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| #980150 (Received by flhurricane at: 10:48 PM 30.Aug.2019) TCDAT5 Hurricane Dorian Discussion Number 27 NWS National Hurricane Center Miami FL AL052019 1100 PM EDT Fri Aug 30 2019 The cloud pattern of Dorian has become quite impressive in infrared satellite imagery this evening. The eye has become very distinct and is surrounded by a very symmetric ring of deep convection. The upper-level outflow has also improved. A NOAA Hurricane Hunter aircraft this evening has measured peak SFMR winds of 119 kt, and a dropsonde dropped in the northeastern eyewall had mean winds in the lowest 150 m that also supported winds of 118 kt, so the initial wind speed has been raised to 120 kt. The latest center drop indicates a minimum pressure of around 948 mb, down 22 mb since this afternoon. Since Dorian will be traversing SSTs of around 29C and remain in a low shear environment, the current intensification phase may not be over. The NHC forecast is above the guidance and calls for some additional strengthening in the short-term. After that, fluctuations in intensity are likely due to eyewall replacement cycles that are difficult to predict. Although some decrease in wind speed could occur when Dorian slows down and causes some upwelling, all indications are that Dorian will remain an extremely powerful hurricane for the next several days. The hurricane is moving west-northwestward or 300 degrees at 9 kt. The ridge to the north of Dorian is expected to build during the next 24 hours, and this should cause Dorian`s heading to bend westward toward the northwestern Bahamas. After 48 hours, the global models show an erosion of the western portion of the ridge, which is expected to cause the steering currents to collapse and the hurricane to slow down considerably by day 3. Later in the period, the models have again trended to a more significant weakness in the ridge which allows Dorian to turn northwestward, then northward near the east coast of Florida. Although the deterministic versions of the global models have trended northeastward again, the GFS and UKMET ensemble means are farther to the left. The updated NHC track forecast has been nudged northeastward and lies between the multi-model consensus aids and the aforementioned ensemble means. Although the official forecast track has been nudged northeastward to near the east coast of Florida the risk of significant impacts over much of the Florida peninsula remains high. Key Messages: 1. A prolonged period of life-threatening storm surge and devastating hurricane-force winds are likely in portions of the northwestern Bahamas, where a hurricane warning is in effect. Residents should execute their hurricane plan and listen to advice given by local emergency officials. 2. Life-threatening storm surge and devastating hurricane-force winds are possible along portions of the Florida east coast by early next week, but since Dorian is forecast to slow down and turn northward near the coast, it is too soon to determine when or where the highest surge and winds will occur. Residents should have their hurricane plan in place, know if they are in a hurricane evacuation zone, and listen to advice given by local emergency officials. 3. A prolonged period of storm surge, high winds, and rainfall is possible in portions of Florida into next week, including the possibility of hurricane-force winds over inland portions of the Florida peninsula. 4. Heavy rains, capable of life-threatening flash floods, are expected over portions of the Bahamas and coastal sections of the southeastern United States this weekend through much of next week. FORECAST POSITIONS AND MAX WINDS INIT 31/0300Z 25.5N 71.4W 120 KT 140 MPH 12H 31/1200Z 25.9N 72.8W 130 KT 150 MPH 24H 01/0000Z 26.3N 74.5W 130 KT 150 MPH 36H 01/1200Z 26.6N 76.0W 125 KT 145 MPH 48H 02/0000Z 26.8N 77.3W 125 KT 145 MPH 72H 03/0000Z 27.0N 78.6W 115 KT 130 MPH 96H 04/0000Z 28.3N 80.5W 110 KT 125 MPH 120H 05/0000Z 30.8N 81.2W 90 KT 105 MPH $$ Forecaster Brown |
