Prognostic Meteorological Discussion
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FXUS21 KWNC 141856
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT October 14 2025

SYNOPSIS: Strong low pressure at the surface and mid-levels is favored to shift
from the Bering Sea into the Gulf of Alaska early in week-2, bringing with it
potentially hazardous wind and precipitation initially to portions of Alaska,
then into the Pacific Northwest by the middle of week-2. Widespread surface
high pressure east of the Rockies throughout the forecast period precludes the
potential for hazardous weather for most of the Contiguous U.S. (CONUS),
although a strong pressure gradient near the margin with the surface low over
the Pacific Northwest favors enhanced winds for portions of the Northern and
Central Rockies and Northern Plains.

HAZARDS

Moderate risk of high winds for the Aleutians, Alaskan Peninsula and the
western coast of Alaska south of Norton Sound, Wed, Oct 22.

Slight risk of high winds for the Alaskan Peninsula as well as much of the
western and southern coasts of Mainland Alaska, Wed-Fri, Oct 22-24.

Slight risk of high winds from Cape Mendocino north to Puget Sound, Wed-Tue,
Oct 22-28.

Slight risk of high winds for portions of the Northern and Central Rockies and
much of the Northern Plains, Wed-Tue, Oct 22-28.

Slight risk of heavy precipitation for coastal southeastern Alaska east of
Prince William Sound, Wed, Oct 22.

Slight risk of heavy precipitation for much of coastal Oregon and Washington,
Fri-Tue, Oct 24-28.

Slight risk of heavy snow for the Northern Cascades, Fri-Tue, Oct 24-28.

Slight risk of heavy for portions of the Northern Rockies, Fri-Tue, Oct 24-28.

DETAILED SUMMARY

FOR FRIDAY OCTOBER 17 - TUESDAY OCTOBER 21:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR WEDNESDAY OCTOBER 22 - TUESDAY OCTOBER 28: Today`s model solutions continue
to depict a strong mid-level trough and associated surface low pressure over
the Bering Sea at the outset of week-2. These features are favored to shift
eastward quickly and become established over the Gulf of Alaska, shifting high
winds and heavy precipitation from Alaska early in week-2 to the Pacific
Northwest by the middle of week-2. Ensemble means for the surface low pressure
center get as low as 982 hPa in the GEFS, and both the GEFS and ECENS are in
very good agreement on the strength and evolution of this significant system.
Uncalibrated probabilistic output from both models show chances exceeding 70%
for more than 2 inches over a three-day period for much of Southeastern Alaska,
with most of that total coming on day-8 (Oct 22), warranting a continuation of
the slight risk of heavy precipitation for Southeastern Alaska east of Prince
William Sound for Oct 22. High winds also continue to be a concern with this
system for Alaska. Very tight pressure gradients are depicted over much of
southern and western Alaska, especially at the outset of the forecast period.
This is further supported by the ECMWF Probabilistic Extremes Tool (PET), which
indicates widespread 20% or higher probabilities of 3-day maximum wind speed to
exceed the 85th climatological percentile and at least 40mph early in week-2,
with a diminishing signal as the week progresses. A moderate risk of high winds
is maintained for much of the Alaskan west coast and Alaskan Peninsula for Oct
22, while a slight risk of high winds is posted for the above areas as well as
the southern coast of Alaska as far as Yakutat for Oct 22-24.



By the middle of week-2 this system is favored to shift into the Gulf of
Alaska, where models depict an interaction with a long plume of enhanced
atmospheric moisture, resulting in potentially hazardous precipitation for much
of the Pacific Northwest in addition to high winds associated with continued
tight pressure gradients along the coast. Uncalibrated probabilities from the
GEFS and ECENS show chances of at least 30% for 3-day precipitation to exceed 2
inches by the middle of week-2, while both the GEFS and ECMWF PETs indicate at
least a 20% chance of three-day precipitation to exceed the 85th percentile for
much of the Pacific Northwest and Northern Rockies, with the GEFS PET for snow
water equivalent (SWE) indicating the potential for heavy snow in higher
elevations. A slight risk of heavy precipitation is posted for much of the
Oregon and Washington coasts for Oct 24-28, as well as a slight risk of heavy
snow for the Northern Cascades and Northern Rockies, also for Oct 24-28. A
slight risk of high wind is posted for all of week-2 for western coast of the
CONUS from Cape Mendocino north to Puget Sound, as well as for the Northern
Rockies and much of the Northern Plains where the periphery of the incoming
surface low pressure will form another zone of tight gradients with surface
high pressure that dominates most of the rest of the CONUS throughout the
forecast period.

FORECASTER: Danny Barandiaran

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