404
AGUS74 KWCO 011956
HMDNWC

National Hydrologic Discussion - EXPERIMENTAL
NWS National Water Center - Tuscaloosa AL
300 PM CDT THU OCT 1 2026

...Considerable flash and urban flooding impacts possible across the
Central Plains into the Middle Mississippi Valley... Considerable flash
flooding possible across parts of the Marianas... Locally considerable flash,
urban, and river flooding possible across the Southern Plains... Flooding
possible on the Gulf Coast this weekend into next week...

.Central Plains into the Middle Mississippi Valley...
Considerable flash and urban flooding is possible across much of IA and
eastern NE into far northeast KS/northwest MO. Widespread rainfall totals
of 2 - 5", locally up to 7" have already fallen over the region, leading to
numerous flooding reports and observed/forecast minor to moderate river
flooding and making the area hydrologically sensitive to any additional
rainfall. Current forecasts have the rainfall shifting out of NE/IA and
into KS/MO, where an additional 1 - 2"+ of rainfall is possible.
Streamflows are already running above or near all-time highs for the day of
year, and runoff from this additional rainfall will runoff into already
swollen streams and rivers and exacerbate ongoing flooding. The National
Water Model (NWM) short-range forecast (SRF) has consistently pinging the
same axis of potential flooding from west of Wichita, KS through Topeka
into northern MO, including the Kansas City Metropolitan Area. Rapid-onset
flooding (ROF) probabilities are mostly in the 25 - 75% range and signals
from the highflow magnitude forecast service show widespread exceedance of
10 - 2% annual exceedance probability (AEP) thresholds along that same
axis. These signals support the potential for considerable flash, urban,
and small stream flooding through the region through this afternoon and
into the evening.

.Southern Plains...
Locally considerable flash, urban, and river flooding is possible due to
heavy rainfall through Friday. Given the narrow strip of rainfall from
yesterday, soil moistures range from on the drier side in much of West
Texas, to saturated from the Big Bend of Texas into south-central Oklahoma,
to very dry in southern and eastern Texas into Arkansas. Though the drier
soils may mitigate impacts briefly, complex terrain and training rainfall
will quickly overwhelm infiltration capacity, resulting in rapid runoff and
flash flooding.  All three forcings of the  NWM (HRRR, GFS, and NBM)
continue to show strong responses across the region suggesting some
increased confidence with rapid stream responses along with flash and urban
flooding impacts, some of which may be locally considerable. However, there
remains some uncertainty in the exact placement of greatest flooding
impacts. River flooding will also be a concern for this event, with
isolated moderate and major river flooding currently forecast or observed
over portions of central Texas. River ensembles also suggest the potential
for additional flooding within the region, but that will depend on where
rain falls tonight and tomorrow.  Larger rivers will see delayed responses
later this week as water routes downstream.

.Gulf Coast...
Multiple days of heavy rainfall are forecast along coastal Louisiana,
Mississippi, Alabama, and the Florida Panhandle beginning this weekend and
persisting into next week. The heaviest QPF is expected to remain off the
coast, but the 7-day totals are forecast to eclipse 7", bringing potential
for isolated flash and urban flooding. Saturday night into Sunday appears
to have the highest flood potential out of any of the days this coming
week. Dry antecedent conditions will help alleviate widespread flooding
concerns, but localized heavy rainfall rates could lead to flooding issues,
especially in urban areas. Both the NBM and GFS-forced versions of the NWM
are currently only signaling small pockets of AEPs in the 50 - 10% range,
supporting the potential for isolated flooding impacts.


.Northern Marianas...
Tropical Storm Choi-wan will bring heavy rain to the islands resulting in
flash flooding to the islands through this weekend. Considerable flooding
is possible across Saipan and Tinian.

//GKendrick/Bliss

Additional National Water Center products are available at
www.weather.gov/owp/operations