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FXUS02 KWNH 100523
PREEPD

Preliminary Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1222 AM EST Wed Dec 10 2025

Valid 12Z Sat Dec 13 2025 - 12Z Wed Dec 17 2025


...Potentially hazardous cold is possible for portions of the
Northern Plains and Upper Midwest this weekend...


...Overview...
Multiple shortwaves traversing through a broad upper low/trough
east of the Rockies early on will keep the northern tier of the
country in an active pattern. An arctic airmass will lie across
portions of the north- central U.S. bringing much below normal
temperatures and potentially hazardous cold. Broad ridging will
persist along the West Coast/Rockies through this weekend
continuing their anomalous warmth. Early to mid next week, the flow
pattern becomes quasi-zonal which should lead to renewed heavy
rain/snow in the Pacific Northwest and Northern Continental Divide.
Initially, generally progressive clipper systems will be favored
in this pattern east of the Rockies with enhanced northern tier
wind/snow chances and lake effect snow in the lee of the Great
Lakes, but that becomes a memory by mid next week.


...Guidance/Predictability Assessment...
The latest suite of guidance shows shortwave issues, but agrees on
the idea of the flow pattern becoming zonal. A general blend of
the globals early with some 12z ECMWF/12z NAEFS mean contribution
late were used to initialize the surface fronts/pressures/500 hPa
heights. The QPF started with the 01z NBM but needed increases in
most spots in order to get better magnitude, with the bigger
adjustments near the Great Lakes early to mid period and Gulf Coast
for much of the medium range period, which led to adjusted PoPs.
Winds also needed increases from the 01z NBM.  For the remainder
of the grids, the 01z NBM seemed like a better starting point.


...Weather/Hazards Highlights...
While some precipitation continues for the Northwest/Northern
Rockies early on, it increases in coverage early to mid next week
as the general flow pattern attempts to become more zonal. Snow is
remains possible in the highest terrain of the Washington Cascades
and increasingly possible across the Northern Continental Divide.

Shortwaves rounding the base of the trough centered over the
eastern third of the country will bring rounds of generally light
to moderate precipitation, mainly snow, into the Midwest/Great
Lakes and eastward towards the Appalachians and Northeast through
the weekend. To the South, reinforcing fronts slowing as they
approach Florida/the Gulf Coast will bring the threat of rain,
potentially heavy early next week near the western Gulf Coast.

Daily temperatures as much as 15F to 25F above seasonal average
will spread from the West into the the adjacent High Plains/Plains
early to mid next week. In contrast, 20F to 30F below average
temperatures remain forecast Saturday into Monday from the
Northern Plains across the Great Lakes, Midwest, and Ohio Valley
will weaken somewhat as the airmass migrates into the East next
Tuesday. This may result in hazardous cold as morning temperatures
dip below zero with wind chills near -20 degrees.  Much of the
South, Gulf Coast, and Florida will be near normal through the
period, with the East Coast and Great Lakes joining in on the
relative thaw by next Wednesday.

Roth


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw














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