135
FXUS21 KWNC 221905
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EST January 22 2025

SYNOPSIS: A major temperature change is forecast for Alaska by the end of
January with an increased chance of much below-normal temperatures. The
anomalous cold across Alaska may begin to shift towards the Pacific Northwest,
northern Rockies, and northern Great Plains during the first week of February.
A lower risk of a widespread winter storm is expected through the early part of
week-2 due to a zonal flow pattern. However, there are signs that a more stormy
pattern may develop later in this outlook period as mid-level low pressure
expands southward into the west-central U.S.

HAZARDS

Moderate risk of much below-normal temperatures for interior central to
southwestern Alaska, Thu-Sat, Jan 30-Feb 1.

Slight risk of much below-normal temperatures for much of central to southern
Alaska, Thu-Wed, Jan 30-Feb 5.

Slight risk of much below-normal temperatures for New England and parts of New
York, Thu-Fri, Jan 30-31.

Slight risk of heavy snow for the northern Cascades and northern Rockies,
Thu-Wed, Jan 30-Feb 5.

Slight risk of heavy precipitation for parts of eastern Texas, the lower
Mississippi Valley, and Southeast, Thu-Fri, Jan 30-31.

DETAILED SUMMARY

FOR SATURDAY JANUARY 25 - WEDNESDAY JANUARY 29:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR THURSDAY JANUARY 30 - WEDNESDAY FEBRUARY 05: Multi-model ensemble means
feature a highly amplified ridge (trough) over the western Bering Sea (Mainland
Alaska) developing by the beginning of week-2, January 30. This longwave
pattern is likely to promote cross polar flow into Alaska with the GEFS and
ECENS having the anomalous cold peaking from January 30-February 1 when daily
temperatures are forecast to average near -25 degrees F below normal across
interior Alaska. The GEFS and ECENS Probabilistic Extreme Tools (PETs) depict
minimum temperatures having more than a 40 percent chance of minimum
temperatures falling below the 15th percentile and below -20 degrees F, which
supports a moderate risk of much below-normal temperatures for interior central
to southwestern Alaska from January 30-February 1. A broader slight risk of
much below-normal temperatures, valid for the entirety of week-2, extends as
far south as Anchorage and the Alaska Peninsula. A strong surface high centered
over northeastern Siberia coupled with a surface low across the Gulf of Alaska
is expected to result in enhanced northerly winds especially at the beginning
of week-2. These enhanced winds may cause wind chill values to exceed the cold
advisory criteria of -40F and -55F across southern and central Alaska,
respectively.



Prior to week-2, the ensemble means depict a 500-hPa trough amplifying over
southeastern Canada and the northeastern CONUS which is likely to promote
another surge of Arctic air. A slight risk of much below-normal temperatures,
valid January 30-31, is posted for parts of New York and New England where the
GEFS and ECENS depict minimum temperatures having a 20 percent chance of
falling below the 15th percentile and below -10 degrees F. Gusty northwest
winds could lead to wind chill values below -20 degrees F in the designated
temperature hazard. By the beginning of February, temperatures are forecast to
moderate as the anomalous 500-hPa trough shifts eastward.



The GEFS and ECENS remain consistent that the anomalous 500-hPa trough
initially over Alaska expands southward to the Pacific Northwest and northern
Rockies. Due a model trend towards lower 500-hPa heights, the slight risk of
heavy snow was expanded to include the southern Cascades and southward into
western Wyoming. The slight risk of heavy snow is consistent with where the
GEFS PET has a 20 percent chance that 3-day Snow Water Equivalent (SWE) totals
exceed the 85th percentile and 1 inch, liquid equivalent.



On January 30 and 31, a shortwave trough is expected to eject from the
Southwest and increase the chance of more than 1 inch of precipitation across
eastern Texas, the lower Mississippi Valley, and Southeast. Given the
antecedent wetness with higher 28-day average streamflow percentiles for parts
of Arkansas, Louisiana, and eastern Texas, a slight risk of heavy precipitation
is posted for these areas. This slight risk area is supported by the GEFS PET.

FORECASTER: Brad Pugh

$$