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Tropical Storm Michael Forecast Discussion Number 22
2018-10-12 04:53:49| National Hurricane Center (Atlantic)
Issued at 1100 PM EDT Thu Oct 11 2018 000 WTNT44 KNHC 120253 TCDAT4 Tropical Storm Michael Discussion Number 22 NWS National Hurricane Center Miami FL AL142018 1100 PM EDT Thu Oct 11 2018 Michael has just about lost its tropical characteristics. The low-level circulation is becoming increasingly elongated as it becomes embedded within a frontal zone, and the center is becoming ill defined. The center we have been tracking across North Carolina appears to have moved into extreme southeastern Virginia, although it should be noted that a second low center, one with even lower pressure, has formed farther north along the western shore of Chesapeake Bay, closer to the deepest convection. Needless to say, Michael has just about become post-tropical, and that transformation should be complete overnight. The estimated maximum winds remain 45 kt based on recent observations from coastal North Carolina. Due to baroclinic forcing, some re-intensification of the post-tropical low is expected during the next 24-36 hours, following guidance from the Ocean Prediction Center. The post-tropical low should then begin to weaken again in 2-3 days and will likely be absorbed by another weather system to the west of Europe by day 4. The initial motion based on the continuity-following low center is northeastward, or 055/22 kt. Michael is embedded within the mid-latitude flow and is therefore expected to accelerate toward the east-northeast over the western and northern Atlantic during the next couple of days, even approaching speeds of about 50 kt in 48 hours. The track guidance remains tightly clustered, and no significant changes to the official track forecast were required. Michael's center is expected to move off the coast of Virginia within the next couple of hours, with tropical-storm- and gale-force winds moving away from the coast during the day on Friday. 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 the southern Mid-Atlantic states and will continue overnight. 2. Strong, possibly damaging winds are expected over portions of extreme eastern North Carolina, southeastern Virginia, and the southern Delmarva peninsula overnight. These winds have the potential to cause tree and structural damage, plus power outages. 3. Dangerous storm surge is possible overnight 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 12/0300Z 37.1N 76.1W 45 KT 50 MPH 12H 12/1200Z 39.2N 71.2W 50 KT 60 MPH...POST-TROP/EXTRATROP 24H 13/0000Z 42.5N 61.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 36H 13/1200Z 45.4N 49.0W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 14/0000Z 47.1N 34.8W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 15/0000Z 47.6N 14.6W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 16/0000Z...DISSIPATED $$ Forecaster Berg
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Category:Transportation and Logistics