405
FXUS02 KWBC 241830
PMDEPD

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
230 PM 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, supporting
precipitation chances over parts of the region. Overall, weather
across the lower 48 does not appear widely hazardous next week.


...Guidance/Predictability Assessment...

Models continue to show good overall agreement with the large
scale pattern across the country next week, with generally only
minor smaller scale spatial and temporal differences noted. The
differences in these details are more apparent with the positions
of a series of shortwaves spanning from the northwestern U.S. to
the central/northern Plains and Upper Midwest. Some of this energy
eventually shifts across the Great Lakes/Northeast as the week
progresses, with typical spread. The mid/upper pattern spanning
from the eastern Pacific into the Pacific Northwest, which models
initially struggled to resolve, now appears locked in with a
consensus for a Pacific Northwest/BC upper low Wednesday into
Thursday. Downstream ridging also seems well predicted. By Friday
and 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 still some
model variations on the handling of these shortwaves and the exact
depth and position of the trough axis, but the overall pattern
seems fairly well aligned at this time range all things considered.

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.
Meanwhile, broadening and deepening upper troughing across the West
may also direct more focused moisture and thus precipitation
chances into parts of the Four Corners states, but California is
starting to lean drier. Showers and thunderstorms could also 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/Miller


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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