515
FXUS02 KWNH 280716
PREEPD

Preliminary Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
215 AM EST Fri Nov 28 2025

Valid 12Z Mon Dec 01 2025 - 12Z Fri Dec 05 2025


...Storm system brings enhanced rainfall to the Southeast/East
Coast Monday-Tuesday with possible wintry weather to its north,
especially into the Interior Northeast...


...Overview...

The medium range period looks fairly active over the lower 48 next
week with a couple of impactful shortwaves rounding the base of an
upper low anchored over the Hudson Bay. By Monday, a shortwave
will be coming through the Four Corners region into the southern
tier, as a surface low materializes near the Gulf Coast. This
shortwave will deepen as it lifts up the East Coast spreading
possibly heavy precipitation from the South into the East early to
mid next week, with some snow and ice possible on the northern side
of the precipitation shield. The best chance of snow will be
across interior New England. The next shortwave will dive into the
West next Wednesday, with plenty of uncertainty on its evolution
later in the week.


...Guidance/Predictability Assessment...

The models continue to have a good handle on the larger scale
pattern for next week, but plenty of uncertainty in the details
that could have impacts on sensible weather. With the first
shortwave, models continue to show some uncertainty in the timing,
but not too significant. Details of this system however are still
quite uncertain and make for a tricky forecast in terms of
precipitation types on the northern side of the precipitation
shield, although there seems to be a trend away from any meaningful
snows closer to the East Coast.

The next trough coming into the West does show somewhat more
synoptic scale model differences, with uncertainty of how much
energy could pull off into the southern stream and potentially form
a closed low over or near southern California. The ECMWF and CMC
both show more stream separation and are supported by the ensemble
means. The 18z GFS was much faster with a more elongated trough (an
outlier from prior runs), but the new 00z run tonight came more in
line.

The WPC forecast tonight was able to use a multi-model blend
early, with increasing weighting from the ensemble means to 60
percent of the blend by the end of the period. Generally maintained
good agreement with WPC continuity as well.


...Weather/Hazards Highlights...

An area of snow associated with the next shortwave digging across
the western U.S. should eventually spin up a wave of low pressure
along the Gulf Coast and lift up the East Coast as well. It appears
that the central Gulf Coast into the Southeast and East Coast may
be the prime location of seeing heavy rain from this developing
system, although the speed of motion of this system will probably
limit the total rainfall amounts. Still, given the dynamics and
moisture, do have a marginal risk for Monday`s ERO from the central
Gulf Coast into the Southeast. For Tuesday, a marginal risk was
drawn from eastern North Carolina northward to Cape Cod, generally
along and east of the I-95 corridor. Meanwhile, the northern extent
of this developing system will likely have wintry weather
concerns. Generally, some light snow is possible across Kansas
early in the week, possibly spreading across the Middle Mississippi
Valley into much of the Ohio Valley, with high uncertainty in the
details. Light freezing rain is also a concern, with areas of
Arkansas and then into the southern/central Appalachians showing
the highest possibility for that. Then as the low tracks into the
western Atlantic by Tuesday, snow could occur across the
Appalachians to interior Mid-Atlantic and Northeast. All of this is
still rather uncertain as small changes to the low track could
yield large differences in precipitation amounts and type.

A northern stream shortwave through the Upper Midwest and Great
Lakes behind this main system will bring additional light snows to
parts of this region with some likely lake enhancement in downwind
favorable locations.

The next system into the West mid next week should support low
elevation rain and mountain snow in the Pacific Northwest to the
Intermountain West and Rockies. Precipitation should also increase
across the Southwest, and possible again across the Gulf Coast.

Widespread and persistent below average temperatures for this time
of year can be expected for the central U.S. in particular for at
least the first half of the week as arctic air spills south. The
coldest anomalies for both highs and lows (around 15-25 degrees
below normal) are forecast over the Plains and Mississippi Valley
Sunday, and into the Midwest Monday- Tuesday given the snow cover
there. Lows are likely to be below 0F in the northern Plains to
Minnesota into Monday, with highs in the teens. Rounds of cooler
than average temperatures are likely in the East as well, but with
anomalies closer to 5-15 degrees below normal, aside from Florida
that should be warmer than average by a few degrees. The Rockies
westward should be more near or slightly above normal for most of
the period with cold air retreating eastward for the Central U.S.
by next Friday.


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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