983
FXUS02 KWBC 030658
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
158 AM EST Wed Dec 3 2025

Valid 12Z Sat Dec 06 2025 - 12Z Wed Dec 10 2025


...Overview...

An Central to Eastern U.S. mean upper trough and broad cyclonic
flow with reinforcing shortwaves will continue to dominate during
much of the medium range period across the CONUS as a result of
upper lows anchored over eastern Canada and Alaska. This will favor
below to well below normal temperatures for the Plains to the East
Coast. Near to above normal temperatures are favored for the
Western states under the influence of upper ridging. A lingering
frontal system over the Southeast will likely promote an area of
locally heavier rain while a couple of clipper systems will impact
the northern tier states as well with with a modest snow chances.
Heavier coastal rains and terrain enhanced snows may develop inland
from the Pacific Northwest through the northern Rockies early next
week along with a threat of high winds to monitor.

...Guidance/Predictability Assessment...

Guidance continues to show good agreement synoptically through the
medium range period but there remains quite a bit of uncertainty
in the details and the timing of multiple shortwaves through the
northern tier impacting sensible weather grids. A general blend of
the deterministic guidance continues to offer a good starting point
for the first half of the period, with increasing weighting of the
ensemble means onward into Days 6 and 7. This meant the 01 UTC NBM
was a good starting point for most of the sensible weather grids,
but did have to supplement QPF with ECMWF guidance to increase
coverage of light precipitation associated with systems moving
broadly through the U.S. northern tier states days 4-6.

...Weather/Hazards Highlights...

Heavy rain along a frontal boundary should continue into Saturday
for parts of the Southeast. The WPC Day 4/Saturday ERO shows a
Marginal risk from the Florida Panhandle to far southern Georgia,
along the frontal boundary, which may stall for a period of time
allowing for some training of storms. Instability may be lacking
overall which should limit the flash flood threat toward the I-10
corridor. By Sunday, some of the guidance is showing rainfall
hanging around along the trailing cold front in Florida, but with
overall lower amounts and so opted for no risk areas at this time
for the Day 5 ERO tonight. Over the Pac NW, several Pacific systems
will push into western Canada during the period with rain/snow
over WA/OR and eastward to the Northern/Central Rockies. This
activity should be on the increase along with the potential for
terrain enhanced high winds next week. Several clipper like systems
will also bring some rain and snow to parts of the Midwest, Great
Lakes/Appalachians and the Northeast.

Temperatures across the north-central U.S. to the East will remain
below normal at least through the weekend, with some moderation
from west to east early next week. This weekend, daytime highs and
morning lows could be 10-15 degrees below normal in the Northern
Plains/Upper Midwest, with this airmass transitioning into the East
on Monday. The West will trend warmer into early next week
underneath upper ridging, with warmer than average temperatures
also spreading into the central and southern Plains next Tuesday
and Wednesday.


Santorelli


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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