787
AGUS74 KWCO 291530
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
1015 AM CDT FRI AUG 29 2025

.Synopsis...
Flash and urban flooding is possible across East Texas into the
Southeast... Isolated flash and urban flooding expected to continue across
the Southwest into the Southern Plains... River rises/potential significant
flooding in Alaska...

.East Texas into the Southeast...
Forecast heavy rainfall will continue into this weekend across portions of
east TX, LA, MS, and AL which has caused instances of isolated flash and
urban flooding. Portions of this area have seen 1 - 5"+ over the past 24
hours (MRMS). Soils (0 - 10cm RSM, NASA SPoRT) and streams (USGS) are
generally less conducive to hydrologic impacts as drier conditions and
below normal flows prevail across much of the region. However, rainfall
over the past 24 hours have primed the surface soils allowing for efficient
runoff to occur. High rainfall rates and training thunderstorms remain the
primary concern for generating flooding impacts. River ensemble guidance
continues to suggest isolated rises to minor should not be ruled out, but
will be highly dependent on the training rainfall mentioned above. The
National Water Model Short Range Forecast is signaling rapid-onset flooding
probabilities of up to 50% for basins in northern LA and far southwestern
MS with peak flows occurring over the next 6 hours. Scattered thunderstorms
remain a possibility for this region through the weekend but are unlikely
to generate flooding concerns.

.Southwest into the Southern Plains...
Monsoonal moisture continues to threaten the area with instances of
isolated flash and urban flooding, particularly over recently burned areas.
Rainfall forecasts for the next 3 days suggest the majority of the forecast
QPF will be in western/central TX and OK Panhandles and gradually sinking
south before another potential push into NM by late next week. Confidence
in the exact placement and magnitude is low, late in the period, due to the
timing. The rainfall totals are broadly 1 - 3" with some embedded higher
totals, which combined with recently burned areas may cause debris flows
and subsequent flash flooding.

.Alaska...
An atmospheric river will continue to bring heavy rainfall causing
widespread rapid rises on rivers and streams along with flooding in basins
in central and southern AK. Several inches of rainfall combined with basins
that are also experiencing glacial runoff are vulnerable to significant
flooding impacts. While lingering flooding may continue into next week, the
minor and moderate flood forecasts are expected to peak by this weekend.

//JAC

$$