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Tropical Depression Ida Advisory Number 24
NWS Weather Prediction Center College Park MD AL092021
1100 PM EDT Tue Aug 31 2021
...TROPICAL DEPRESSION IDA IS MOVING ACROSS MIDDLE TENNESSEE...
...WIDESPREAD HEAVY RAIN AND AREAS OF POTENTIALLY LIFE THREATENING
FLASH FLOODING ARE POSSIBLE BEGINNING WEDNESDAY ACROSS PORTIONS OF
THE MID ATLANTIC INTO SOUTHERN NEW YORK AND SOUTHERN NEW ENGLAND...
...REMNANTS OF IDA WILL ALSO BRING AN ENHANCED RISK FOR SEVERAL
TORNADOES ACROSS PARTS OF THE MID-ATLANTIC ON WEDNESDAY...
SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
ABOUT 160 MI...260 KM NE OF HUNTSVILLE ALABAMA
ABOUT 45 MI...70 KM NW OF KNOXVILLE TENNESSEE
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES
WATCHES AND WARNINGS
Flood and Flash Flood Watches extend across the eastern Tennessee
and Ohio Valleys, southern and central Appalachians, the
northern Mid-Atlantic region, and into southern New York
and southern New England.
A tornado watch is in effect until 3 am EDT Wednesday across
extreme north-central North Carolina into western and central
DISCUSSION AND OUTLOOK
At 1100 PM EDT (0300 UTC), the center of Tropical Depression Ida was
located near latitude 36.2 North, longitude 84.6 West. The
depression is moving toward the east-northeast near 20 mph (31 km/h)
and this motion is expected to gradually accelerate through
Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
Some strengthening is forecast during the next 48 hours as Ida
becomes extratropical and moves offshore on Thursday.
The estimated minimum central pressure is 1000 mb (29.53 inches).
HAZARDS AFFECTING LAND
RAINFALL: Tropical Depression Ida will produce the following
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
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
TORNADOES: The threat for an isolated tornado will continue
tonight across 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 complete advisory at 500 AM EDT.
FORECAST POSITIONS AND MAX WINDS
INIT 01/0300Z 36.2N 84.6W 25 KT 30 MPH...INLAND
12H 01/1200Z 37.5N 81.7W 25 KT 30 MPH...INLAND
24H 02/0000Z 39.6N 76.6W 30 KT 35 MPH...INLAND
36H 02/1200Z 42.1N 71.1W 35 KT 40 MPH...POST-TROP/EXTRATROP
48H 03/0000Z 44.7N 65.7W 35 KT 40 MPH...POST-TROP/EXTRATROP