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Subtropical Storm Melissa Forecast Discussion Number 4
2019-10-12 10:31:19| National Hurricane Center (Atlantic)
Issued at 500 AM AST Sat Oct 12 2019 000 WTNT44 KNHC 120831 TCDAT4 Subtropical Storm Melissa Discussion Number 4 NWS National Hurricane Center Miami FL AL142019 500 AM AST Sat Oct 12 2019 Deep convection has increased a little near the center of Melissa during the past few hours, likely because it has moved over the warmer waters of the Gulf Stream current. However, convection is quite limited elsewhere. An ASCAT-B pass from several hours ago showed maximum winds of about 40 kt in the northwestern quadrant. However, this pass did not completely capture the entire circulation, so the initial intensity is held at 45 kt given that stronger winds could exist in the regions not sampled. This intensity estimate is also in fair agreement with the latest satellite estimates as well. Melissa is expected to resume weakening later today due to a combination of an increase in westerly wind shear and intrusions of dry air. The cyclone will likely degenerate to a remnant low in about 24 hours when the system is forecast to be over SSTs of 23 to 24 C. The remnant low is expected to linger for at least a couple of days before it is absorbed within a frontal zone over the north Atlantic. The NHC intensity forecast is in best agreement with the GFS, UKMET, and ECMWF global models. The subtropical storm has turned northeastward during the last several hours, with the initial motion estimated to be 055/6 kt. The weakening system is expected to become more embedded in the mid-latitude westerlies during the next few days, and as a result, a turn to the east-northeast with an increase in forward speed is forecast, taking the cyclone away from the Mid-Atlantic and northeast U.S. coastline. The NHC track forecast is adjusted a little to the north of the previous one to be in better agreement with the latest model runs. Ongoing hazards from wind and coastal flooding will continue to be covered by non-tropical products from local National Weather Service forecast offices. Gale-force winds that extend from Nova Scotia eastward over the Atlantic are not included in the wind radii, since they are associated with a frontal boundary. Key Messages: 1. Melissa is expected to slowly weaken and move away from the U.S. east coast today, resulting in a gradual decrease in wind and coastal flooding impacts. 2. Minor to moderate coastal flooding is still expected along portions of the U.S. Mid-Atlantic and southeastern New England coasts around times of high tide today. For more information, see products issued by local National Weather Service forecast offices at weather.gov. FORECAST POSITIONS AND MAX WINDS INIT 12/0900Z 38.1N 68.2W 45 KT 50 MPH 12H 12/1800Z 38.4N 66.7W 40 KT 45 MPH 24H 13/0600Z 39.0N 63.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 36H 13/1800Z 39.6N 60.4W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 14/0600Z 40.3N 56.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 15/0600Z 41.6N 47.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 16/0600Z...ABSORBED WITHIN A FRONTAL ZONE $$ Forecaster Cangialosi
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