986
FXUS02 KWNH 030649
PREEPD

Preliminary Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
148 AM EST Mon Nov 3 2025

Valid 12Z Thu Nov 06 2025 - 12Z Mon Nov 10 2025


...Overview...

The upper level weather pattern will initially be quite zonal
with several disturbances moving west to east across the country
on Thursday and Friday. The pattern is expected to amplify this
weekend 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. This pattern will drive a series
of progressive frontal systems across the nation later this week,
with persistent precipitation chances for the northern tier and
periods of precipitation for the Ohio and Tennessee Valleys as
well. Some wintry weather is expected in the high elevations in the
West and across northern New England. As the pattern amplifies, an
Arctic cold front should sink south across the Central and eastern
U.S., ushering in colder temperatures.


...Guidance/Predictability Assessment...

Model guidance is in good agreement on the overall large scale
pattern, with an expected amount of spread/uncertainty in the
details of individual systems. With zonal flow, the most uncertain
part of the forecast will be timing of back-to-back systems later
this week. The GFS and ECMWF are in unusually good agreement and
both show good run-to-run consistency, while the CMC seems to be
an outlier with significantly less consistency. Timing uncertainty
decreases later in the period as the pattern amplifies.

Given good agreement through the period, WPC`s forecast was
composed of a blend of the deterministic GFS and ECMWF and ensemble
means from the GEFS and ECENS. The weight placed on ensemble means
was increased through the period to help smooth out differences in
individual systems. This blend maintained good continuity with the
previous forecast.


...Weather/Hazards Highlights...

The first frontal system will track across the northern tier
Thursday into Friday while the next system moves onshore in the
Pacific Northwest. The leading system will bring precipitation
chances from the Upper Midwest/Great Lakes to the Northeast and
down into the Ohio and Tennessee Valleys. Locally heavy rainfall
may be possible in the warm sector of the system over the Ohio and
Tennessee Valleys, and wintry weather will be possible on the
northern side of the system across northern New England.

In the Northwest, anomalous Pacific moisture will move onshore
with the second system on Thursday, resulting in widespread
precipitation chances with moderate to locally heavy rain and
mountain snow across western Washington and Oregon and northwestern
California. Precipitation rates will likely be high enough to pose
a risk of isolated instances of flash flooding, especially near
steep terrain and burn scar areas, and there is a Marginal Risk of
excessive rainfall in effect for Thursday. Precipitation chances
will continue across the Northwest through the end of the week, but
precipitation intensities are forecast to decrease.

As the second frontal system pushes east late this week into the
weekend, precipitation chances will expand into the north-Central
U.S. and once again to the Great Lakes, Northeast, and Ohio and
Tennessee Valleys. While moisture from the second system enters the
north-Central U.S. Friday into Saturday, an Arctic cold front will
dip south into the region as well, creating chances of wintry
weather across the northern Plains and Upper Midwest. Another shot
of wintry weather will also be possible across the Northeast on
Saturday and Sunday as the low pressure center tracks across the
region. The Arctic front will continue to push south across the
Central and eastern U.S. this weekend into early next week,
ushering in colder and drier air. Meanwhile, the next system will
approach the West Coast and stall, creating coastal precipitation
chances on Saturday and Sunday.

For much of the southern and Central U.S., weak upper level
ridging will keep the forecast dry with above average temperatures
through the end of the week. High temperatures are forecast to run
10-20 degrees above average. As the pattern amplifies over the
weekend and early next week, upper level ridging and above normal
temperatures will build over the Intermountain West while upper
level troughing and below normal temperatures develop in the East.


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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