578
FXUS01 KWBC 181845
PMDSPD
Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
144 PM EST Tue Nov 18 2025

Valid 00Z Wed Nov 19 2025 - 00Z Fri Nov 21 2025

...Scattered thunderstorms with intense rainfall across the Lower
Colorado Valley today will linger but reduce in coverage tomorrow
(Wednesday)..

...Risk of showers and thunderstorms capable of scattered
incidents of flash flooding expands into the Southern Plains
Wednesday night through Friday...

...Well above average warmth for the South from the Plains today
through the Southeast Thursday with a few records possible...

...Moderate to heavy snow over parts of the southern Utah
Mountains and Sierra Nevada Mountains...

The slow moving closed low affecting southern California will
persist with very slow drift eastward finally lifting out of
Northwest Mexico on Thursday into Friday.  This low and associated
cold front have been tapping increased moisture off the
sub-tropical East Pacific drawing it northward into Arizona and
southern Nevada helping to fuel thunderstorms capable of inducing
intense rain-rates and localized flash flooding conditions.  As
such, a Slight Risk of Excessive Rainfall (level 2 of 4) and Flood
Watch remain in place for the remainder of today into tomorrow
morning for much of western of Arizona and adjacent Nevada/E
California.  Colder air at elevation across the Sierra Nevada and
southern Utah Ranges will also tap the increased moisture and
produce moderate to heavy snow fall for the remainder of the
evening into the overnight period.  Additional 3-6" totals are
probable with isolated higher amounts in the highest peaks of the
Sierra Nevada Range.   The stubborn low will continue to slog
eastward but with weakening winds and moisture availability, the
overall coverage for excessive rainfall will reduce toward a more
isolated nature, though flash flooding remains possible, a
Marginal Risk (1 of 4) covers much of southern Arizona into
Southwest NM.

By Thursday, another shot of strong Pacific energy will near the
Northwest, though much will lift northward into British Columbia,
the southern edge of the cold front and some upper-level jet
energy will dig southward helping to kick the stubborn wave into
toward the Southern Plains, while the return of southerly low
level flow will bring back another shot of light rain and snow for
Oregon/Northern California before developing another surface low
rounding SW California for additional moderate rainfall risk on
late Thursday to Friday morning...another Marginal Risk will be in
place for flooding potential given high runoff due to saturated
soils.

Elsewhere, a weak surface low through the Mid-Mississippi River
Valley will slide eastward into the Ohio Valley today with the
potential for isolated severe weather, including hail, winds and
an isolated possible tornado.  The Storm Prediction Center (SPC)
has highlighted portions of S IL, S IND and W KY/NW TN with a
Marginal Risk (level 1 of 5).  By early morning the lingering
showers will cross the Central Appalachians and Mid-Atlantic
providing some rainfall before clearing by evening Thursday.

In the wake of the weak wave and due to the approach of the
Southwest closed low, strong southerly winds will bring enhanced
moisture and warmer temperatures off the Gulf of Mexico.
Temperatures will reach of the upper 70s and 80s across the
Southern Plains into the lower Mississippi Valley today with a
scattering of potential record high and overnight warm lows.  The
warmth will expand eastward into the Deep South Thursday and
toward the Southeast by Thursday with similar 10-20 degree above
normal temps and scattered potential records.

However, the high moisture/temperatures will aid thunderstorm
activity on Thursday into Friday across the Southern Plains.  The
slow moving upper-level wave will also allow for slower moving
thunderstorms capable of intense rainfall rates and scattered
incidents of flash flooding across portions of Texas.  Wednesday,
a Marginal Risk of Excessive Rainfall will be in place from the
Pecos River Valley through northern Texas/Southern Oklahoma; by
Thursday this expands to a Slight Risk to reach SW Missouri,
Arkansas back through the Hill Country of Texas.  A Flood Watch is
already in place for portions of the Hill Country and Edwards
Plateau in Texas.

Gallina


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

$$