698
FOUS30 KWBC 300805
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
405 AM EDT Sat Aug 30 2025

Day 1
Valid 12Z Sat Aug 30 2025 - 12Z Sun Aug 31 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM EASTERN NEW
MEXICO INTO WEST TEXAS AND ACROSS THE PLAINS...

...Rockies into the Plains...

Increased troughing and embedded shortwave energy is expected
during this period as the upper level ridging breaks down. This
may result in widespread convection to develop and spread out
across the Plains. An axis of high QPF values is expected to set up
from far eastern New Mexico east towards the Dallas/Fort Worth
area, which will be the area with the highest potential for flash
flooding, especially near steep terrain and burn scars. This
pattern supports terrain driven convection over New Mexico growing
upscale as it moves eastward into western Texas resulting in an
isolated to scattered flash flood threat.The Slight Risk area was
maintained for this part of the region. Elsewhere, the broad
Marginal was maintained across much of the Plains and for portions
of the Gulf Coast and Southeast. There was an uptick in QPF amounts
and coverage across portions of eastern Texas which warranted an
eastern nudge of the Marginal Risk.

The Slight Risk area across the Plains was expanded eastward into
eastern Kansas and far northern Oklahoma, which was supported by
hi- res CAM QPF, high HREF probabilities for rain rates exceeding 1
inch per hour and 2 inches per 6 hours, and moderate HREF
probabilities for 24 hour QPF exceeding 5-year ARIs. The latest
guidance depicted a southern shift and reduction in threat of
excessive rainfall for parts of South Dakota and northern Nebraska,
therefore the northern bounds of the Slight Risk was trimmed down
to eastern Nebraska. Within this Slight Risk area, the high end
potential is expected to focus over eastern Nebraska, where this
will likely become more of a long duration event with high rain
rates in individual storms.

Campbell/Dolan


Day 2
Valid 12Z Sun Aug 31 2025 - 12Z Mon Sep 01 2025


...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM SOUTHERN NEW
MEXICO INTO WEST/CENTRAL TEXAS AND FOR EASTERN NEBRASKA...

Convection over eastern Nebraska and Kansas will likely see enough
instability and moisture to support high rain rates. Soils in this
region should also be saturated from heavy rain/storms expected on
Saturday, resulting in a heightened flash flood risk. The inherited
Slight Risk was expanded south and east to cover more of eastern
Kansas.

The Slight Risk area in Texas was also expanded to include more of
eastern Texas and far southeast Arizona. This was to account for
an increasing trend in QPF and the potential for repeat
thunderstorm activity over areas that will be saturated by storms.
The better focus for higher QPF will be for locations near or east
of the Hill Country across eastern Texas.

The broader Marginal Risk areas for the southern tier and portions
of the Central/Northern Plains continue to highlight the level
threat for excessive rainfall and flooding potential across the
region.

Campbell


Day 3
Valid 12Z Mon Sep 01 2025 - 12Z Tue Sep 02 2025

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL FOR THE SOUTHERN
TIER, PLAINS AND TENNESSEE VALLEY...

A surface front will continue to be draped across the southern
tier of the country providing a focus for the monsoonal moisture
and Gulf moisture. There will be some upper level support for
isolated convection therefore the Marginal Risk was maintained from
New Mexico and southeast Arizona across southern/central parts of
Texas and the Gulf Coast through the Florida Peninsula.

To the north, a frontal system and a shortwave or two aloft will
support storms with higher rain rates across the Mid-Mississippi
Valley and the Tennessee Valley to Southern Appalachians.
Maintained the Marginal Risk areas for the Tennessee Valley and for
the Plains.

Campbell


Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt