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Tropical Storm Ida Discussion Number  18
NWS National Hurricane Center Miami FL       AL092021
1000 AM CDT Mon Aug 30 2021
 
The center of Ida has moved farther inland over western Mississippi 
this morning and NWS Doppler radar velocities and surface 
observations indicate that the tropical cyclone's winds have 
continued to decrease.  The strongest winds are located in a band 
well southeast of the center along the coasts of Mississippi and 
Alabama where recent surface reports indicate 30-35 kt winds are 
still occurring. Therefore, the initial intensity is set at 35 kt.  
As Ida's circulation moves farther inland, additional weakening is 
expected and Ida is expected to become a tropical depression this 
afternoon.  Continued weakening should occur while Ida moves over 
the Tennessee Valley on Tuesday, and the system is forecast to 
become extratropical over the eastern United States by late 
Wednesday. The global models indicate that the post-tropical cyclone 
will be absorbed by a frontal zone over the western Atlantic by the 
end of the forecast period.
 
Ida is moving moving just east of due north or 010/8 kt. A
north-northeastward turn should occur later today, followed by a
faster northeastward motion tonight and Tuesday as a mid- to
upper-level trough approaches the cyclone from the west. The
dynamical model guidance remains tightly clustered with very little
cross-track spread, although there remains some speed or along-track 
spread in the guidance. The NHC forecast is near the HCCA and TCVA
consensus models.
 
Key Messages:
 
1. Dangerous storm surge inundation will continue into this 
afternoon along portions of the coasts of Mississippi and Alabama. 
 
2. Tropical storm force winds, especially in gusts, will continue
over portions of southeastern Louisiana, southern Mississippi and
southern Alabama this afternoon.
 
3. 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.
 
4. 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  30/1500Z 31.9N  90.7W   35 KT  40 MPH...INLAND
 12H  31/0000Z 33.1N  90.1W   30 KT  35 MPH...INLAND
 24H  31/1200Z 34.5N  88.4W   25 KT  30 MPH...INLAND
 36H  01/0000Z 35.8N  85.9W   20 KT  25 MPH...INLAND
 48H  01/1200Z 37.5N  82.5W   20 KT  25 MPH...POST-TROP/INLAND
 60H  02/0000Z 38.9N  78.7W   20 KT  25 MPH...POST-TROP/EXTRATROP
 72H  02/1200Z 39.5N  75.7W   25 KT  30 MPH...POST-TROP/EXTRATROP
 96H  03/1200Z 40.5N  70.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
120H  04/1200Z...DISSIPATED
 
$$
Forecaster Brown
 
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