000 WTNT44 KNHC 170831 TCDAT4 Tropical Depression Sally Discussion Number 25 NWS National Hurricane Center Miami FL AL192020 400 AM CDT Thu Sep 17 2020 Although the overall convective cloud and rain shield in satellite and radar imagery continues to erode, Tropical Depression Sally is still producing significant rainfall across east-central Alabama and west-central and central Georgia. Surface observations and Doppler radar data indicate that Sally has weakened to a 25-kt depression over southeastern Alabama. Sally will continue to weaken, and fairly rapidly at that, due to increasing friction and loss of convection owing to very hostile westerly to southwesterly vertical wind shear in excess of 40 kt. Sally will likely degenerate into a remnant low pressure system by tonight or early Friday, and merge with a frontal system over North Carolina by Friday evening. Sally is moving northeastward or 055/10 kt. A northeastward to east-northeastward motion will continue for the next 36 hours or so as the cyclone moves ahead of a broad deep-layer trough over the northeastern United States. The official track forecast is down the middle of the tightly packed NHC model guidance suite, and lies close to the previous advisory track and the consensus model HCCA. This is the last NHC advisory on Sally. Future information on this system, including the rainfall threat, can be found in Public Advisories issued by the Weather Prediction Center beginning at 10 AM CDT, under AWIPS header TCPAT3, WMO header WTNT34 KWNH, and on the web at http://www.wpc.ncep.noaa.gov KEY MESSAGES: 1. Widespread flooding is expected from central Georgia through southeastern Virginia. Along the central Gulf Coast, most widespread moderate to major river flooding from the historic rainfall event will crest by the weekend, but rivers will remain elevated well into next week. FORECAST POSITIONS AND MAX WINDS INIT 17/0900Z 31.8N 85.7W 25 KT 30 MPH...INLAND 12H 17/1800Z 32.8N 84.2W 25 KT 30 MPH...INLAND 24H 18/0600Z 34.0N 81.3W 20 KT 25 MPH...POST-TROP/REMNT LOW 36H 18/1800Z 35.1N 78.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 48H 19/0600Z...MERGED WITH FRONTAL SYSTEM $$ Forecaster Stewart