205
FXUS21 KWNC 231910
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 23 2025
SYNOPSIS: A MAJOR TEMPERATURE CHANGE IS FORECAST FOR ALASKA NEXT WEEK WITH
ANOMALOUSLY COLD TEMPERATURES FORECAST TO PEAK AT THE END OF JANUARY. ARCTIC
HIGH PRESSURE IS THEN EXPECTED TO SHIFT SOUTH TOWARDS THE PACIFIC NORTHWEST,
NORTHERN ROCKIES, AND NORTHERN GREAT PLAINS DURING THE FIRST WEEK OF FEBRUARY.
FROM JANUARY 31-FEBRUARY 2, A LOW PRESSURE SYSTEM MAY TRACK NORTHEASTWARD FROM
THE LOWER MISSISSIPPI VALLEY WITH THE POTENTIAL FOR HEAVY RAINFALL ACROSS THIS
REGION AND A WINTER WEATHER RISK FARTHER NORTH FOR THE CENTRAL APPALACHIANS,
MID-ATLANTIC, AND NORTHEAST. AS A BROAD AREA OF MID-LEVEL LOW PRESSURE EXTENDS
SOUTH INTO THE WEST, THERE IS AN INCREASING CHANCE OF HEAVY SNOW FOR THE
CASCADES AND NORTHERN ROCKIES.
HAZARDS
MODERATE RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR INTERIOR CENTRAL TO
SOUTHWESTERN ALASKA, FRI-SAT, JAN 31-FEB 1.
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR MUCH OF CENTRAL TO SOUTHERN
ALASKA, FRI-MON, JAN 31-FEB 3.
SLIGHT RISK OF HIGH GAP WINDS FOR SOUTHEASTERN ALASKA, SAT-THU, FEB 1-6.
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR THE NORTHERN GREAT PLAINS,
TUE-THU, FEB 4-6.
SLIGHT RISK OF HEAVY SNOW FOR THE CASCADES AND NORTHERN ROCKIES, FRI-THU, JAN
31-FEB 6.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF EASTERN TEXAS, THE LOWER
MISSISSIPPI VALLEY, AND SOUTHEAST, FRI-SAT, JAN 31-FEB 1.
DETAILED SUMMARY
FOR SUNDAY JANUARY 26 - THURSDAY JANUARY 30:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY JANUARY 31 - THURSDAY FEBRUARY 06: MULTI-MODEL ENSEMBLE MEANS
FEATURE A HIGHLY AMPLIFIED RIDGE (TROUGH) OVER THE WESTERN BERING SEA (MAINLAND
ALASKA) DEVELOPING PRIOR TO THE START OF WEEK-2. THIS LONGWAVE PATTERN IS
LIKELY TO PROMOTE CROSS POLAR FLOW INTO ALASKA AND ANOMALOUSLY COLD
TEMPERATURES ARE LIKELY TO BE ONGOING BY JANUARY 31. THE GEFS AND ECENS
PROBABILISTIC EXTREME TOOLS (PETS) DEPICT MINIMUM TEMPERATURES HAVING MORE THAN
A 40 PERCENT CHANCE OF 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 ON JANUARY 31 AND FEBRUARY 1. THE
LATEST MODEL GUIDANCE HAS TRENDED TOWARDS A FASTER MODERATION IN TEMPERATURES
AS THE HIGH AMPLITUDE RIDGE/TROUGH PATTERN SHIFTS EASTWARD EARLIER IN WEEK-2.
THEREFORE, THE SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES WAS DISCONTINUED
AFTER FEBRUARY 3. BEGINNING ON FEBRUARY 1 AND THROUGH THE END OF WEEK-2, THE
GEFS AND ECENS FEATURE ANOMALOUS SURFACE HIGH PRESSURE OVER THE YUKON OF
WESTERN CANADA WHICH SUPPORTS A SLIGHT RISK OF HIGH GAP WINDS FOR SOUTHEASTERN
ALASKA.
BELOW-NORMAL TEMPERATURES ARE LIKELY TO EXPAND SOUTH FROM ALASKA INTO THE
PACIFIC NORTHWEST, NORTHERN ROCKIES, AND NORTHERN GREAT PLAINS AT THE BEGINNING
OF FEBRUARY. SINCE THE GEFS AND ECENS PETS DEPICT MORE THAN A 20 PERCENT CHANCE
OF TEMPERATURES FALLING BELOW -10 DEGREES F WHICH WOULD TRANSLATE TO WIND CHILL
VALUES CLOSE TO COLD ADVISORY CRITERIA, A SLIGHT RISK OF MUCH BELOW-NORMAL
TEMPERATURES IS POSTED FOR THE NORTHERN GREAT PLAINS FROM FEBRUARY 4-6.
THE GEFS AND ECENS REMAIN CONSISTENT THAT THE ANOMALOUS 500-HPA TROUGH
INITIALLY OVER ALASKA EXPANDS SOUTHWARD TO THE PACIFIC NORTHWEST, GREAT BASIN,
AND NORTHERN ROCKIES. BASED ON THE BROAD 500-HPA TROUGH OVER THE WEST, NORTH OF
THE 40TH PARALLEL, PERIODS OF SNOW ARE EXPECTED FOR THE CASCADES AND NORTHERN
ROCKIES. THE DESIGNATED SLIGHT RISK OF HEAVY SNOW WAS GENERALLY SUPPORTED BY
THE GEFS SNOW WATER EQUIVALENT PET AND THE ECENS PROBABILITIES FOR MORE THAN 6
INCHES PER 3-DAY PERIOD. BELOW-NORMAL TEMPERATURES COUPLED WITH LOW PRESSURE
SYSTEMS NEAR THE WEST COAST ELEVATE THE RISK OF FREEZING RAIN AND ACCUMULATING
SNOW FOR THE LOWER ELEVATIONS OF THE PACIFIC NORTHWEST DURING WEEK-2.
UNCERTAINTY ON SNOWFALL AMOUNTS AT THIS TIME RANGE PRECLUDE A DESIGNATION OF A
HEAVY SNOW HAZARD OUTSIDE OF THE CASCADES.
BY JANUARY 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 ON JANUARY 31 AND FEBRUARY 1. MODEL SOLUTIONS REMAIN IN POOR AGREEMENT
AND INCONSISTENT ON THE LOW PRESSURE TRACK ACROSS THE EAST-CENTRAL U.S. EARLY
IN WEEK-2 AND HOW MUCH COLD AIR WOULD PERSIST TO POTENTIALLY SUPPORT SNOW,
SLEET, AND FREEZING RAIN FOR THE CENTRAL APPALACHIANS, MID-ATLANTIC, AND
NORTHEAST FROM JANUARY 31-FEBRUARY 2.
FORECASTER: BRAD PUGH
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