410
FXUS02 KWBC 240722
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
322 AM EDT Sat Oct 24 2026

Valid 12Z Tue Oct 27 2026 - 12Z Sat Oct 31 2026


...Overview...

An upper trough will be atop the northwestern U.S. as the medium
range period begins Tuesday, with embedded shortwaves providing
rain and snow to the Pacific Northwest, northern Rockies, and
across the Upper Midwest as some energy pivots east. There is
increasing model agreement that an upper low will develop atop the
Pacific Northwest and British Columbia Wednesday-Thursday,
maintaining the same type of general flow pattern. Downstream upper
ridging will allow for warmer than average temperatures to spread
across much of the eastern half of the U.S. through the week.
Rounds of rain and thunderstorms are possible across the south-
central U.S. with favorable flow aloft. Into late week, upper
troughing is forecast to deepen in the West and allow for
precipitation. Overall, weather across the lower 48 does not appear
widely hazardous next week.


...Guidance/Predictability Assessment...

The past couple of model cycles have fortunately shown increased
agreement with the synoptic scale pattern across the lower 48 next
week, though with some typical detail differences. Some of these
detail differences are present early in the period with exact
positions of multiple shortwaves in the northwestern to north-
central U.S., with some energy shifting across the Great
Lakes/Northeast as the week progresses. But did not note any real
outliers with these, and a model blend cut down on favoring any
particular model. Then models now show better consensus for a
Pacific Northwest/BC upper low Wednesday-Thursday, after the 12Z
ECMWF finally flipped to that pattern and looked more like the rest
of the guidance, and the new 00Z ECMWF is consistent with it.
Downstream ridging also seems well predicted. By Friday-Saturday,
some southern stream energies are forecast to pivot around the base
of the Northwest upper low/trough, which should deepen the upper
trough overall in the West. There are some model variations on
handling of the shortwaves and the exact depth and position of the
trough axis, but nothing out of the question for a late medium
range forecast.

Given reasonably good model agreement on the large scale, used a
multi-model blend of the dynamical and AI guidance through much of
the period. Included some ensemble means in the fronts/pressures
forecast by the latter part of the period to smooth out individual
model differences.


...Weather/Hazards Highlights...

Multiple rounds of rain and higher elevation snow are forecast for
the Pacific Northwest across the northern Great Basin and Rockies
next week under a couple of upper troughs. Shortwaves in the
northern tier will also support precipitation in the north-central
U.S., and some snow could mix in at times even in lower elevations
of the northern Plains. Farther south, rain and thunderstorms are
possible in the southern/central Plains. Rain totals look to be
light through midweek, but may increase by later next week.
Broadening and deepening upper troughing across the West could
bring precipitation into California and the Great Basin into the
Four Corners states, but the details are yet to be determined.
Additionally, showers and thunderstorms could affect at least the
east coast of Florida in easterly flow behind a stalled front
farther south.

Warmer than average temperatures are expected for portions of the
central and eastern U.S. from day to day under mean upper ridging.
Highs in the 70s are forecast as far north as the Mid-Mississippi
and Ohio Valleys. Temperatures should be near average to slightly
below average for highs in the western U.S. next week.


Tate


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, excessive rainfall outlook,
winter weather outlook probabilities, heat indices and Key Messages
are at:

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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