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BULLETIN
Tropical Depression Ida Advisory Number  23
NWS Weather Prediction Center College Park MD   AL092021
400 PM CDT Tue Aug 31 2021
 
...TROPICAL DEPRESSION IDA IS MOVING ACROSS THE TENNESSEE VALLEY...
...WIDESPREAD HEAVY RAIN AND AREAS OF POTENTIALLY LIFE THREATENING 
FLASH FLOODING ARE POSSIBLE BEGINNING WEDNESDAY ACROSS PORTIONS OF 
THE MID ATLANTIC AND SOUTHERN NEW ENGLAND...
 
 
SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
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LOCATION...35.5N 86.2W
ABOUT 65 MI...105 KM NNE OF HUNTSVILLE ALABAMA
ABOUT 125 MI...200 KM W OF KNOXVILLE TENNESSEE
MAXIMUM SUSTAINED WINDS...25 MPH...35 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES
 
 
WATCHES AND WARNINGS
--------------------
Flood and Flash Flood Watches extend from the Tennessee and Ohio
Valleys across the central and southern Appalachians, into the
Mid-Atlantic and southern New England.
 
 
DISCUSSION AND OUTLOOK
----------------------
At 400 PM CDT (2100 UTC), the center of Tropical Depression Ida was
located near latitude 35.5 North, longitude 86.2 West. The
depression is moving toward the northeast near 17 mph (28 km/h) and
this motion is expected to gradually accelerate through Wednesday. 
 
Maximum sustained winds are near 25 mph (35 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours as Ida 
becomes extratropical and moves offshore by early Thursday.
 
The estimated minimum central pressure is 999 mb (29.50 inches).
 
 
HAZARDS AFFECTING LAND
----------------------
RAINFALL: Tropical Depression Ida will produce the following
rainfall totals:
 
Portions of the Southeast, including the western Florida panhandle,
eastern and northern Alabama, and northern Georgia: An additional 1
to 3 inches through Wednesday morning.
 
Middle Tennessee Valley, Ohio Valley, Central and Southern
Appalachians: 3 to 6 inches with isolated higher amounts through
Wednesday morning.
 
Mid Atlantic to Southern New England: 3 to 8 inches with isolated
higher amounts, Wednesday into Thursday.
 
Considerable flash flooding is possible from the Middle Tennessee
Valley, Ohio Valley, Central and Southern Appalachians.
 
Significant and life-threatening flash flooding is possible from the
Mid-Atlantic into southern New England, especially across highly
urbanized metropolitan areas and areas of steep terrain. Widespread
moderate and major river flooding impacts are forecast from northern
West Virginia and western Maryland into southern Pennsylvania and
New Jersey, particularly in the Monongahela, Potomac, Susquehanna,
Delaware, and lower Hudson river basins.
 
Widespread minor to isolated major river flooding is occurring or
forecast from the Lower Mississippi Valley into far western Alabama.
Rivers will remain elevated into next week.
 
For the latest rainfall reports and wind gusts associated with
Tropical Depression Ida, see the companion storm summary at
WBCSCCNS4 with the WMO header of ACUS44 KWBC or at the following
link:
 
www.wpc.ncep.noaa.gov/discussions/nfdscc4.html
 
TORNADOES: The threat for an isolated tornado will continue this
evening across portions of the Southeast, shifting towards portions
of the Mid Atlantic overnight. On Wednesday, several tornadoes are
probable across portions of the Mid Atlantic, mainly during the
afternoon and evening hours.
 
 
NEXT ADVISORY
-------------
Next complete advisory at 1000 PM CDT.
 
$$
Forecaster Churchill
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  31/2100Z 35.5N  86.2W   20 KT  25 MPH...INLAND
 12H  01/0600Z 37.0N  83.5W   20 KT  25 MPH...INLAND
 24H  01/1800Z 39.0N  79.0W   25 KT  30 MPH...INLAND
 36H  02/0600Z 40.4N  73.6W   35 KT  40 MPH...POST-TROP/EXTRATROP
 48H  02/1800Z 43.8N  67.4W   35 KT  40 MPH...POST-TROP/EXTRATROP
 
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