928
FXUS02 KWBC 010800
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
300 AM EST Mon Dec 1 2025

Valid 12Z Thu Dec 04 2025 - 12Z Mon Dec 08 2025

...Heavy rains Thursday and into the weekend for parts of the Gulf
Coast and Southeast...


...Overview...

A sprawling deep and cold low will persist over Hudson Bay through
the medium range period, maintaining below normal temperatures for
the central and eastern U.S.. Upper ridging enters the Pacific
Northwest midweek and will expand at times over The West allowing
above normal temperatures to return there. Upper troughing moving
through the Southwest by Thursday will slowly shift east over the
southern Plains through Friday which will promote heavy rain
chances downstream along the Gulf Coast and Southeast Thursday into
this weekend. Wintry weather potential is possible on the north
side of the precipitation shield with another possible nor`easter
for the Northeast this weekend. A couple of clipper type systems
will impact the northern tier states as well through the period.


...Guidance/Predictability Assessment...

The Southwest trough continues to show good agreement on the large
scale, but plenty of uncertainty in the details impacting sensible
weather. A couple of other pieces of energy within the larger
trough across the Central-Eastern U.S. show a lot of variability.
This impacts evolution of possible surface low development over the
Southeast later this week, and progression of that low up the East
Coast. The ECMWF had been the most bullish on Nor`easter
development, but the new 00z run this evening did shift more
towards the suppressed solutions. This will need to continue to be
monitored. For now, a general model compromised seemed to serve as
a good starting point.

Otherwise, uncertainty in weak systems through the U.S. become
more unclear later in the period. The GFS was notably stronger with
the next shortwave into the West than consensus. WPC leaned more
heavily on the ECMWF with the ensemble means for the latter half of
the medium range period.


...Weather/Hazards Highlights...

Lake effect snow will linger over the Great Lakes into Thursday as
mountain snows occur over the southern Rockies. Heavy rain will
spread over the Central Gulf Coast by Thursday, expanding into the
Southeast Friday into the weekend. The WPC Day 4/Thursday ERO
continues to show a marginal risk from Houston and across southern
Louisiana. The marginal risk expands considerably into much of the
Southeast along the frontal boundary which may stall for a period
of time allowing for some training of storms. Instability may be
lacking overall though which should limit the flash flood threat.
After this, low pressure likely develops near the East Coast this
weekend, though the direction of the track (whether straight out to
sea or northeast along the coast) remains uncertain, so stay tuned
for potential winter weather this weekend. But there is some
signal for winter weather on the north side of the precipitation
shield.

Surges of below average temperatures continue for the central and
eastern U.S. into late week as the sprawling low over Hudson Bay
persists. A surge from the northern Plains through the Northeast
occurs into Friday with max temperatures of 15 to 25 degrees below
zero. Wind chills of -20 to -30F are forecast for portions of the
northern Plains and Upper Midwest Thursday morning. The next cold
surge may be of similar magnitude and should follow a similar track
this weekend. Temperature relief comes to The West with ridging
and above normal temperatures expected across the Southwest through
the Great Basin late week through this weekend.


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





$$