532
AGUS74 KWCO 071531
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT MON APR 7 2025

.Synopsis...
Widespread river flooding and ongoing flooding impacts continue across the
Southern Plains and Mississippi, Tennessee, and Ohio Valleys... Flooding
possible in the Southeast into the Mid-Atlantic...

.Discussion...

.Southern Plains and Mississippi, Tennessee, and Ohio Valleys...
Historically high rainfall has caused catastrophic flooding across the
region, leading to widespread impacts that will continue to persist
throughout the week. Additionally, isolated river flooding exceeding record
levels is forecast in the Lower OH Valley, along with exceedingly rare,
widespread major river flooding occurring across the Lower OH Valley
through the Lower MS Valley. Widespread minor to moderate river flooding is
also extending from the Middle OH Valley to northeast TX. Flooding on most
rivers will continue over the week, with some smaller streams and rivers
receding over the next few days. Significant rainfall has ended and rivers
running high will be able to recede unimpeded.

.Southeast into the Mid-Atlantic...
Heavy rainfall bringing the chance for isolated flash, urban and small
stream flooding will be possible through today in portions of southeast AL
and central GA. This rainfall will continue east into SC and NC as the day
progresses. Infiltration capacity has decreased in portions of the
Southeast. Soils are wet suggesting there are very little mitigating
factors remaining to impede runoff into already elevated streams and creeks
and will likely become overwhelmed (70 - 95%, NWM Soil Moisture Analysis).
Minor to isolated moderate river flooding is currently forecast in AL and
GA.

The HRRR-forced National Water Model (NWM) Short Range Forecast (SRF) has
been signaling the potential for rapid-onset flooding across southeast AL,
central GA, and northern SC with probabilities generally between 25 - 50%.
Corresponding annual exceedance probabilities, per the SRF High Flow
Magnitude, remain mostly at or above 50% overall, except in areas
surrounding Columbus and Macon, GA, where higher magnitude/lower AEPs
(between 10% and 2%) on smaller streams suggest the possibility of
significant hydrologic responses.

//Kirkpatrick/Leisure



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