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Hurricane Michael Forecast Discussion Number 13
2018-10-09 22:55:30| National Hurricane Center (Atlantic)
Issued at 400 PM CDT Tue Oct 09 2018 000 WTNT44 KNHC 092055 TCDAT4 Hurricane Michael Discussion Number 13 NWS National Hurricane Center Miami FL AL142018 400 PM CDT Tue Oct 09 2018 The eye of Michael became very distinct in both visible and infrared satellite pictures early this afternoon, but has been a little more cloud filled since that time. Very deep convection has continue to develop over the southeastern and eastern portion of the eyewall and rotate around the north and west sides. An Air Force Reserve reconnaissance aircraft measured a peak 700-mb flight-level wind of 109 kt in the northeast eyewall as it exited the storm just prior to 1800 UTC, and another Air Force Hurricane Hunter very recently made its first pass through the eye and reported similar flight-level winds in the southeast quadrant, and a minimum pressure of 957 mb, down about 8 mb over the past few hours. Based on these observations and Dvorak satellite classifications of 115 kt and 102 kt from SAB and TAFB, respectively, the initial intensity has been increased to 105 kt for this advisory. The environment ahead of Michael is expected to remain conducive for additional strengthening during the next 12 to 18 hours. There may be some increase in southwesterly shear as the hurricane nears the Gulf Coast, but it is not likely to result in a significant decrease in intensity before landfall. The global models continue to deepen the cyclone over the Gulf, increasing the confidence that some additional intensification will occur. The new NHC intensity forecast brings Michael up to 110 kt, and is in best agreement with the SHIPS and HCCA models. After landfall, significant weakening should occur while Michael moves over the southeastern United States, but the cyclone is predicted to re-strengthen over the western Atlantic due to baroclinic processes after it merges with a front and becomes extratropical on Friday. Michael is still moving north-northwestward to northward at about 10 kt. The hurricane should turn due northward this evening, then northeastward on Wednesday as a trough moves into the central United States. Michael should become embedded within the westerlies in 48 to 72 hours, and then accelerate northeastward to east- northeastward over the western and central-north Atlantic over the weekend. There is not much spread in the dynamical model guidance, and little change was required to the official forecast. Although the NHC forecast brings the center onshore Wednesday afternoon, conditions will deteriorate along the northeastern Gulf Coast tonight. Tropical storm watches and warnings have been expanded northward along the U.S. East Coast from northeastern Florida to North Carolina. Non-tropical watches, warnings, and advisories will be issued by local NWS offices for wind hazards north of Duck, North Carolina, as Michael is expected to be post-tropical when it affects those areas. Key Messages: 1. Life-threatening storm surge is likely along portions of the coasts of the Florida Panhandle, Big Bend, and Nature Coast, where a storm surge warning is in effect. The worst storm surge is expected between Mexico Beach and Keaton Beach, where 9 to 13 feet of inundation is possible. Water levels will rise well in advance of the center of Michael, and residents within the storm surge warning area should finish preparations to protect life and property today. 2. Everyone in the hurricane warning area along the Florida Gulf Coast should prepare for life-threatening major hurricane winds associated with the core of Michael. Hurricane force winds will also extend well inland across portions of the Florida Panhandle, southern Georgia, and southeast Alabama as Michael moves inland. 3. Heavy rainfall from Michael could produce life-threatening flash flooding from the Florida Panhandle and Big Bend region into portions of Georgia, the Carolinas, and southeast Virginia. 4. Tropical storm conditions will likely affect portions of the southeast U.S. coast from northeast Florida through North Carolina, and tropical storm watches and warnings have been issued for these areas. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 26.0N 86.4W 105 KT 120 MPH 12H 10/0600Z 27.6N 86.6W 110 KT 125 MPH 24H 10/1800Z 29.7N 85.9W 110 KT 125 MPH 36H 11/0600Z 31.8N 84.1W 60 KT 70 MPH...INLAND 48H 11/1800Z 33.9N 81.0W 45 KT 50 MPH...INLAND 72H 12/1800Z 39.0N 70.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 96H 13/1800Z 45.5N 51.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 14/1800Z 50.0N 30.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Brown
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