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#944223 (Received by flhurricane at: 4:56 PM 11.Oct.2018) TCDAT4 Tropical Storm Michael Discussion Number 21 NWS National Hurricane Center Miami FL AL142018 500 PM EDT Thu Oct 11 2018 Satellite and radar data show that Michael's rain shield is beginning to expand northward and northwestward, and that cooler and drier air is starting to wrap around the western portion of the circulation. These trends indicate that Michael's transition to an extratropical low has started. There have been recent observations of 40 to nearly 45 kt sustained winds along the southeastern coast of North Carolina, so the initial intensity remains 45 kt. Little change in strength is expected through this evening, but Michael is forecast to quickly intensify after it completes extratropical transition and exits the east coast of the United States tonight. The official intensity forecast is based on guidance from the NOAA Ocean Prediction Center. It should also be noted that an area of damaging wind gusts of up to 50 kt has developed around the northwest side of the circulation over central North Carolina and Virginia this afternoon. As a result, the gust factor has been increased in this advisory, as this area of strong winds will spread northward and eastward across portions of eastern Virginia and northeastern North Carolina this evening and tonight. Michael is moving northeastward or 050/21 kt. The storm will continue to accelerate as it become further embedded within the mid-latitude westerlies. The post-tropical cyclone will race across the north Atlantic during the next few days, before slowing down late in the period before it weakens and dissipates. The track guidance continues to be in good agreement and little change was required from the previous NHC track forecast. Gale- to storm-force winds are expected over portions of the Mid-Atlantic coast as Michael exits the U.S. east coast and becomes post-tropical. Non-tropical high wind watches, warnings, and advisories have been issued by local NWS offices for wind hazards in these areas north of Duck, North Carolina. Key Messages: 1. Life-threatening flash flooding is occurring over portions of North Carolina and southern Virginia and will continue through the evening. 2. Damaging winds are spreading eastward across portions of central and eastern North Carolina, and will continue through this evening. These winds have the potential to cause tree and structural damage. Strong winds are also expected over portions of southeastern Virginia and the Virginia Eastern Shore tonight as Michael becomes post-tropical. 3. Dangerous storm surge is possible tonight along the sound side of the North Carolina Outer Banks from Ocracoke Inlet to Duck, where a Storm Surge Watch is in effect. FORECAST POSITIONS AND MAX WINDS INIT 11/2100Z 36.1N 78.8W 45 KT 50 MPH...INLAND 12H 12/0600Z 38.1N 74.7W 45 KT 50 MPH...POST-TROP/EXTRATROP 24H 12/1800Z 41.2N 66.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 36H 13/0600Z 44.5N 55.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 13/1800Z 47.0N 42.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 72H 14/1800Z 48.5N 17.5W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 15/1800Z 46.5N 7.0W 30 KT 35 MPH...POST-TROP/EXTRATROP 120H 16/1800Z...DISSIPATED $$ Forecaster Brown |