394
AGUS74 KWCO 211522
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT FRI MAR 21 2025

.Synopsis...
Rainfall and snow melt for the Northeast and Pacific Northwest... Renewed
flooding possible for the Lower Ohio Valley and Lower Mississippi and
Tennessee Valleys... Routed flow resulting in continued rises across the
Atlantic Coastal Plain...Flash and urban flooding possible in American
Samoa...

.Discussion...

.Northeast...
Recent rainfall and snow melt has led to elevated rivers across the region
and ice jam flooding impacts remain a concern along rivers with ice
remaining, especially in northern ME. Additional rainfall and snow melt is
expected on day 4 (Mon), but any subsequent flooding threats remain
uncertain at this time.

.Pacific Northwest...
Periods of rainfall and low-to-mid elevation snow melt throughout the next
week will continue the isolated river flooding threat across the region,
especially across OR, with isolated minor river flooding possible by early
next week.

.Lower Ohio Valley...
Additional rainfall is expected on day 3 (Sun) across portions of the Lower
Ohio Valley. Kentucky and southern IN could see new and renewed river rises
(National Water Model (NWM), MMEFS, HEFS), especially considering wet soils
(65 - 75%, 0 - 10cm RSM, NASA SPoRT) and much above normal streamflows
(USGS). However, details regarding the subsequent flooding threats remain
uncertain at this time.

.Lower Mississippi and Tennessee Valleys...
Widespread rainfall (0.5 - 1.5") is expected on day 3 (Sun) from LA through
MS/northern AL into central TN, where soils remain wet (55 - 75%, 0 - 10 cm
RSM, NASA SPoRT) and streamflows remain elevated (USGS) from recent
rainfall. Details regarding the subsequent flooding threats including the
potential magnitude of localized responses remain uncertain at this time,
however, the NWM continues to show some consistency in signaling potential
for fairly widespread river rises on smaller rivers throughout the
aforementioned region.

.Atlantic Coastal Plain...
Isolated minor river flooding throughout the Southeast Atlantic Coastal
Plain is either ongoing or forecast to occur by early-to-mid next week as
routed flow makes its way through the river systems from recent rainfall.

American Samoa...
Flash and urban flooding is possible through day 1 (Fri) (local time).
Landslides will also be possible in areas of steep terrain.

//TMK





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