Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
300 AM EST Thu Dec 11 2025

Valid 12Z Thu Dec 11 2025 - 12Z Sat Dec 13 2025

...Ongoing Atmospheric River event over the Pacific Northwest to diminish
today...

...Arctic air surges south into the Northern Plains late today and Friday;
Upper Midwest this weekend...

...Active lake effect snows downwind of Lakes Erie and Ontario...

...Fast moving low to bring moderate to heavy snows from the Mid
Mississippi Valley into the Central Appalachians; Mid-Atlantic this
weekend...

...Much above average temperature expected from the West coast, across the
Rockies, Central to Southern Plains into the Lower Mississippi Valley..

The atmospheric river that has produced 5 to 10+ inches of rain atop the
Pacific Northwest over the last several days will finally come to an end
today as moist onshore flow weakens in response to an amplifying mid to
upper- level ridge along the West coast.  While the heaviest rainfall is
subsiding, lingering rain through Friday will exacerbate ongoing major
river flooding, and landslides will continue across portions of western
Washington state and northwest Oregon for several days.

In addition to bringing an end to the wet Pacific Northwest pattern, the
amplifying West Coast ridge will also dislodge Arctic air southward into
the Northern Plains late this afternoon. Much above average temperatures
over the Northern Plains today will plummet 30 to 40 degrees in parts of
the Northern Plains as the front surges southward, translating to high
temperatures in the single digits across North Dakota into central Montana
by tomorrow. As the frigid airmass spreads southeastward into the Upper
Midwest and upper reaches of the Ohio Valley, daytime highs will struggle
to break the teens by Saturday. Cold air moving across the relatively warm
great lakes will also support active lake effect snows downwind of Lake
Erie and Lake Ontario, where snow totals of 6-10" and wind gusts of 40 mph
are possible through tomorrow morning.

Accumulating snows are also possible today into early Friday in
association with a fast moving area of low pressure dropping southeastward
from the Central Plains into the Ohio Valley. This will support a narrow
axis of 2-4" of snowfall on the northern flank of the low track through
the Mid-Mississippi Valley, Ohio Valley, and Central Appalachians. West of
the snowfall axis, upwards of a tenth of an inch of freezing rain is also
possible today over the central Dakotas and eastern Montana. As a whole, a
look at the Watch-Warning map this morning shows a swath of Winter Weather
Advisories across the Northern High Plains and Ohio Valley in anticipation
of this system today. Beyond Friday, this system is expected to spread
wintry precipitation into the northern Mid-Atlantic, where the current
forecast calls for an inch or two of snow along the I-95 corridor between
Philadelphia and Washington D.C.    

While large sections of the north central to eastern U.S. will have below
average temperatures over the next few days, the opposite will be true
across the West from the West coast into the Great Basin, Southwest and
Rockies.  High temperatures are expected to be 10 to 20 degrees above
average today and Friday across these areas.  The exception to this will
be in the interior Central Valley of California where fog and low clouds
are expected to persist and keep temperatures much cooler than surrounding
areas that will be cloud free.  In the cloud free areas, there is the
potential for several record high afternoon temperatures and record high
morning low temperatures late this week into this weekend across large
portions of the western U.S.  Much above average temperatures also on tap
for the Central to Southern Plains today and Friday and eastward into the
Lower Mississippi Valley and Central Gulf Coastal region on Friday.


Asherman/Oravec


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