929
FXUS02 KWBC 041949
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
249 PM EST Tue Nov 4 2025

Valid 12Z Fri Nov 07 2025 - 12Z Tue Nov 11 2025


...Overview...

The upper level pattern will feature relatively zonal flow through
the end of the week, with two back-to-back embedded disturbances
sweeping across the nation. These disturbances will drive two
progressive frontal systems that will bring precipitation chances
to the Northwest, north-Central, and Eastern U.S., with chances for
wintry precipitation across the northern tier. The pattern is
expected to amplify this weekend into early next week as a deep
upper low/trough approaches the West Coast while strong ridging
develops over the Intermountain West and strong troughing develops
over the East. As the pattern amplifies, a strong Arctic cold front
will sink south across the Central and Eastern U.S., ushering in
colder temperatures. Meanwhile, another frontal system will
gradually push onshore in the Northwest, while a cutoff low
develops over the Pacific off the California coast.


...Guidance/Predictability Assessment...

The latest 00/06Z guidance remains in good agreement on the
overall pattern across the CONUS, specifically the trend from a
more zonal to amplified pattern this weekend. Usual smaller-scale
timing and location differences exist with a couple initial upper-
waves/surface systems expected to pass across the central to
eastern U.S. in the initially zonal and progressive flow late this
week, including a clipper system across the northern tier.
Meanwhile, as these systems pass buy, all guidance shows a
deepening upper-low over southeastern Canada and an amplifying
trough over the central to eastern U.S., with an upper-ridge
building in tandem across the western U.S. By early next week
guidance begins to diverge a bit more with respect to an upstream
upper- trough over the northeastern Pacific and the evolution of
this feature as it translates eastward. This includes the potential
for splitting upper- energies approaching the ridge and how fast
and how much a potential northern split would help to break down
the ridge. The degree to which the upper-ridge remains amplified
compared to the approach of this upper-energy will impact the
timing and amount of potential precipitation for the Pacific
Northwest to northern Rockies.

The updated WPC forecast used a composite blend of the 00Z
ECMWF/CMC and 06Z GFS given good overall agreement, with a bit more
weight for the GFS/ECMWF given closer similarities on some of the
smaller scale details. A contribution from the 00Z ECens/GEFS means
was included as 40 and then 50% of the blend for the latter part
of the forecast period as details more rapidly diverged with
respect to the Pacific Coast/western U.S. system. QPF wise, the
ECMWF/GFS were used to help augment amounts a bit over the northern
Plains to Midwest as more precipitation was indicated with the
clipper system compared to the NBM. Lake effect amounts were also
augmented using the ECens mean in the Great Lakes region this
weekend. The ECens/GEFS mean were used to bring amounts/coverage up
a bit in the Pacific Northwest/northern Rockies early next week
given the increasing uncertainty in the deterministic guidance
likely bringing amounts down.


...Weather/Hazards Highlights...

A frontal system will sweep quickly across the Eastern U.S. Friday
into Saturday with widespread precipitation chances from the Great
Lakes and Northeast to the interior Southeast. Locally heavy
rainfall may be possible in the warm sector of the system over the
Ohio and Tennessee Valleys, but the frontal system should be
progressive enough to limit any flash flood threat. On the northern
side of the system, colder air will allow for wintry weather
across the Great Lakes and northern New England.

The next frontal system will follow quickly behind the first,
entering the West Coast on Friday and reaching the East Coast on
Sunday. Precipitation chances will focus over the northern tier
with this system, and more wintry weather will be possible as
Pacific moisture interacts with cold, Arctic air surging south out
of Canada on the backside of the system. Wintry weather will be
likely on Friday in the high elevations of the Northwest and will
be possible Saturday and Sunday from the Northern Plains to the
Great Lakes and New England. Some gusty winds are also expected
along the northern Rockies and portions of the adjacent High Plains
late this week as the system passes by. Wintry weather chances
will likely linger across the Great Lakes, Appalachians, and New
England through early next week underneath a deep upper level
low/trough, and given the cold air in place it isn`t out of the
question some flurries may mix in for the Mid- Atlantic.

The cold and dry Arctic air moving south out of Canada will drive
a cold front across the Central and Eastern U.S. early next week,
which will cause temperatures to drop to 10-15 degrees below
average. High temperatures are forecast to only reach the 30s
across the Upper Midwest, Great Lakes, and northern New England,
and a broad area of lows into the 30s is expected across the
Ohio/Tennessee Valleys, the Mid-Atlantic, and possibly as far south
as the inland Gulf Coast region. This would be the first
frost/freeze of the season for many locations. Meanwhile, strong
ridging developing over the Intermountain West will allow
temperatures to rise to 10-15 degrees above average.

The next system will slowly approach the West Coast early next
week, creating coastal precipitation chances from Washington to
Central California Sunday through Tuesday. Precipitation may spread
towards the interior Northwest Monday or Tuesday, but the timing
and progression of this system is still uncertain.


Putnam/Dolan


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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