619
FXUS21 KWNC 311841
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EST December 31 2025

SYNOPSIS: There is better agreement among the model guidance today relative to
the past several days. The ECENS, GEFS, and CMCE, support a mid-level low
pressure moving into the western contiguous U.S. (CONUS) and mid-level high
pressure over the Mississippi Valley at the start of the period. The mid-level
low will continue to move inland bringing increased chances for heavy
precipitation and snow to portions of the East and high wind chances over the
Four Corners region. In Alaska, the mid-level height pattern continues to
evolve bringing warmer surface temperatures into the state by week-2.

HAZARDS

Slight risk of heavy precipitation over portions of the Mississippi, Tennessee,
and Ohio Valleys, and in parts of the Southeast, Thu-Mon, Jan 8-12.

Slight risk of heavy snow over portions of the Northern and Central Plains,
Upper Mississippi Valley, and Great Lakes, Fri-Mon, Jan 9-12.

Slight risk of high winds over portions of the Four Corners and into the
Southern Plains, Thu-Sat, Jan 8-10.

DETAILED SUMMARY

FOR SATURDAY JANUARY 03 - WEDNESDAY JANUARY 07:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR THURSDAY JANUARY 08 - WEDNESDAY JANUARY 14: The evolution of the pattern
following the breakdown of the strong mid-level ridging over the Aleutians and
North Pacific has been very uncertain over the past few days. Today, models
have trended towards each other and there is better agreement between the GEFS,
ECENS, and CMCE regarding the 500-hPa height pattern early in week-2. There
remain differences and confidence remains low but tools have trended towards a
positive 500-hPa height anomaly over the northeastern Pacific and northwestern
North America, a mid-level trough moving inland over the western CONUS, and
positive 500-hPa height anomalies again over eastern North America at the onset
of week-2.



The mid-level trough over the western CONUS enhances chances for high winds
over the Four Corners and western Southern Plains early in the week-2 period.
The ECENS Probabilistic Extremes Tool (PET) is very supportive of these chances
while the GEFS PET is more subdued but in fair agreement over the pattern.
Therefore, a slight risk of high winds is posted for parts of the Four Corners,
Southern Rockies, and into the Southern Plains, Jan 8-10.



The mid-level low and high pressure dipole over the CONUS would support one or
more frontal systems developing over the central and eastern CONUS during
week-2. There remains considerable uncertainty regarding the timing and
location of this system but there is converging evidence for heavy
precipitation to develop over the Middle and Lower Mississippi, Tennessee, and
Ohio Valleys for much of the week-2 period. Uncalibrated probabilities from the
GEFS and ECENS support a 30-40% chance of precipitation exceeding 1 inch over
the 8-10 and 10-12 day periods over the highlighted region. The PETs from all
three ensembles indicate elevated chances for 3 day precipitation amounts to
exceed the 85th percentile as well. Therefore, a slight risk of heavy
precipitation is posted for Jan 8-12.



Across the Northern Plains, Upper Mississippi Valley and Upper Great Lakes,
snow is the most likely precipitation type. The ensemble and deterministic
guidance from the GEFS, ECENS, and their AI counterparts supports the potential
for at least one system to move through the region starting around day 9.
However, there is considerable uncertainty regarding the timing and location of
any winter precipitation. Therefore, a fairly broad area of heavy snow is
highlighted across the north-central CONUS. Some, but not all, of the tools
would support bringing this system into parts of the Northeast, therefore, the
shape does not include the Northeast at this time but will be monitored.



Following these systems, the GEFS supports bringing much below normal
temperatures into the central CONUS. However, the ECENS is not on board with
this solution at this time and probabilities remain very low in the GEFS.
Therefore, no hazard is posted at this time but the potential for hazardous
cold will be watched.



In Alaska, the ECENS continues to have high chances for temperatures to fall
below the 15th climatological percentile over southwestern Mainland Alaska.
However, the temperature pattern is rapidly evolving over Alaska, with much
warmer temperatures, relative to much of December, will be building into
Mainland Alaska. The raw ECENS mean temperature is above-normal by day 8 over
southwestern Mainland and with little support from the other models the slight
risk of much below normal is discontinued.

FORECASTER: Ryan Bolt

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