321
FXUS21 KWNC 111823
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT October 11 2025

SYNOPSIS: A progressive pattern leading to more mid-level low pressure over the
western and central contiguous U.S (CONUS) is expected to bring increased
chances of high elevation heavy snowfall and high winds over the Interior West,
with heavy precipitation possible for portions of the Ohio Valley and Southeast
during week-2. Rising mid-level pressure over the northeastern CONUS is
expected to quell any remaining high winds over the Northeast. A Rapid Onset
Drought risk remains for parts of the Southern Plains and the Lower Mississippi
Valley where above-normal temperatures and limited precipitation remain
forecast during the next week. A stormy pattern forecast over Alaska is
expected to bring potentially heavy precipitation and high winds for most
southern parts of the state.

HAZARDS

Slight risk of heavy precipitation for portions of the Ohio and Tennessee
Valleys, and Southeast, Sun-Mon, Oct 19-20.

Slight risk of heavy snow across the higher elevations of the Central and
Northern Rockies, and adjacent parts of the Great Basin and Great Plains,
Sun-Tue, Oct 19-21.

Slight risk of high winds for many parts of the Interior West and High Plains,
Sat-Tue, Oct 19-21.

Slight risk of high winds for Aleutians, southern Mainland, and parts of
Southeast Alaska, Sun-Thu, Oct 19-23.

Slight risk of heavy precipitation for the southern Mainland, and parts of
Southeast Alaska, Sun-Thu, Oct 19-23.

Rapid Onset Drought (ROD) risk for portions of the Southern Plains and the
Lower Mississippi Valley.

DETAILED SUMMARY

FOR TUESDAY OCTOBER 14 - SATURDAY OCTOBER 18:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR SUNDAY OCTOBER 19 - SATURDAY OCTOBER 25: The mean week-2 500-hPa height
anomalies across the contiguous U.S. (CONUS) are forecast to be relatively
zonal by most of the guidance. An anomalous trough is forecast over the Bering
Sea, bringing enhanced onshore flow into southern Alaska and British Columbia,
with some tools bringing this enhanced flow into the Pacific Northwest as well.
A weak negative North Atlantic Oscillation (-NAO) is favored by the forecast
guidance, but tools have substantially backed off on the -NAO signal relative
to yesterday.



However, the daily progression of this pattern is more amplified relative to
the week-2 mean. A robust wave train is forecast in the tools for the period,
with week-2 starting out with positive anomalies across the northeastern
Pacific, East Coast of the CONUS and Greenland, with negative anomalies over
the Bering Sea, much of the northwestern and central CONUS, and off the East
Coast. The pattern generally flattens and then becomes more amplified again by
the second half of week-2, but with positive anomalies across the West and
negative anomalies over the Great Lakes and Northeast. Negative 500-hPa height
anomalies remain robust over the Bering Sea, but do expand into the Gulf of
Alaska over time.



The most confident forecast area is in Alaska, where there is strong agreement
on a robust mid-level trough and associated surface low pressure. Forecast
guidance supports increased chances for one or more surface low pressure
systems to track into the Bering Sea and/or the Gulf of Alaska. There remains a
wide degree of uncertainty on the exact track of any surface low pressure but
confidence is fairly high for something to develop. Therefore, a broad slight
risk of high winds is forecast across the Aleutians, Alaska Peninsula, and
along the Southern Mainland for Oct 19-23. A corresponding slight risk of heavy
precipitation is forecast for parts of southern Mainland Alaska, from Prince
William Sound to around Yakutat, for the same period.



Across the western CONUS, mid-level troughing may bring more unsettled weather
along with colder temperatures, overspreading the western CONUS, tied to the
prevailing northwesterly flow. Although these temperatures are not expected to
reach hazards criteria following first autumn freezes, the combination of
enhanced tropospheric moisture and anomalous cold does support the potential
for accumulating snowfall across the higher elevations of the West. Based on
the Snow Water Equivalent (SWE) PET from the GEFS, which depicts increased
chances for values exceeding the 85th percentile just ahead of the mean trough
axis, a slight risk of heavy snow is issued for portions of the Central and
Northern Rockies for Oct 19-21. Accompanying this snow hazard, a slight risk of
high winds is also issued, covering a broader area where the ECMWF PET
indicates 20-30% chances for wind speeds exceeding the 85th percentile.



In the central and eastern CONUS the uncertainty is relatively high, with
forecast guidance substantially different relative to prior forecasts. Whereas
yesterday, the ECENS and GEFS were supportive of surface low development over
the Plains, today tools are more supportive of a stronger frontal system
progressing through the Ohio and Tennessee Valleys and Southeast. The
Probabilistic Extremes Tools from the GEFS and ECENS would support a broad
slight risk of heavy precipitation over much of the Southeast and into the Ohio
Valley, with enhanced probabilities of 3-day precipitation amounts exceeding
the 85th percentile and 1 inch. However, raw guidance is faster with the
progression of the frontal system and with a correspondingly reduced amount of
precipitation.



Based on the convergence of the raw model guidance and the PETs, a slight risk
of heavy precipitation is posted for parts of the Ohio and Tennessee Valleys
for Oct 19-20. The precipitation hazard excludes areas of the Southeast where
there are areas currently experiencing abnormal dryness to moderate drought.
These areas are where the GEFS and ECENS PETs have slightly more robust
probabilities of 3-day precipitation amounts exceeding the 85th percentile and
1 inch. However, in these areas 1-2 inches of precipitation may be more
beneficial rather than hazardous at this time. Should forecast precipitation
amounts increase, a precipitation hazard may be warranted and will continue to
be monitored.



A Rapid Onset Drought (ROD) risk remains in effect for many parts of the
Southern Plains and Lower Mississippi Valley where precipitation deficits over
the last 30 days range from 3 to 5 inches, and little precipitation and above
normal temperatures are favored during week-1. Any precipitation that does fall
within the highlighted ROD during week-2 doesn`t appear likely to overcome the
precipitation and soil moisture deficits registered at this time. The ensemble
means for week-2 indicate less than an inch of precipitation at this time.
Should precipitation amounts increase during week-2 a discontinuation of the
ROD shape would be considered.

FORECASTER: Ryan Bolt

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