167
FXUS21 KWNC 172049
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EST November 17 2025

SYNOPSIS: Mid-level low pressure centered over the Interior West at the
beginning of week-2 is predicted to rebuild by the end of week-2. With strong
mid-level high pressure over the higher latitudes of western North America,
this pattern favors cold Arctic air sinking south from the western half of
Canada into the western Contiguous U.S. (CONUS), leading to increased chances
for much below normal temperatures designated for the northwestern and central
CONUS. An increased  risk of heavy snow is anticipated for high elevations
initially for the Cascades shifting to the Rockies and portions of the Plains
along with potentially high winds as the mid-level low pressure shifts
eastward. Ahead of this mid-level low, a front may bring heavy precipitation
amounts to parts of the Lower and Middle Mississippi, Ohio, and Tennessee
Valleys, and Southeast at the beginning of the period.

HAZARDS

Slight risk of much below normal temperatures for parts of the northwestern
CONUS and Great Plains, Wed-Mon, Nov 26-Dec 1.

Slight risk of heavy snow for the Cascades, Thu-Mon, Nov 27-Dec 1.

Slight risk of heavy snow for parts of the Rockies and eastern Colorado,
Tue-Thu, Nov 25-27.

Slight risk of heavy snow for parts of the Northern and Central Plains, Upper
Mississippi valley, and Upper Great Lakes, Tue-Mon, Nov 25-Dec 1.

Slight risk of high winds across the Great Plains, Tue-Sat, Nov 25-29.

Slight risk of heavy precipitation for parts of the Lower and Middle
Mississippi, Ohio, and Tennessee Valleys, and Southeast, Tue-Thu, Nov 25-27.

Possible flooding for the Southern Plains, and Lower Mississippi and Tennessee
Valleys.

DETAILED SUMMARY

FOR THURSDAY NOVEMBER 20 - MONDAY NOVEMBER 24:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR TUESDAY NOVEMBER 25 - MONDAY DECEMBER 01: Early in week-2, an amplified
mid-level ridge over Alaska and northeastern Pacific is expected to contribute
to a deepening mid-level trough downstream over the western CONUS. The greatest
positive 500 hPa anomalies are displaced a bit further north toward the Arctic
compared to yesterday. This translates to the GEFS trough being slightly less
amplified at the onset of week-2, with the trough not digging quite as far
south compared to yesterday. The ECENS and Canadian ensemble means favor a more
amplified solution, comparatively. Reloading of this trough is anticipated
toward the end of the period across the West.



Cold Arctic air is anticipated to sink southward from western Canada by day 9
(Nov 26), initially bringing much below normal temperatures to the Pacific
Northwest, shifting to the central CONUS by the middle of the period. A broad
area of slight risk of much below normal temperatures is highlighted across
parts of the northwestern CONUS and Great Plains from Nov 26 to Dec 1. The GEFS
(ECENS) Probabilistic Extremes Tools (PET) indicates at least a 20% (30%)
chance of minimum temperatures falling to the lowest 15th percentile,
climatologically, with the parts of the Pacific Northwest reaching 28 deg F,
and below 20 deg F across parts of the central CONUS.



A front is predicted ahead of the aforementioned mid-level trough over the
West, with the ensemble guidance from multiple models showing the potential for
surface lows tracking from the Rockies to the Great Lakes. This stormy pattern
may bring increased chances for multiple associated hazards to the central
CONUS. A slight risk of heavy snow is designated for the Rockies and eastern
Colorado, Nov 25-27, followed by a slight risk of heavy snow for the Northern
and Central Plains, Upper Mississippi valley, and Upper Great Lakes for week-2.
Uncalibrated ensembles show increased chances for some of these areas receiving
greater than 4 inches over a 3-day period. There is a potential for the pattern
to be favorable for some areas in the Great Lakes receiving heavy Lake Effect
Snow. However, at this time there is too much uncertainty to highlight a Lake
Effect Snow hazard but will be monitored in upcoming days. With surface high
pressure anticipated over the East adjacent to surface low pressure in the
West, a tight pressure gradient may form across the central CONUS supporting a
slight risk of high winds across the Great Plains Nov 25-29.



As the cold front across the central CONUS progresses eastward, heavy
precipitation is possible across the southeastern CONUS. A slight risk of heavy
precipitation is posted for parts of the Lower and Middle Mississippi, Ohio,
and Tennessee Valleys, and Southeast, Nov 25-27. Multiple PETs indicate 3-day
rainfall totals exceeding the 85th percentile and one inch. A possible flood
shape is also highlighted for the Southern Plains, and Lower Mississippi and
Tennessee Valley.



A weak mid-level shortwave trough is anticipated to form over the northeast
Pacific, with associated surface low pressure forming in the Gulf of Alaska
with a trailing cold front extending to the Pacific Northwest. This may bring
heavy snow to high elevations of the Cascades, Nov 27-Dec 1. Uncalibrated ECENS
guidance shows the possibility of 3-day snowfall accumulations reaching 12
inches in the Cascades.



Amplified mid-level ridging is predicted across much of Alaska, with above
normal temperatures favored for much of the state excluding the southeastern
portion where below normal temperatures are anticipated. Surface low pressure
over the Gulf of Alaska combined with adjacent surface high pressure over
British Columbia may lead to a tight pressure gradient along coastal portions
of south-central and southeastern Alaska. This may support gusty wind in these
coastal areas. However, there is too much uncertainty at this time to designate
a high wind risk.

FORECASTER: Melissa Ou

$$