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Hurricane Michael Forecast Discussion Number 8
2018-10-08 16:38:51| National Hurricane Center (Atlantic)
Issued at 1100 AM EDT Mon Oct 08 2018 000 WTNT44 KNHC 081438 TCDAT4 Hurricane Michael Discussion Number 8 NWS National Hurricane Center Miami FL AL142018 1100 AM EDT Mon Oct 08 2018 The satellite presentation of Michael has continued to improve overnight and this morning, with the center well embedded within an area of cold cloud tops. An eye is becoming apparent in visible imagery, and this was also confirmed by a recent SSMIS microwave overpass and the Air Force Reserve reconnaissance aircraft. The aircraft reported a minimum pressure around 982 mb during the most recent pass through the center, and also found flight-level winds that support upgrading Michael to a a 65-kt hurricane for this advisory. Although the outflow is still somewhat restricted over the western portion of the circulation, it has been expanding in that direction. The global models suggest that the shear will relax a little more while the hurricane moves over the very warm waters of the southeastern Gulf of Mexico. Now that Michael has developed an inner core, steady to rapid strengthening is predicted during the next 24 to 36 hours. The SHIPS Rapid Intensification Index and DTOPS give a 55-60 percent chance of rapid intensification during the next 24 hours. The updated NHC forecast is near the upper-end of the guidance and calls for rapid strengthening over the next 24 hours, and brings Michael to major hurricane status. After that time, most of the intensity guidance slows down the rate of intensification, perhaps due to a slight increase in southwesterly shear. Weakening is expected after landfall, but the forecast track keeps a portion of the circulation over water along the southeast U.S. coast, so Michael is predicted to remain a tropical storm through 72 hours. The system should become a powerful extratropical low off the U.S. Mid-Atlantic coast in about 4 days. Reconnaissance aircraft fixes indicate that Michael is still moving a little east of due north. The hurricane should move northward or north-northwestward over the next couple of days while the storm crosses the eastern Gulf of Mexico. By 48 hours, Michael should turn northeastward ahead of a trough moving into the central United States. The cross-track spread in the guidance has decreased since yesterday, but there continue to be differences in how fast Michael moves northward over the Gulf of Mexico. The HWRF and GFS remain among the faster models, while the ECMWF is still much slower. The NHC track is along the eastern side of the guidance through 24 hours due to the recent motion of the storm, and is remains near the various consensus aids after that time. The post-tropical portion of the track and intensity forecast is based on guidance provided by the Ocean Prediction Center. Key Messages: 1. Michael is forecast to be a dangerous major hurricane when it reaches the northeastern Gulf Coast on Wednesday, and life- threatening storm surge is possible along portions of the Florida Gulf Coast regardless of the storm's exact track or intensity. Residents in the storm surge and hurricane watch areas should follow any advice given by local officials, as storm surge and hurricane warnings will likely be issued later today. 2. Heavy rainfall from Michael could produce life-threatening flash flooding from the Florida Panhandle and Big Bend region into portions of the Carolinas through Thursday. 3. Hurricane conditions will spread over portions of western Cuba this afternoon, where a hurricane warning is now in effect. Tropical storm conditions are expected over the northeastern Yucatan Peninsula and the Isle of Youth today. 4. Michael is expected to produce heavy rainfall and flash flooding over portions of western Cuba and the northeastern Yucatan Peninsula of Mexico during the next couple of days. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 21.2N 84.9W 65 KT 75 MPH 12H 09/0000Z 22.6N 85.3W 85 KT 100 MPH 24H 09/1200Z 24.4N 85.9W 95 KT 110 MPH 36H 10/0000Z 26.4N 86.4W 105 KT 120 MPH 48H 10/1200Z 28.6N 86.1W 105 KT 120 MPH 72H 11/1200Z 33.0N 82.5W 45 KT 50 MPH...INLAND 96H 12/1200Z 37.8N 73.6W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 13/1200Z 42.8N 59.0W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown
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