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#980861 (Received by flhurricane at: 5:12 AM 04.Sep.2019) TCDAT5 Hurricane Dorian Discussion Number 44 NWS National Hurricane Center Miami FL AL052019 500 AM EDT Wed Sep 04 2019 NOAA Doppler radar data and reports from an Air Force Reserve Unit Hurricane Hunter aircraft indicate that Dorian`s eye has become broad and less well-defined over the past several hours. The hurricane is still producing some healthy bands of deep convection that are causing winds of at least tropical storm force along portions of the northeast coast of Florida. Although the central pressure had been rising, recent observations from the Hurricane Hunters show that it has leveled off near 963 mb. The current intensity is set at 90 kt, which may be generous considering the flight-level wind speeds reported by the aircraft. Dorian will be traversing warm waters for the next couple of days, with some increase in vertical shear after 24 hours. The official intensity forecast maintains the current intensity for a day or so and then shows a very slow weakening thereafter. This is close to the latest statistical-dynamical guidance. The system is expected to maintain close to category 2 strength until it passes near or over the North Carolina Outer Banks. Dorian is moving slowly north-northwestward to northwestward, or 330/7 kt. There is basically no change to the track forecast reasoning. Over the next day or so, the hurricane is forecast to gradually turn toward the north as it moves through a break in the subtropical ridge. Thereafter, Dorian should accelerate north-northeastward to northeastward on the southern side of a broad mid-latitude trough. The official forecast track remains close to the corrected multi-model consensus. Since the NHC track prediction continues to take Dorian dangerously close to the southeast U.S. coast, all interests from northeast Florida to the Carolinas should remain vigilant to the possibility of experiencing destructive winds, flooding rains, and life-threatening storm surges from this hurricane. Key Messages: 1. Life-threatening storm surge and dangerous winds are expected along portions of the Florida east coast and the coasts of Georgia, South Carolina, and North Carolina, regardless of the exact track of Dorian`s center. Water levels could rise well in advance of the arrival of strong winds. Residents in these areas should follow advice given by local emergency officials. 2. The risk of wind and rain impacts along portions of the Virginia coast and the southern Chesapeake Bay are increasing. Residents in these areas should continue to monitor the progress of Dorian. 3. The flash flood threat will spread up the southeast U.S. coast today and Thursday, then across the coastal Mid-Atlantic region on Friday. There is a high risk of flash flooding on Thursday across coastal sections from northeast South Carolina into southern North Carolina. FORECAST POSITIONS AND MAX WINDS INIT 04/0900Z 29.2N 79.5W 90 KT 105 MPH 12H 04/1800Z 30.1N 79.8W 90 KT 105 MPH 24H 05/0600Z 31.2N 80.0W 90 KT 105 MPH 36H 05/1800Z 32.2N 79.4W 85 KT 100 MPH 48H 06/0600Z 33.7N 77.7W 80 KT 90 MPH 72H 07/0600Z 38.0N 70.6W 75 KT 85 MPH 96H 08/0600Z 45.0N 61.5W 70 KT 80 MPH...POST-TROP/EXTRATROP 120H 09/0600Z 53.5N 50.0W 60 KT 70 MPH...POST-TROP/EXTRATROP $$ Forecaster Pasch |