Tropical Depression Ida Forecast Discussion Number 19
ActuCyclone
30 août 2021
000 WTNT44 KNHC 302037 TCDAT4 Tropical Depression Ida Discussion Number 19 NWS National Hurricane Center Miami FL AL092021 400 PM CDT Mon Aug 30 2021 Ida has continued to weaken while moving farther inland over west-central Mississippi this afternoon. Recent observations indicate that the stronger winds seen this morning along the northern Gulf coast have now dropped below tropical storm strength, and Ida has become a tropical depression. Additional weakening should occur while Ida moves over northeastern Mississippi and the Tennessee Valley during the next 12 to 24 hours. Ida is forecast to become an extratropical cyclone over the eastern United States by late Wednesday, and it is likely to be absorbed within a frontal boundary over the western Atlantic by the end of the forecast period. Ida has turned northeastward and is now moving 020/8 kt. A mid- to upper-level trough approaching Ida from the west should cause the cyclone to move faster toward the northeast over the next couple of days. The latest runs of the dynamical models are in a bit better agreement regarding the forward speed of the Ida as it moves across the eastern U.S., and the NHC track forecast is again near the middle of the guidance envelope. Although Ida's winds have decreased, the threat of heavy rainfall and flooding will continue to spread inland over portions of the Tennessee and Ohio Valleys, the Central and Southern Appalachians and the Mid-Atlantic through Wednesday. This is the last advisory issued by the National Hurricane Center on Ida. Future information on this system can be found in Public Advisories issued by the Weather Prediction Center beginning at 10 PM CDT, under AWIPS header TCPAT4, WMO header WTNT34 KWNH, and on the web at http://www.wpc.ncep.noaa.gov. Key Messages: 1. Ida will continue to produce heavy rainfall tonight through Tuesday morning across portions of southeast Louisiana, Mississippi, and western Alabama, resulting in considerable flash and urban flooding and significant river flooding impacts. Rivers in the Lower Mississippi Valley will remain elevated into next week. As Ida moves inland, additional considerable flooding impacts are likely across portions of the Tennessee Valley, the Ohio Valley, and particularly in the Central and Southern Appalachians into the Mid-Atlantic through Wednesday. 2. In areas that experienced damage and power loss, individuals should use extreme caution during the recovery phase. Post-storm fatalities and injuries often result from heart attacks, heat exhaustion, accidents related to clean up and recovery, and carbon monoxide poisoning from improper generator use. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 32.6N 90.3W 30 KT 35 MPH...INLAND 12H 31/0600Z 33.6N 89.3W 25 KT 30 MPH...INLAND 24H 31/1800Z 34.8N 87.2W 25 KT 30 MPH...INLAND 36H 01/0600Z 36.3N 84.3W 20 KT 25 MPH...INLAND 48H 01/1800Z 38.0N 80.7W 20 KT 25 MPH...POST-TROP/INLAND 60H 02/0600Z 39.0N 77.0W 25 KT 30 MPH...POST-TROP/EXTRATROP 72H 02/1800Z 39.5N 74.2W 30 KT 35 MPH...POST-TROP/EXTRATROP 96H 03/1800Z 41.0N 67.9W 30 KT 35 MPH...POST-TROP/EXTRATROP 120H 04/1800Z...DISSIPATED $$ Forecaster Brown