384
FXUS02 KWBC 291940
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
240 PM EST Sat Nov 29 2025

Valid 12Z Tue Dec 02 2025 - 12Z Sat Dec 06 2025


...Heavy snow chances from the Central Appalachians through
southern New England just inland from the coast, with heavy
rainfall potential over the Carolinas, Mid-Atlantic Coast, to
southeast Massachusetts...


...Overview...

Next week remains cold and active over much of North America
because of a sprawling deep and cold low that settles over Hudson
Bay by Tuesday. Some ridging gets into the Pacific Northwest later
in the week, but otherwise cyclonic flow around this vortex rules
the pattern.
A shortwave trough rounding this vortex crosses the Mid-South early
Tuesday before swinging across the Eastern Seaboard Tuesday night.
Rapid surface low pressure development occurs ahead of this wave
along the Carolina Coast Tuesday with the system becoming a full-
fledged nor`easter off the Mid-Atlantic coast by 00Z Wednesday,
though it rapidly shifts northeast and away from New England by 12Z
Wednesday.
The next notable wave dives south from the Pacific Northwest on
Tuesday, reaching southern California late Wednesday. Uncertainty
remains on the next moves of this low, but there is confidence of
heavy rain downstream along the Gulf Coast and Southeast through
the latter half of the week given the broad southerly flow ahead of
the slow moving wave.


...Guidance/Predictability Assessment...

The proximity of the track of the nor`easter to the Northeastern
Seaboard still has variability among guidance, though all agree on
a progressive system with a rapid exit Tuesday night. The 12Z EC
remains a little farther offshore which would bring snow to the
Northeast coast. However, the consensus is still a little closer
which brings rain, potentially heavy, along the Mid-Atlantic and
southern New England coasts.

Out West, the main question is whether the western midweek trough
closes into a cutoff low over or south of southern California as
the EC and UKMET continue to do or if it partially develops over
Arizona Wednesday night and shifts east as the GFS and now the 12Z
CMC (the 00Z CMC was farther west than the 12Z). A good tiebreaker
for these situations has been the EC-AIFS which continues to favor
the more eastern/less cutoff solution. The closest solution to both
the 06Z ECAIFS was the 00Z CMC which was heavily favored in the WPC
blend this morning through Day 5 as this is the main feature after
the Nor`easter. Uncertainty remains for Days 6/7 with the ECAIFS
being more progressive, but until the deterministics come in line
better on the southwest trough/low favor goes to the ensemble
solutions. The 06Z GEFS was closest to the 06Z EPS-AIFS, so that
was given extra weight in the blend.

WPCQPF Days 4-7 was blended from the 13Z NBM using the 00Z CMC, the
06Z EC-AIFS, the NBM 50th percentile, and some GFS as needed. This
still highlights heavy rain for the Gulf Coast into the Southeast
Wednesday night into the weekend which is the main QPF concern. The
CMC was also helpful in boosting lake effect QPF in the continued
cyclonic flow over the Great Lakes.


...Weather/Hazards Highlights...

A nor`easter develops along the Carolina Coast Tuesday and shifts
off the New England Coast Tuesday night. This fast moving low
should bring heavy snow to areas in the Northeast away from the
coast with heavy rain across the Carolinas and depending on the
track up the Mid-Atlantic and southern New England Coasts. The Day
4 Excessive Rain Outlook continues to include a Marginal Risk over
these areas. A brief wintry mix is also likely Tuesday in eastern
portions of the central Appalachians.

There is then a lull in heavy rain until Wednesday night when a
rather positively-tilted upper trough slowly moves through the
Southwest. Strong flow over the Gulf will allow heavy rain to
develop over the western Gulf Coast and persist/slowly shift ENE
through Georgia into the weekend.

Impulses and shortwave trough crossings should continue to being at
least periodic lake effect snows to typical snow belts off the
Great Lakes Wednesday through the weekend.

Widespread and persistent below average temperatures can be
expected to sweep across the Lower 48 next week under the sprawling
low vortex centered over Hudson Bay. Expect high temperatures of 15
to 20 degrees below normal to spread from the Rockies and northern
Plains Wednesday through the Midwest to southern Plains Thursday,
and the Northeast on Friday. Wind chills look to bottom out around
-20F in the Upper Midwest Thursday morning, which should approach,
 but may not go below the locally-set criteria for a Cold Weather
 Advisory. Temperature relief comes in the form of an upper ridge
 extending into the Northwest Thursday, though the progression (or
 lack thereof) of the low over the Southwest should determine how
 far inland the warmer air pushes. As of now the western U.S.
 should return to above normal temperatures by this weekend.


Jackson


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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