093
FXUS21 KWNC 301821
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT October 30 2026

SYNOPSIS: Multiple model ensembles indicate a very potent and long-lived area
of low pressure at the surface and mid-levels over the North Pacific, bringing
the potential for a variety of hazardous weather to portions of the West Coast.

HAZARDS

Slight risk of heavy precipitation for western portions of Washington, Oregon,
and California as far south as Cape Mendocino, Sat-Fri, Nov 7-13.

Slight risk of heavy snow for the Cascade and Klamath Mountains, Sat-Fri, Nov
7-13.

Slight risk of high winds for coastal portions of Washington, Oregon, and
California as far south as Cape Mendocino, Sat-Fri, Nov 7-13

Slight risk of heavy precipitation for western portions of Northern California
south to Monterey Bay, Tue-Fri, Nov 10-13.

Slight risk of heavy snow for the northern Sierra Nevada, Tue-Fri, Nov 10-13.

Slight risk of high winds for coastal portions of Northern California south to
Monterey Bay, Tue-Fri, Nov 10-13.

DETAILED SUMMARY

FOR MONDAY NOVEMBER 02 - FRIDAY NOVEMBER 06:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR SATURDAY NOVEMBER 07 - FRIDAY NOVEMBER 13: The main story from a hazards
perspective continues to be a potentially potent storm system over the North
Pacific. Multiple models depict a deep surface low and mid-level trough to
become established over the Gulf of Alaska by the outset of week-2, slowly
expanding southward through the forecast period. This feature has been noted in
ensemble solutions for several days now, with the big question remaining how
far south the trough shifts, and to what extent it induces deep moisture
advection onshore. For now the models continue to push back the arrival of the
most intense precipitation potential into the second half of the forecast
period, precluding any increase in forecast confidence. For now the consensus
among the model ensembles is that this system will likely be a slow mover, but
with remarkable staying power. However, for now most of the energy from this
storm system is favored to remain focused on the Canadian coast.



That said, there is still the potential for hazardous weather from this system
for much of the Pacific Northwest throughout the forecast period, with this
potential expanding into northern California in the second half of week-2.
Uncalibrated probabilities from the GEFS indicate at least a 20% chance of
3-day accumulated precipitation exceeding an inch with the highest
probabilities near Puget Sound, and 24hr precipitation accumulation totals from
the GEFS and ECENS ranging from a quarter inch to an inch from Cape Mendocino
northward from the Cascades to the coast. Given this, the slight risks of heavy
precipitation for lower elevations and heavy snow for the Cascades and Klamath
mountains remains posted in today`s outlook, now extended to cover all of
week-2 (Nov 7-13). A slight risk of high winds also remains posted along the
coast from Cape Mendocino to the U.S.-Canada border, valid Nov 7-13.



As noted, today`s model solutions noticeably bring the trough farther south and
with it the potential for hazardous weather farther south into California. Both
the GEFS and ECENS 24hr precipitation totals show a significant uptick in
potential accumulations southward to Monterey Bay around day-11 (Nov 10). One
model or the other has hinted at this southern extension for a few runs, and
with both models coming into better alignment, slight risks for heavy
precipitation and high winds are added to today`s outlook covering coastal
portions of California as far south as Monterey Bay, along with a slight risk
of heavy snow for the northern Sierra Nevadas, all valid Nov 10-13.



While this potentially potent storm system is likely to result in periods of
strong winds and heavy precipitation along the southern and southeastern coast
of Alaska as well, hazardous thresholds are not expected to be exceeded so no
hazards are posted for Alaska at this time. In southwestern Alaska, much above
normal temperatures are forecast in week-2, which is likely to bring air
temperatures above 32 deg F. This may delay ongoing river freezing. Residents
are advised to be wary of very thin ice on shallow bodies of water.

FORECASTER: Danny Barandiaran

$$