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Tropical Depression Eleven Forecast Discussion Number 2
2020-08-12 04:33:49| National Hurricane Center (Atlantic)
Issued at 1100 PM AST Tue Aug 11 2020 913 WTNT41 KNHC 120233 TCDAT1 Tropical Depression Eleven Discussion Number 2 NWS National Hurricane Center Miami FL AL112020 1100 PM AST Tue Aug 11 2020 After weakening in the early evening hours, deep convection has returned to the western semicircle of the tropical cyclone. While this is quite a strong burst, it appears that the convective pattern is indicative of the shear it is encountering, rather than any strengthening. This is confirmed by ASCAT-B data from a few hours ago, which supported maintaining an initial wind speed of 30 kt. By this time tomorrow, the depression is forecast to become a tropical storm due to decreasing vertical wind shear, and this environmental change should also keep some of the surrounding mid-level dry air from mixing near the center. Gradually warming SSTs and relatively low shear conditions suggest further intensification through about 2-3 days. Thereafter, increasing southwesterly shear while the small cyclone moves through fairly dry air aloft is forecast to cause a weakening trend, and it wouldn't be surprising if the cyclone even degenerates to a trough by day 5 as it traverses the hostile environment. The new NHC wind speed prediction is near but slightly higher than the previous advisory through 60h, similar afterwards, and lies near the NOAA corrected-consensus mean. The depression continues moving westward, or 280/12 kt, to the south of a large mid-tropospheric high centered over the central Atlantic. A break developing in the ridge should steer the depression more west-northwestward from 36 hours until the end of the forecast period. For a second advisory, the track models are in remarkably good agreement, and the forecast is near or northeast of the model consensus. The HWRF solution that takes the cyclone near the Leeward Islands is considering less likely at this time, hence the official forecast is shaded toward the other model solutions. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 12.0N 41.5W 30 KT 35 MPH 12H 12/1200Z 12.3N 43.4W 30 KT 35 MPH 24H 13/0000Z 12.8N 45.9W 35 KT 40 MPH 36H 13/1200Z 13.5N 48.3W 40 KT 45 MPH 48H 14/0000Z 14.5N 50.8W 45 KT 50 MPH 60H 14/1200Z 15.7N 53.3W 50 KT 60 MPH 72H 15/0000Z 17.0N 55.7W 45 KT 50 MPH 96H 16/0000Z 19.5N 60.5W 40 KT 45 MPH 120H 17/0000Z 22.0N 65.0W 35 KT 40 MPH $$ Forecaster Blake
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