 1213 1214Humberto's satellite appearance has improved somewhat since the 1215previous advisory, with the eye clearing out and becoming more 1216distinct. This has resulted in satellite subjective intensity 1217estimates increasing to T5.5/102 kt from TAFB and SAB, with 1218objective ADT estimates from UW-CIMSS increasing to T5.9/112 kt. 1219However, during the past 36 h or so, the satellite estimates have 1220been running higher than the actual surface winds by about 10-15 1221percent. A 1425Z ASCAT-C overpass indicated surface winds of 72 kt 1222in the southeastern eyewall, which is significant given that the 1223scatterometer is well undersampling the actual peak winds due to the 122425-km footprint of the instrument. The intensity has been increased 1225to 90 kt based on the clearing and warming of the eye and allowing 1226for some overestimation by the satellite agencies. The scatterometer 1227wind data also showed that Humberto's wind field has expanded more 1228since the earlier recon wind data, thus some additional adjustments 1229were made to all of the wind radii in this advisory. 1230 1231Humberto continues to move east-northeastward or 075/10 kt. The 1232large hurricane remains on track, and the latest NHC model guidance 1233remains tightly packed around the previous advisory track. Thus, no 1234significant changes were made to the previous forecast track through 123548 hours. By 72 hours and beyond, however, the models are now in 1236better agreement on Humberto accelerating and moving faster toward 1237the northeast through 96 hours as an extratropical cyclone, followed 1238by a turn toward the east-northeast on day 5. The official forecast 1239track is based on a blend of the consensus models TVCN, HCCA, and 1240FSSE, and shows the center of Humberto passing just to the northwest 1241and north of Bermuda between 24-36 hours or late Wednesday night. 1242 1243The latest SHIPS intensity guidance shows near 30 kt of deep-layer 1244vertical shear allegedly affecting Humberto, which obviously is a 1245significant overestimate based on the presence of a well-defined eye 1246and smooth CDO feature in visible satellite imagery. Given the 1247likely overestimation of the shear values, Humberto is expected to 1248strengthen to major hurricane status in the next 24 h. Thereafter, 1249Humberto is forecast to steadily weaken due to cold upwelling as the 1250hurricane moves over cooler waters, and into an environment 1251consisting of very strong shear exceeding 40-50 kt and more stable, 1252drier air. However, the usual rate of weakening due to the strong 1253shear conditions is expected to be tempered by the increasing 1254baroclinic forcing in the right-rear entrance region of a strong 1255jetstream wind maximum. The NHC intensity closely follows a blend of 1256the intensity consensus models IVCN, HCCA, and FSSE. 1257 1258Key Messages: 1259 12601. Hurricane conditions are expected in Bermuda Wednesday night and 1261Thursday morning, with tropical-storm-force winds expected by 1262Wednesday afternoon. Residents there should follow advice given by 1263local officials. 1264 12652. Storm surge and dangerous breaking waves could cause coastal 1266flooding Wednesday night and Thursday along the southern coast of 1267Bermuda. 1268 12693. Swells will continue to affect the northwestern Bahamas and the 1270southeastern coast of the United States from east-central Florida to 1271North Carolina during the next couple of days, creating life- 1272threatening surf and rip current conditions. 1273 1274FORECAST POSITIONS AND MAX WINDS 1275 1276INIT 17/2100Z 31.0N 72.3W 90 KT 105 MPH 1277 12H 18/0600Z 31.5N 70.5W 95 KT 110 MPH 1278 24H 18/1800Z 32.6N 67.6W 100 KT 115 MPH 1279 36H 19/0600Z 34.6N 63.9W 95 KT 110 MPH 1280 48H 19/1800Z 37.4N 61.0W 85 KT 100 MPH 1281 72H 20/1800Z 41.5N 57.2W 65 KT 75 MPH 1282 96H 21/1800Z 43.5N 48.5W 55 KT 65 MPH...POST-TROP/EXTRATROP 1283120H 22/1800Z 46.0N 34.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 1284 1285$$ 1286Forecaster Stewart 1287 1288 1289 1290------------=_1568753205-121860-2799 1291Content-Type: text/plain; charset="US-ASCII" 1292Content-Disposition: inline 1293Content-Transfer-Encoding: 7BIT 1294 1295= = = == = = 1296WTNT44 KNHC 180256 1297TCDAT4 1298 1299Hurricane Humberto Discussion Number 22 1300NWS National Hurricane Center Miami FL AL092019 13011100 PM EDT Tue Sep 17 2019 1302 1303Humberto has an impressive presentation on satellite images, with a 1304large 30-40 n mi diameter eye surrounded by very cold cloud tops. 1305An Air Force Reserve Unit Hurricane Hunter aircraft investigating 1306the hurricane found SFMR-observed surface winds of 98 kt and peak 1307700-mb flight-level winds of 111 kt. Based on these observations, 1308the current intensity was set at 100 kt, which made the system a 1309major hurricane. Some fluctuations in strength due to a potential 1310eyewall replacement are possible during the next 24 hours or so, but 1311strong southwesterly shear should result in a weakening trend to 1312commence on Thursday. In 72 hours, the global models show the 1313system merging with a frontal zone so the NHC forecast calls for 1314extratropical transition by that time. The official intensity 1315forecast follows the model consensus. 1316 1317Center fixes from the Hurricane Hunters indicate that the motion 1318continues to be east-northeastward or 075/10 kt. Humberto is 1319likely to turn toward the northeast and north-northeast at a faster 1320forward speed in 24-36 hours as it interacts with a strong mid-level 1321trough at mid-latitudes to its north and northeast. Later in the 1322forecast period, the track guidance indicates that Humberto will 1323turn back toward the east-northeast as it moves in tandem with the 1324mid-latitude trough over the north Atlantic. The official forecast 1325is in close agreement with the simple and corrected consensus 1326models, TVCA and HCCA. 1327 1328 1329Key Messages: 1330 13311. Hurricane conditions are expected in Bermuda Wednesday night and 1332Thursday morning, with tropical-storm-force winds expected by 1333Wednesday afternoon. Residents there should follow advice given by 1334local officials. 1335 13362. Storm surge and dangerous breaking waves could cause coastal 1337flooding Wednesday night and Thursday along the southern coast of 1338Bermuda. 1339 13403. Swells will continue to affect the northwestern Bahamas and the 1341southeastern coast of the United States from east-central Florida to 1342North Carolina during the next couple of days, creating life- 1343threatening surf and rip current conditions. 1344 1345 1346FORECAST POSITIONS AND MAX WINDS 1347 1348INIT 18/0300Z 31.3N 71.0W 100 KT 115 MPH 1349 12H 18/1200Z 32.0N 68.9W 100 KT 115 MPH 1350 24H 19/0000Z 33.4N 65.5W 100 KT 115 MPH 1351 36H 19/1200Z 36.0N 62.0W 90 KT 105 MPH 1352 48H 20/0000Z 38.6N 60.2W 75 KT 85 MPH 1353 72H 21/0000Z 42.5N 56.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 1354 96H 22/0000Z 44.0N 44.0W 50 KT 60 MPH...POST-TROP/EXTRATROP 1355120H 23/0000Z 49.0N 26.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 1356 1357$$ 1358Forecaster Pasch 1359 1360 1361 1362------------=_1568775374-121860-2926 1363Content-Type: text/plain; charset="US-ASCII" 1364Content-Disposition: inline 1365Content-Transfer-Encoding: 7BIT 1366 1367= = = == = = 1368WTNT44 KNHC 180847 1369TCDAT4 1370 1371Hurricane Humberto Discussion Number 23 1372NWS National Hurricane Center Miami FL AL092019 1373500 AM AST Wed Sep 18 2019 1374 1375Humberto's satellite presentation continues to be outstanding with 1376a large ragged eye and surrounded by deep convection. The eye of the 1377hurricane is very near NOAA Buoy 41048 and most likely will passing 1378over it by the time this advisory is being released. The pressure 1379from the buoy has been dropping fast and is now at 961 mb and the 1380sustained winds have reached 58 kt with gusts to 78 kt. Based on 1381satellite appearance and continuity, the initial intensity is kept 1382at 100 kt. Another Hurricane Hunter aircraft will check the cyclone 1383in a few hours. 1384 1385Some fluctuations in strength due to a potential eyewall replacement 1386are possible during the next 12 to 24 hours or so. After that time 1387very strong southwesterly wind shear should impact the hurricane 1388resulting in weakening. In 72 hours or earlier, the global models 1389show the system merging with a frontal zone, so the NHC forecast 1390calls for extratropical transition by that time. The official 1391intensity forecast follows the corrected consensus HCCA and is not 1392very different from the previous one. 1393 1394Humberto is accelerating, and satellite fixes yield an initial 1395motion toward the east-northeast or 065 degrees at 14 kt. Humberto 1396is located at the base of a strong mid-to upper-level trough, and 1397the hurricane will likely interact with this amplifying trough. This 1398should force Humberto to turn toward the northeast and north- 1399northeast at a faster forward speed in 24-36 hours. Later in the 1400forecast period, the track guidance indicates that Humberto will 1401turn back toward the east-northeast while becoming embedded within 1402the mid-latitude westerlies. The NHC track forecast is very similar 1403to the previous one and is in the middle of the guidance envelope. 1404 1405 1406Key Messages: 1407 14081. Hurricane conditions are expected in Bermuda tonight and Thursday 1409morning, with tropical-storm-force winds expected to begin later 1410today. Residents there should follow advice given by local 1411officials. 1412 14132. Storm surge and dangerous breaking waves could cause coastal 1414flooding tonight and Thursday along the southern coast of Bermuda. 1415 14163. Swells will continue to affect the northwestern Bahamas and the 1417southeastern coast of the United States from east-central Florida to 1418North Carolina during the next couple of days, creating life- 1419threatening surf and rip current conditions. 1420 1421 1422FORECAST POSITIONS AND MAX WINDS 1423 1424INIT 18/0900Z 31.7N 69.6W 100 KT 115 MPH 1425 12H 18/1800Z 32.7N 67.2W 105 KT 120 MPH 1426 24H 19/0600Z 34.8N 63.5W 100 KT 115 MPH 1427 36H 19/1800Z 37.5N 61.0W 85 KT 100 MPH 1428 48H 20/0600Z 40.0N 59.5W 65 KT 75 MPH 1429 72H 21/0600Z 43.0N 53.9W 45 KT 50 MPH...POST-TROP/EXTRATROP 1430 96H 22/0600Z 45.5N 38.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 1431120H 23/0600Z 52.1N 23.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 1432 1433$$ 1434Forecaster Avila 1435 1436 1437 1438------------=_1568796438-121860-3017 1439Content-Type: text/plain; charset="US-ASCII" 1440Content-Disposition: inline 1441Content-Transfer-Encoding: 7BIT 1442 1443= = = == = = 1444WTNT44 KNHC 181444 1445TCDAT4 1446 1447Hurricane Humberto Discussion Number 24 1448NWS National Hurricane Center Miami FL AL092019 14491100 AM AST Wed Sep 18 2019 1450 1451An Air Force Reserve Hurricane Hunter aircraft conducting a 1452reconnoiter of Humberto this morning found that the intensity of the 1453major hurricane had increased slightly, but that the inner-core 64- 1454and 50-kt wind fields had expanded significantly, now extending 1455outward up to at least 90 n mi and 110 n mi, respectively, in the 1456southeastern quadrant. During their pass through the southeastern 1457quadrant, the aircraft measured 700-mb flight-level winds of 120 kt, 1458but peak SFMR winds of only 97 kt. Given that convection is minimal 1459in that quadrant, the normal downward mixing is likely not 1460occurring, the intensity has only been increased to 105 kt. The 1461aircraft also measured a central pressure of 952 mb with a 1462dropsonde, which is close to the pressure of 954.2 mb with 30-kt 1463winds that NOAA buoy 41048 measured in the eye around 0930 UTC. 1464 1465The initial motion estimate remains 065/14 kt. Humberto is beginning 1466to feel the effects of a deep-layer trough approaching from the 1467west, and the hurricane should continue to accelerate toward the 1468east-northeast through tonight, passing just north and northwest 1469of Bermuda, followed by a turn toward the northeast by early 1470Thursday afternoon. By 48 hours or so, Humberto is forecast to turn 1471back toward the east-northeast and maintain that motion through day 14725 as a ridge to the east of the cyclone weakens and flattens out. 1473The new NHC track forecast is very similar to the previous one for 1474the first 36 hours, and then is a little faster and to the left of 1475the previous advisory thereafter, closer to the tightly packed 1476consensus track model guidance. 1477 1478Humberto may have peaked in intensity based on the cloud pattern 1479in satellite imagery beginning to take on the appearance of an 1480extratropical cyclone. Thus, some fluctuations in strength could 1481occur during the next 12 hours or so. Thereafter, very strong 1482southwesterly vertical wind shear and cold upwelling beneath the 1483hurricane should disrupt the inner-core convection and organization, 1484resulting in steady weakening. By 72 hours, the global models 1485continue to show Humberto merging with a frontal system, and the 1486NHC intensity forecast calls for extratropical transition by that 1487time. The official intensity forecast follows the corrected- 1488consensus models HCCA and FSSE through the next 12-24 hours, and 1489then is above that guidance through the remainder of the forecast 1490period, closer to an average of the global models. 1491 1492Key Messages: 1493 14941. A prolonged period of dangerous winds is expected on Bermuda from 1495late this afternoon through Thursday morning, with hurricane-force 1496winds expected overnight tonight. Preparations to protect life and 1497property should be rushed to completion. 1498 14992. Storm surge and dangerous breaking waves could cause coastal 1500flooding tonight and Thursday along the southern coast of Bermuda. 1501 15023. Swells will continue to affect the northwestern Bahamas and the 1503southeastern coast of the United States from east-central Florida to 1504North Carolina during the next couple of days, creating life- 1505threatening surf and rip current conditions. 1506 1507FORECAST POSITIONS AND MAX WINDS 1508 1509INIT 18/1500Z 32.2N 68.1W 105 KT 120 MPH 1510 12H 19/0000Z 33.5N 65.4W 100 KT 115 MPH 1511 24H 19/1200Z 36.1N 62.1W 90 KT 105 MPH 1512 36H 20/0000Z 38.6N 60.5W 75 KT 85 MPH 1513 48H 20/1200Z 40.7N 59.5W 60 KT 70 MPH 1514 72H 21/1200Z 43.3N 50.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 1515 96H 22/1200Z 47.2N 33.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 1516120H 23/1200Z 54.0N 20.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 1517 1518$$ 1519Forecaster Stewart 1520 1521 1522 1523------------=_1568817862-2010-68 1524Content-Type: text/plain; charset="US-ASCII" 1525Content-Disposition: inline 1526Content-Transfer-Encoding: 7BIT 1527 1528= = = == = = 1529WTNT44 KNHC 182052 1530TCDAT4 1531 1532Hurricane Humberto Discussion Number 25 1533NWS National Hurricane Center Miami FL AL092019 1534500 PM AST Wed Sep 18 2019 1535 1536Normal communications with the Bermuda Weather Service have been 1537disrupted due to a lightning strike. 1538 1539Humberto is taking on more of a hybrid-extratropical structure based 1540on most of the rain shield having been displaced to the left or 1541poleward side of the circulation now as seen in Bermuda weather 1542radar data, and also in conventional and passive microwave satellite 1543imagery. Sustained hurricane-force winds and gusts have been 1544measured by amateur radio operators across the island, with a peak 1545gust to 104 mph having been reported thus far at Ports Island, 1546Bermuda. The initial intensity of 105 kt on the previous advisory 1547has been maintained since little overall change in the structure has 1548occurred since the last aircraft reconnaissance mission 6 hours ago. 1549 1550The initial motion estimate is 060/17 kt. There are no significant 1551changes to the previous forecast track or reasoning. Humberto has 1552basically remained on track during the past 24 hours. The hurricane 1553is expected to continue accelerating toward the east-northeast 1554tonight and Thursday morning, with the center expected to pass 1555about 80 nmi northwest of Bermuda early this evening. A turn toward 1556the northeast and north-northeast is forecast to occur by early 1557Thursday afternoon, followed by a motion toward the east-northeast 1558by 48 hours, with the latter motion continuing through 96 hours. The 1559new official track forecast is similar to the previous advisory 1560track, and lies close to the tightly packed TVCN, NOAA-HCCA, and 1561FSSE consensus track models. 1562 1563Humberto is now fully embedded within an anticyclonically curved 1564right-rear jet entrance region. As a result, some fluctuations in 1565strength could occur during the next 12 hours or so. Thereafter, 1566strong southwesterly vertical wind shear in excess of 50 kt, along 1567with cold upwelling beneath the hurricane, should combine to induce 1568steady weakening. By 48 hours, the global models continue to 1569forecast Humberto to merge with a frontal system, and the NHC 1570intensity forecast calls for extratropical transition around that 1571time. The official intensity forecast follows an average of the 1572global models' intensity forecasts due to Humberto's hybrid nature, 1573which is not being captured properly by the tropical-cyclone-based 1574consensus intensity models. 1575 1576Key Messages: 1577 15781. A prolonged period of dangerous winds is expected to continue on 1579Bermuda through Thursday morning, with hurricane-force winds 1580expected during the next several hours. Preparations to protect 1581life and property should be rushed to completion. 1582 15832. Storm surge and dangerous breaking waves could cause coastal 1584flooding tonight and Thursday along the southern coast of Bermuda. 1585 15863. Swells will continue to affect the northwestern Bahamas and the 1587southeastern coast of the United States from east-central Florida to 1588North Carolina during the next couple of days, creating life- 1589threatening surf and rip current conditions. 1590 1591FORECAST POSITIONS AND MAX WINDS 1592 1593INIT 18/2100Z 33.0N 66.3W 105 KT 120 MPH 1594 12H 19/0600Z 34.6N 63.6W 105 KT 120 MPH 1595 24H 19/1800Z 37.4N 61.0W 95 KT 110 MPH 1596 36H 20/0600Z 39.8N 60.0W 75 KT 85 MPH 1597 48H 20/1800Z 41.6N 58.7W 60 KT 70 MPH...POST-TROP/EXTRATROP 1598 72H 21/1800Z 43.9N 47.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 1599 96H 22/1800Z 49.0N 30.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 1600120H 23/1800Z...DISSIPATED/ABSORBED 1601 1602$$ 1603Forecaster Stewart 1604 1605 1606 1607------------=_1568839947-2010-217 1608Content-Type: text/plain; charset="US-ASCII" 1609Content-Disposition: inline 1610Content-Transfer-Encoding: 7BIT 1611 1612= = = == = = 1613WTNT44 KNHC 190255 1614TCDAT4 1615 1616Hurricane Humberto Discussion Number 26 1617NWS National Hurricane Center Miami FL AL092019 16181100 PM AST Wed Sep 18 2019 1619 1620Normal communications with the Bermuda Weather Service have been 1621restored. However, the weather radar on Bermuda is currently down. 1622 1623The center of Humberto made its closest approach to Bermuda a few 1624hours ago, with many weather stations on the island reporting 1625sustained hurricane force winds and gusts near or over 100 kt. 1626Since that time, an Air Force Reserve Hurricane Hunter aircraft has 1627arrived at the storm and reported little change in strength despite 1628a decaying appearance in satellite imagery. The SFMR surface wind 1629estimates were in the 100-105 kt range to the west of the center, 1630and the central pressure was near 952 mb. Based on these data, 1631the initial intensity is held at a possibly conservative 105 kt. 1632 1633The decay in the satellite signature is due to Humberto starting to 1634undergo extratropical transition, a process that the global models 1635forecast to be complete by 36 h. Those models forecast that the 1636cyclone should steadily weaken during and after the transition 1637until it is absorbed by another low pressure system between 96-120 1638h, and the intensity forecast follows this scenario. The new 1639intensity forecast is basically an update of the previous forecast, 1640with a slightly faster decrease in intensity during the first 48 h. 1641 1642The initial motion is now 055/20. Humberto is forecast to turn 1643north-northeastward as it becomes extratropical, followed by a turn 1644back toward the east-northeastward as the extratropical low is 1645steered by the mid-latitude westerlies. The track guidance 1646remains tightly clustered, and the new forecast track has only 1647minor adjustments from the previous forecast. 1648 1649 1650Key Messages: 1651 16521. Tropical-storm conditions on Bermuda should subside during the 1653next several hours. 1654 16552. Storm surge and dangerous breaking waves, while diminishing, 1656could cause coastal flooding tonight and Thursday along the coast of 1657Bermuda. 1658 16593. Swells will continue to affect the northwestern Bahamas and the 1660southeastern coast of the United States from east-central Florida to 1661North Carolina during the next couple of days, creating life- 1662threatening surf and rip current conditions. 1663 1664 1665FORECAST POSITIONS AND MAX WINDS 1666 1667INIT 19/0300Z 34.0N 63.9W 105 KT 120 MPH 1668 12H 19/1200Z 35.8N 61.6W 95 KT 110 MPH 1669 24H 20/0000Z 38.5N 59.8W 85 KT 100 MPH 1670 36H 20/1200Z 40.7N 58.8W 70 KT 80 MPH...POST-TROP/EXTRATROP 1671 48H 21/0000Z 42.4N 56.1W 55 KT 65 MPH...POST-TROP/EXTRATROP 1672 72H 22/0000Z 45.0N 41.7W 45 KT 50 MPH...POST-TROP/EXTRATROP 1673 96H 23/0000Z 50.0N 25.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 1674120H 24/0000Z...DISSIPATED 1675 1676$$ 1677Forecaster Beven 1678 1679 1680 1681------------=_1568861729-2010-366 1682Content-Type: text/plain; charset="US-ASCII" 1683Content-Disposition: inline 1684Content-Transfer-Encoding: 7BIT 1685 1686= = = == = = 1687WTNT44 KNHC 190853 1688TCDAT4 1689 1690Hurricane Humberto Discussion Number 27 1691NWS National Hurricane Center Miami FL AL092019 1692500 AM AST Thu Sep 19 2019 1693 1694Flight-level and surface wind observations reported by Air Force 1695Reserve Hurricane Hunter aircraft exiting Humberto a couple of hours 1696ago indicated that the maximum sustained winds have increased to 110 1697kt. However, weakening is expected to commence soon. 1698 1699Humberto's extratropical transition continues as a high amplitude PV 1700tongue, noted in the GOES-16 water vapor imagery, and associated dry 1701air, digs into the backside of the cyclone. The large-scale models, 1702as well as the FSU Cyclone Phase Evolution forecast, indicate that 1703the process will be completed in less than 36 hours. Afterward, 1704gradual weakening is expected until the extratropical low is 1705absorbed by another larger low pressure system, moving out of 1706Atlantic Canada, by the end of the forecast period. The NHC 1707intensity forecast is basically an update of the previous forecast 1708and is based on a blend of the global models beyond the 36 hour 1709period. 1710 1711The initial motion is estimated to be northeastward, or 045/19 kt. 1712Humberto is forecast to turn north-northeastward as the cyclone 1713completes its extratropical transition, followed by a turn 1714back toward the east-northeast within the strong deep-layer 1715mid-latitude westerlies. The NHC forecast is nudged a little to the 1716left of the previous advisory between the 36 and 72 hour periods, 1717and is close to the NOAA HFIP HCCA consensus model. 1718 1719Key Messages: 1720 17211. Storm surge and dangerous breaking waves, while diminishing, 1722could cause coastal flooding today along the coast of Bermuda. 1723 17242. Swells will continue to affect the northwestern Bahamas and the 1725southeastern coast of the United States from east-central Florida to 1726North Carolina during the next couple of days, creating life- 1727threatening surf and rip current conditions. 1728 1729 1730FORECAST POSITIONS AND MAX WINDS 1731 1732INIT 19/0900Z 35.2N 62.2W 110 KT 125 MPH 1733 12H 19/1800Z 37.4N 60.0W 95 KT 110 MPH 1734 24H 20/0600Z 39.9N 58.9W 75 KT 85 MPH 1735 36H 20/1800Z 41.8N 57.4W 60 KT 70 MPH...POST-TROP/EXTRATROP 1736 48H 21/0600Z 43.2N 53.4W 50 KT 60 MPH...POST-TROP/EXTRATROP 1737 72H 22/0600Z 46.3N 36.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 1738 96H 23/0600Z...DISSIPATED 1739 1740$$ 1741Forecaster Roberts 1742 1743 1744 1745------------=_1568883212-2010-491 1746Content-Type: text/plain; charset="US-ASCII" 1747Content-Disposition: inline 1748Content-Transfer-Encoding: 7BIT 1749 1750= = = == = = 1751WTNT44 KNHC 191450 1752TCDAT4 1753 1754Hurricane Humberto Discussion Number 28 1755NWS National Hurricane Center Miami FL AL092019 17561100 AM AST Thu Sep 19 2019 1757 1758Humberto is still a powerful hurricane, but the system is in the 1759process of transitioning to an extratropical cyclone. Satellite 1760images indicate that frontal features have formed, and cooler and 1761drier air is wrapping around the western and southern sides of the 1762circulation. Deep convection is most organized to the north and 1763west of the partially exposed low-level center. The initial 1764intensity is lowered to 95 kt for this advisory. 1765 1766A mid- to upper-level low situated just west of Humberto has been 1767aiding in its transition, and the global models suggest that 1768Humberto will become fully extratropical later today. Despite the 1769fact that the cyclone is expected to lose its tropical 1770characteristics, it is still forecast to produce winds of 1771hurricane-force for another 36 hours or so. 1772 1773Humberto is moving northeastward at 21 kt. A turn to the 1774north-northeast with a decrease in forward speed is expected later 1775today and tonight as Humberto rotates around the north side of the 1776mid- to upper-level low. After that, a faster east-northeast or 1777east motion is expected, as the system becomes embedded in the 1778mid-latitude westerlies. The cyclone should be absorbed by 1779another extratropical low in about 3 days over the far north 1780Atlantic. 1781 1782Key Messages: 1783 17841. Large swells will continue to affect Bermuda, the northwestern 1785Bahamas, and the east coast of the United States from east-central 1786Florida to the Mid-Atlantic States during the next couple of days. 1787These swells could create life-threatening surf and rip current 1788conditions. 1789 1790 1791FORECAST POSITIONS AND MAX WINDS 1792 1793INIT 19/1500Z 36.8N 60.0W 95 KT 110 MPH 1794 12H 20/0000Z 38.8N 58.9W 90 KT 105 MPH...POST-TROP/EXTRATROP 1795 24H 20/1200Z 41.2N 57.6W 80 KT 90 MPH...POST-TROP/EXTRATROP 1796 36H 21/0000Z 43.2N 54.8W 65 KT 75 MPH...POST-TROP/EXTRATROP 1797 48H 21/1200Z 44.6N 49.3W 55 KT 65 MPH...POST-TROP/EXTRATROP 1798 72H 22/1200Z...DISSIPATED 1799 1800$$ 1801Forecaster Cangialosi 1802 1803 1804 1805------------=_1568904632-2010-628 1806Content-Type: text/plain; charset="US-ASCII" 1807Content-Disposition: inline 1808Content-Transfer-Encoding: 7BIT 1809 1810= = = == = = 1811WTNT44 KNHC 192033 1812TCDAT4 1813 1814Hurricane Humberto Discussion Number 29 1815NWS National Hurricane Center Miami FL AL092019 1816500 PM AST Thu Sep 19 2019 1817 1818Humberto is almost a post-tropical cyclone. Satellite images show 1819a well-defined cold and warm front, but they do not appear to be 1820fully connected to the center of circulation yet. In addition, the 1821cyclone is still producing an area of deep convection to 1822the northwest of the exposed low-level center. ASCAT data from 1823earlier today indicated that the wind field of Humberto is very 1824large with tropical-storm-force winds extending up to 330 n mi from 1825the center and hurricane-force winds extending out to 70 n mi from 1826the center. The initial intensity is lowered a little to 90 kt for 1827this advisory. 1828 1829The cyclone is anticipated to become fully extratropical soon, 1830within the next 6 to 12 hours. Although weakening is forecast, 1831Humberto is expected to be a large and powerful extratropical 1832cyclone for a couple of days before it is absorbed by another 1833extratropical low over the north Atlantic. The NHC intensity 1834forecast generally follows the guidance of the GFS model, which 1835typically handles extratropical lows better than the tropical 1836cyclone intensity guidance. 1837 1838Humberto is moving northeastward at 21 kt. A slight turn to the 1839left and a decrease in forward speed are expected during the next 184012 to 24 hours as the cyclone rotates around the east and north 1841sides of a mid- to upper-level low to its west. After that time, a 1842faster east-northeast or east motion is expected when the cyclone 1843becomes embedded in the mid-latitude westerlies. The NHC track 1844forecast is largely an update of the previous one and near the 1845various consensus aids. 1846 1847Key Messages: 1848 18491. Large swells will continue to affect Bermuda, the northwestern 1850Bahamas, and the east coast of the United States from east-central 1851Florida to the Mid-Atlantic States during the next couple of days. 1852These swells could create life-threatening surf and rip current 1853conditions. 1854 1855 1856FORECAST POSITIONS AND MAX WINDS 1857 1858INIT 19/2100Z 38.5N 58.7W 90 KT 105 MPH 1859 12H 20/0600Z 40.4N 57.5W 75 KT 85 MPH...POST-TROP/EXTRATROP 1860 24H 20/1800Z 42.8N 55.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 1861 36H 21/0600Z 44.6N 51.2W 55 KT 65 MPH...POST-TROP/EXTRATROP 1862 48H 21/1800Z 45.6N 44.6W 50 KT 60 MPH...POST-TROP/EXTRATROP 1863 72H 22/1800Z...DISSIPATED 1864 1865$$ 1866Forecaster Cangialosi 1867 1868 1869 1870------------=_1568925249-2010-826 1871Content-Type: text/plain; charset="US-ASCII" 1872Content-Disposition: inline 1873Content-Transfer-Encoding: 7BIT 1874 1875= = = == = = 1876