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| #985801 (Received by flhurricane at: 2:23 PM 11.Oct.2019) TCDAT4 Subtropical Storm Melissa Discussion Number 1 NWS National Hurricane Center Miami FL AL142019 1100 AM AST Fri Oct 11 2019 Convection increased near the center of the nor'easter centered southeast of New England overnight. First-light visible satellite imagery briefly showed an eye-like feature before the convection around the immediate center began to weaken. However, a large convective band still persists over the northern semicircle, and this structure indicated the system has transitioned to a subtropical cyclone. The latest Hebert-Poteat classification from TAFB indicates an initial intensity of 55 kt, and this is also supported by an earlier scatterometer overpass showing a large area of winds near 50 kt in the northwest quadrant. Melissa is currently located underneath an upper-level trough, resulting in a light shear environment. This trough will begin to lift northeastward later today, and strong upper-level westerlies should begin to affect the storm by tonight. This pattern is expected to cause a weakening trend, and Melissa is forecast to become post-tropical by Saturday night. The post-tropical cyclone is then expected to be absorbed by an approaching front in 3 to 4 days. Melissa is currently embedded in weak steering flow under the upper- level trough, and little net motion is expected today. Later tonight, an approaching mid-latitude trough currently crossing the upper Midwest will begin to force an east-northeastward motion at a faster forward speed. This motion will continue until the cyclone is absorbed by the cold front. The NHC track forecast is closest to the ECMWF ensemble mean. Ongoing hazards from wind and coastal flooding will continue be covered by non-tropical products from local National Weather Service forecast offices. Gale-force winds that extend well northeastward of Melissa into the central Atlantic that are not included in the wind radii, since they are associated with a frontal boundary. Key Messages: 1. While the nor'easter centered southeast of New England has become Subtropical Storm Melissa, the expected magnitude of wind and coastal flooding impacts along portions of the U.S. east coast from the mid-Atlantic states to southeastern New England has not changed. For information on these hazards, see products issued by local National Weather Service forecast offices at weather.gov. 2. Melissa is expected to gradually weaken and begin moving away from the U.S. east coast by tonight, resulting in a gradual decrease in wind and coastal flooding impacts. FORECAST POSITIONS AND MAX WINDS INIT 11/1500Z 38.5N 69.6W 55 KT 65 MPH 12H 12/0000Z 38.2N 69.3W 45 KT 50 MPH 24H 12/1200Z 38.4N 67.7W 35 KT 40 MPH 36H 13/0000Z 39.0N 65.1W 30 KT 35 MPH...POST-TROPICAL 48H 13/1200Z 39.9N 61.0W 30 KT 35 MPH...POST-TROPICAL 72H 14/1200Z 41.3N 52.6W 30 KT 35 MPH...POST-TROPICAL 96H 15/1200Z...ABSORBED $$ Forecaster Latto |
