202
FXUS01 KWBC 180842
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
440 AM EDT Sat Oct 18 2025

Valid 12Z Sat Oct 18 2025 - 12Z Mon Oct 20 2025

...Heavy rain and severe thunderstorms expected to impact portions
of the ArkLaTex, Mid-South, Ohio Valley, and Great Lakes later
today into Sunday, reaching the East Coast Sunday night...

...Turning colder and unsettled across the Pacific Northwest and
northern Rockies with coastal and valley rain along with mountain
snow and gusty winds...

An increasingly active weather pattern that signals the emergence
of La Nina is forecast for the U.S. through the weekend into early
next week.  A deepening upper trough and a cold air mass from
western Canada force their way eastward will clash with a cold
front across the mid-section of the country.  The vigorous
dynamics associated with this interaction is forecast to produce a
rapidly intensifying low pressure system to track from the Midwest
tonight and then through the Great Lakes Sunday morning.  A potent
cold front trailing south from the cyclone center will be preceded
by an outbreak of severe weather across much of the mid to lower
Mississippi Valley from later today through tonight per the Storm
Prediction Center.  The main hazards to watch for will include
damaging winds, large hail, and tornadoes with the strongest
storms that develop.  In addition, thunderstorms will have the
potential to produce heavy rainfall rates especially across parts
of northern Arkansas, southern Missouri, and southern Illinois by
later today into tonight.  The relative fast forward motion of the
cold front will help limit the total rainfall amounts.
Nevertheless, the high rain rates associated with the severe
thunderstorms are expected to warrant a Slight Risk of flash
flooding across portions of southern Missouri into southern
Illinois through tonight.  Elsewhere, intense downpours can be
expected to accompany thunderstorms that are expected to become
severe across the lower Mississippi Valley and as far north as the
lower Great Lakes by this evening into the overnight hours.

By Sunday night, the center of the rapidly intensifying cyclone
will quickly exit into southern Canada.  However, the potent cold
front trailing south from the cyclone will sweep across the
east-central U.S. and the Deep South with a round to possibly
several rounds of strong to severe thunderstorms.  Meanwhile, a
swath of moderate to locally heavy rain will accompany the passage
of the cyclone across the Great Lakes on Sunday.  From Sunday
night into Monday morning, a squall line could be sweeping through
the entire East Coast with a round of strong to severe
thunderstorms ahead of the cold front.  By Monday morning, the
most active weather should be found across New England where
strong thunderstorms and locally heavy rain could be sweeping
across as a new low pressure system begins to develop.

Behind the rapidly intensifying cyclone in the East, strong and
gusty northwesterly winds will make for a breezy day across the
mid-section of the country on Sunday as a colder air mass from
Canada filters into the region.  However, a rapid warm-up is
forecast for the High Plains on Sunday, spreading into the
southern Plains by Monday ahead of another rapidly developing low
pressure system that will sweep across the Pacific Northwest on
Sunday and into the northern Plains by Monday morning.  This
system will signal the arrival of unsettled weather beginning
today through the weekend for the Pacific Northwest.  By Sunday,
high-elevation snow is expected to push further inland across
Idaho and then through the northern Rockies Sunday night into
Monday morning along with gusty winds.  Meanwhile, the Southwest
and the Four Corners will remain dry with a
gradual warming trend.

Kong


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

$$