Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
323 PM EDT Mon Sep 28 2026

Valid 00Z Tue Sep 29 2026 - 00Z Thu Oct 01 2026

...Potentially life-threatening flash flooding expected from the Southwest
into the southern High Plains into early Wednesday...

...Significant flash flooding threat shifts into north-central Texas
Wednesday, with heavy rain and river flooding concerns spreading into the
central Plains and Upper Midwest...

...Dangerous heat continues in South Texas, and much of the East turns
unseasonably warm...

A multi-day and potentially dangerous flash flood event is getting
underway across the Southwest as a strong upper-level low moves inland
from California, crossing Arizona on Tuesday before reaching New Mexico by
Wednesday. Ahead of this system, tropical moisture from the remnants of
Hurricane Polo, which is forecast to move across Baja California tonight
and into northwest Mexico on Tuesday, will be drawn northeastward into the
region. Moisture levels this high are rare this late in the season.
Combined with robust lift from the upper low, they will support torrential
rainfall rates and repeated rounds of storms over the same areas. Moderate
Risks of excessive rainfall (level 3 of 4) are in effect from Arizona and
southern Utah into New Mexico, far west Texas, and the southern High
Plains, and Flash Flood Watches cover much of the region. Numerous
instances of flash flooding are expected, and some could become
life-threatening, particularly Tuesday into Tuesday night when the
heaviest rain is likely to fall after dark. Burn scars, urban areas, and
normally dry washes will be especially vulnerable. A few severe
thunderstorms with damaging winds are also possible Tuesday across the
southern High Plains. Temperatures across the Desert Southwest will run
well below average under the clouds and rain.

By Wednesday, the moisture plume will surge northeastward along a
slow-moving front from the southern High Plains to the Upper Midwest.
North-central Texas is a particular concern. repeated rounds of intense
storms Wednesday night could produce significant flash flooding there, and
another Moderate Risk is in effect. Farther north, a soaking rain from the
central Plains into Iowa, southern Minnesota, and Wisconsin could lead to
scattered flash flooding and rising rivers. Behind the system, a cold
front dropping south from Canada will bring noticeably cooler air into the
northern Plains by Wednesday.

Farther east, the weakening nor'easter will exit into the Canadian
Maritimes by Wednesday. High tides will still bring coastal flooding at
times to part of the Southwest and Mid-Atlantic coasts. High pressure
building in behind the storm will bring dry weather and a warming trend,
with highs near 90 degrees across the Southeast by midweek, while heat
indices in South Texas exceed 105 degrees. Out West, a Pacific front will
bring rain to the Pacific Northwest on Tuesday, and offshore winds will
begin a significant warning trend across California.


Eovino


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx...

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