461
FXUS01 KWBC 210637
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
236 AM EDT Mon Sep 21 2026

Valid 12Z Mon Sep 21 2026 - 12Z Wed Sep 23 2026

...Excessive Rainfall risk for portions of the Appalachians and
Mid-Atlantic on Monday...

...Severe thunderstorm risk for portions of the Southeast into
central Appalachians on Monday...

...Excessive Rainfall risk for portions of New Mexico and southern
Plains through Tuesday...


An upper trough and surface frontal system will progress across
central U.S. towards the Ohio Valley/Mid-Atlantic and will
gradually drape across portions of the southern Plains into the
Southeast. This will bring periods of showers and thunderstorms
along the boundary. Multiple rounds of moderate to locally heavy
rain are expected to develop over portions of the Appalachians and
Mid-Atlantic on Monday, as elevated instability and moisture
interacts with the boundary and surface trough. This will lead to
excessive rainfall/flash flooding concerns over portions of the
Appalachians and severe thunderstorms concerns over portions of
the Appalachians into the Southeast. On Tuesday, additional
shortwave energy over the Ohio Valley/Mid-Atlantic will bring
additional showers and thunderstorms. Locally elevated instability
and organized convection may produce high rainfall rates, leading
to another day of excessive rainfall over portions of the Ohio
Valley and Mid-Atlantic, while severe thunderstorms continue for
portions of the Appalachians and Southeast.

Furthermore, a moist tropical airmass will continue over portions
of Florida, bringing daily showers and thunderstorms, especially
over southern Florida. Locally heavy downpours will bring flooding
concerns through Tuesday. Across the Southwest, Gulf and Pacific
moisture will funnel into portions of the southern Plains,
Southwest, and Four Corners bringing a increase in showers and
thunderstorms on Monday, with activity becoming more widespread on
Tuesday. The combination of deep moisture and instability may lead
to locally heavy rainfall and flash flooding across New Mexico and
portions of western Texas through Tuesday.

A gradual transition to cooler temperatures is expected across the
north-central and eastern U.S. behind the advancing frontal system
with highs in the 60s. The Southeast and southern Plains will
remain warmer and humid with highs in the 80s and 90s.


Oudit



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






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