000 WTNT45 KNHC 020852 TCDAT5 Hurricane Dorian Discussion Number 36 NWS National Hurricane Center Miami FL AL052019 500 AM EDT Mon Sep 02 2019 Satellite imagery continues to show that Dorian has an extremely well-defined eye embedded within very cold cloud tops. The diameter of the eye appears to have expanded to near 20 n mi, and radar data, especially from the Bahamas Department of Meteorology radar, show that there are concentric eyewalls. The hurricane also continues to exhibit strong upper-tropospheric outflow. The initial intensity estimate has been reduced to 145 kt, which lies between earlier Hurricane Hunter estimates and satellite intensity estimates from TAFB and SAB. This lowering of intensity is consistent with the development of a concentric eyewall. During the next few days, Dorian should be encountering some increase in shear, which will likely result in weakening. However it is anticipated that the system will remain a dangerous major hurricane for the next several days. The official intensity forecast lies between the statistical-dynamical guidance and the corrected multi-model consensus. Steering currents have weakened, and Dorian has almost come to a standstill over eastern Grand Bahama Island, with an initial motion of 270/1 kt. The mid-tropospheric high to the north of the hurricane that had been steering Dorian westward has collapsed. Global models indicate that, in a couple of days, a weakness in the ridge will develop along 75W-80W. This would likely cause Dorian to move northwestward to northward toward and through this weakness. Later in the forecast period, the system is expected to accelerate northeastward on the southern side of a broad mid-tropospheric trough. The official track forecast is very close to the previous one and to the corrected dynamical model consensus, HCCA. Although the official forecast does not show Dorian making landfall along the Florida east coast, it is still possible for the hurricane to deviate from this forecast, and move very near or over the coast. Users are reminded not to focus on the exact forecast track. Key Messages: 1. A prolonged period of catastrophic winds and storm surge will continue to affect Grand Bahama Island through today and tonight. Everyone there should remain in shelter and not venture into the eye. 2. Life-threatening storm surges and dangerous hurricane-force winds are expected along portions of the Florida east coast through mid-week, and storm surge and hurricane warnings are in effect. Only a slight deviation to the left of the official forecast would bring the core of Dorian near or over the Florida east coast. Residents should listen to advice given by local emergency officials. 3. There is an increasing likelihood of strong winds and dangerous storm surge along the coasts of Georgia, South Carolina, and North Carolina later this week. Residents in these areas should continue to monitor the progress of Dorian and listen to advice given by local emergency officials. 4. Heavy rains, capable of producing life-threatening flash floods, are expected over northern portions of the Bahamas and coastal sections of the Southeast and lower Mid-Atlantic regions of the United States into Friday. FORECAST POSITIONS AND MAX WINDS INIT 02/0900Z 26.6N 78.2W 145 KT 165 MPH 12H 02/1800Z 26.7N 78.7W 140 KT 160 MPH 24H 03/0600Z 26.9N 79.0W 130 KT 150 MPH 36H 03/1800Z 27.6N 79.5W 120 KT 140 MPH 48H 04/0600Z 28.7N 80.0W 110 KT 125 MPH 72H 05/0600Z 31.3N 79.8W 100 KT 115 MPH 96H 06/0600Z 34.5N 76.5W 85 KT 100 MPH 120H 07/0600Z 38.5N 70.0W 75 KT 85 MPH $$ Forecaster Pasch