077
FXUS21 KWNC 252006
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST DECEMBER 25 2025
SYNOPSIS: CONTINUED MID-LEVEL HIGH PRESSURE OVER EASTERN SIBERIA AND MID-LEVEL
LOW PRESSURE OVER THE GULF OF ALASKA IS FAVORED TO KEEP VERY COLD AIR IN PLACE
OVER MUCH OF ALASKA, WHILE STRONG PRESSURE CONTRASTS AT THE SURFACE BETWEEN THE
WARMER OCEAN AND THE FRIGID INTERIOR PROMOTE STRONG WINDS ALONG THE SOUTHERN
AND SOUTHEASTERN COAST OF ALASKA. MOIST ONSHORE FLOW PERSISTS OVER THE WEST
COAST, BRINGING POTENTIALLY HEAVY RAIN AND SNOW AND HIGH WINDS TO MUCH OF THE
WESTERN CONTIGUOUS U.S. (CONUS). EARLY IN WEEK-2 A SURFACE LOW PRESSURE SYSTEM
IS FAVORED TO MOVE OVER NEW ENGLAND, USHERING IN POTENTIALLY HAZARDOUS COLD
CONDITIONS.
HAZARDS
MODERATE RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR SOUTHERN ALASKA, THE
CENTRAL AND EASTERN INTERIOR, THE ALASKAN PENINSULA, AND THE NORTHERN
PANHANDLE, FRI-TUE, JAN 2-6.
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR ALL OF ALASKA WITH THE
EXCEPTION OF THE NORTH SLOPE, FRI-THU, JAN 2-8.
SLIGHT RISK OF HIGH WINDS FOR THE ALASKA PENINSULA, SOUTHERN MAINLAND ALASKA,
AND SOUTHEASTERN ALASKA, FRI-THU, JAN 2-8.
SLIGHT RISK OF HEAVY SNOW FOR THE SOUTHERN AND CENTRAL SIERRA NEVADAS, FRI-SUN,
JAN 2-4.
SLIGHT RISK OF HEAVY SNOW FOR THE CASCADES, KLAMATH, AND NORTHERN SIERRA
NEVADAS, SUN-TUE, JAN 4-6.
SLIGHT RISK OF HEAVY SNOW FOR THE NORTHERN ROCKIES, SUN-TUE, JAN 4-6.
SLIGHT RISK OF HEAVY PRECIPITATION FOR CALIFORNIA SOUTH OF SAN FRANCISCO BAY
AND MUCH OF THE DESERT SOUTHWEST, FRI-SUN, JAN 2-4.
SLIGHT RISK OF HEAVY PRECIPITATION FOR NORTHERN CALIFORNIA, AND WESTERN OREGON
AND WASHINGTON, SUN-TUE, JAN 4-6.
SLIGHT RISK OF HIGH WINDS ALONG THE CALIFORNIA COAST SOUTH OF CAPE MEDONCINO,
FRI-SUN, JAN 2-4.
SLIGHT RISK OF HIGH WINDS FOR WESTERN PORTIONS OF THE SOUTHERN AND CENTRAL
PLAINS, FRI-SUN, JAN 2-4.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE NORTHEAST,
FRI-SAT, JAN 2-3.
DETAILED SUMMARY
FOR SUNDAY DECEMBER 28 - THURSDAY JANUARY 01:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY JANUARY 02 - THURSDAY JANUARY 08: TODAY’S MODEL SOLUTIONS ARE IN
RATHER POOR AGREEMENT REGARDING THE SYNOPTIC PATTERN AS DEPICTED BY 500-HPA
HEIGHT ANOMALIES OVER THE NORTH PACIFIC AND NORTH AMERICA, WITH EVER-INCREASING
MODEL SPREAD RELATING TO THE PLACEMENT OF KEY SYNOPTIC FEATURES AS THE FORECAST
PERIOD PROGRESSES. EARLY IN WEEK-2 ENSEMBLE SOLUTIONS DEPICT AMPLIFIED RIDGING
OVER THE BERING SEA, TROUGHING OVER THE WEST COAST, WEAK RIDGING OVER THE
MISSISSIPPI VALLEY, AND AMPLIFIED TROUGHING OVER THE CANADIAN MARITIMES. MODELS
THEN DIVERGE QUICKLY, WITH THE GEFS MAINTAINING A STRONG RIDGE OVER THE BERING
SEA WHILE THE ECWMF AND CMCE FAVOR A WEAKER RIDGE SHIFTED SOUTHWARD INTO THE
NORTH PACIFIC, AND THERE IS NO CONSENSUS WITH REGARD TO THE EVOLUTION OF THE
DOWNSTREAM TROUGH. AS SUCH, FORECAST CONFIDENCE IS RATHER LOW AND RELIES TO
SOME EXTENT ON PERSISTENCE.
AT THE SURFACE, HIGH PRESSURE PERSISTS ACROSS MUCH OF ALASKA AND THE YUKON
THROUGHOUT WEEK-2. CONVERSELY, MEAN LOW PRESSURE IS FAVORED IN THE GULF OF
ALASKA. THE PRESSURE GRADIENT BETWEEN THESE FEATURES BRINGS INCREASED CHANCES
FOR EPISODES OF HIGH WINDS ACROSS MUCH OF SOUTHERN ALASKA FROM THE CENTRAL
ALEUTIAN ISLANDS THROUGH SOUTHEAST ALASKA. HIGH WINDS WOULD BE PARTICULARLY
FAVORED IN GAPS AND INLETS. PROBABILISTIC EXTREMES TOOLS (PETS) SHOW ENHANCED
CHANCES OF WIND SPEEDS EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE. THEREFORE,
A SLIGHT RISK OF HIGH WINDS IS POSTED FOR MOST OF SOUTHERN AND SOUTHEASTERN
ALASKA FOR ALL OF WEEK-2.
PETS CONTINUE TO HIGHLIGHT ENHANCED CHANCES FOR TEMPERATURES TO FALL TO NEAR
HAZARDOUS THRESHOLDS ACROSS MUCH OF SOUTHERN, INTERIOR, AND SOUTHEAST ALASKA,
DRIVEN IN PART BY THE PRESSURE GRADIENT DISCUSSED ABOVE. A MODERATE RISK OF
MUCH BELOW-NORMAL TEMPERATURES IS POSTED FOR SOUTHERN ALASKA, THE CENTRAL AND
EASTERN INTERIOR, THE ALASKAN PENINSULA, AND THE NORTHERN PANHANDLE VALID JAN
2-6, WHILE A BROADER SLIGHT RISK IS POSTED FOR ALL OF ALASKA WITH THE WHILE THE
SOUTHERN HALF OF EXCEPTION OF THE NORTH SLOPE FOR ALL OF WEEK-2. TEMPERATURES
BETWEEN -20 DEG F AND -35 DEG F ARE PREDICTED TO BE WIDESPREAD ACROSS MUCH OF
INLAND ALASKA, WITH -40 DEG F TEMPERATURES INDICATED BY THE PETS OVER THE
EASTERN INTERIOR TO THE NORTH OF FAIRBANKS. CLOSER TO THE COAST, TEMPERATURES
ARE EXPECTED TO RANGE BETWEEN 0 AND -15 DEG F (ANCHORAGE NEAR -10 DEG F),
SOUTHEAST ALASKA IS PREDICTED TO BE SOMEWHAT MILDER, WITH HIGH TEMPERATURES
ABOUT +10 DEG F. THE COMBINATION OF VERY COLD WEATHER AND HIGH WINDS ALONG THE
SOUTHERN TIER OF THE STATE INCREASES THE THREAT FOR HEAVY FREEZING SPRAY AT
TIMES NEAR LARGER BODIES OF WATER.
THE 0Z ECENS, 0Z GEFS, AND 0Z CMCE MODEL SOLUTIONS DEPICT PERSISTENT MID-LEVEL
TROUGHING OVER THE NORTH PACIFIC THROUGHOUT THE FORECAST PERIOD. THE INTEGRATED
VAPOR TRANSPORT (IVT) TOOL ALSO INDICATES MODERATE LOW-LEVEL MOISTURE STREAMING
INTO THE WEST COAST THROUGHOUT THE FORECAST PERIOD, WITH BOTH THE ECMWF AND
GEFS SHOWING PROBABILITIES ABOVE 40% FOR MUCH OF THE WEEK FOR IVT TO EXCEED 150
KG/M/S. TODAY’S FORECAST SOLUTIONS INITIALLY PLACE THE HEAVIEST PRECIPITATION
OVER THE SOUTHWESTERN CONUS, THEN GRADUALLY SHIFT BACK NORTH OVER THE PACIFIC
NORTHWEST. THE PETS AND UNCALIBRATED PRECIPITATION GUIDANCE SUPPORTS A SLIGHT
RISK OF HEAVY PRECIPITATION FOR CALIFORNIA SOUTH OF THE GOLDEN GATE AS WELL AS
MUCH OF THE DESERT SOUTHWEST FOR JAN 2-4, AS WELL AS A SLIGHT RISK FOR NORTHERN
CALIFORNIA, AND WESTERN OREGON AND WASHINGTON FOR JAN 4-6.
THE INCOMING MOISTURE ASSOCIATED WITH THIS ATMOSPHERIC RIVER IS LIKELY TO PUSH
WELL INLAND, RESULTING IN POTENTIALLY HEAVY SNOW FOR MANY MOUNTAIN RANGES
ACROSS THE WEST. UNCALIBRATED PROBABILITIES FROM BOTH THE ECENS AND GEFS FOR
DAILY ACCUMULATIONS OF OVER 6 INCHES EXCEED 40% IN SOME LOCATIONS THROUGHOUT
THE WEEK, AND THE GEFS PET FOR SNOW WATER EQUIVALENT (SWE) INDICATES AT LEAST A
20% CHANCE OF 3-DAY SWE TO EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND AT
LEAST 1 INCH FOR MUCH OF THE CASCADES, SIERRAS, AND NORTHERN ROCKIES DURING
VARIOUS PORTIONS OF WEEK-2. BASED ON THE GEFS PET AND UNCALIBRATED DAILY
SNOWFALL TOTALS, A SLIGHT RISK OF HEAVY SNOW IS POSTED FOR JAN 2-4 COVERING THE
SOUTHERN AND CENTRAL SIERRA NEVADAS, AND JAN 4-6 FOR THE CASCADES, KLAMATH, AND
NORTHERN SIERRAS. FURTHER EAST, A SLIGHT RISK OF HEAVY SNOW IS POSTED FOR MUCH
OF THE NORTHERN ROCKIES VALID JAN 4-6.
ALONG WITH HEAVY PRECIPITATION AND SNOW, HIGH WINDS REACHING HAZARDOUS CRITERIA
ARE ALSO POSSIBLE ASSOCIATED WITH THIS ATMOSPHERIC RIVER (AR) EVENT. MODEL
ENSEMBLE MAXIMUM WIND SPEEDS FROM THE ECMWF AND GEFS EXCEED 20MPH ALONG THE
CALIFORNIA COAST SOUTH OF CAPE MENDOCINO DURING THE FIRST HALF OF WEEK-2,
WARRANTING A SLIGHT RISK OF HIGH WIND ALONG THE COAST COVERING THE PERIOD JAN
2-4. FURTHER INLAND, SURFACE LOW PRESSURE IN THE LEE OF THE ROCKIES EARLY IN
THE FORECAST PERIOD IS FAVORED TO ENHANCE WINDS OVER PORTIONS OF THE GREAT
PLAINS. BASED ON ENSEMBLE MEAN WIND SPEEDS FROM THE GEFS AND ECMWF, A SLIGHT
RISK OF HIGH WINDS IS POSTED FOR WESTERN PORTIONS OF THE SOUTHERN AND CENTRAL
PLAINS, ALSO FOR JAN 2-4. GIVEN A LACK OF ANTECEDENT RAIN AND/OR SNOW, FUELS
ARE UNUSUALLY DRY, ELEVATING THE POTENTIAL FOR PRAIRIE FIRES.
EARLY IN WEEK-2 A DEEP TROUGH IS DEPICTED OVER THE NORTHEAST U.S., RESULTING IN
STRONG NORTHWESTERLY FLOW AND COLDER TEMPERATURES ACROSS THE REGION. PETS FOR
MINIMUM TEMPERATURES INDICATE AT LEAST A 20% CHANCE OF TEMPERATURES FALLING
BELOW -10F ACROSS NORTHERN NEW ENGLAND DURING THE FIRST HALF OF WEEK-2. WHEN
PAIRED WITH ENHANCED WINDS, APPARENT TEMPERATURES MAY FALL BELOW HAZARDOUS
THRESHOLDS WHERE THESE TWO FACTORS COMBINE, THEREFORE A SLIGHT RISK OF MUCH
BELOW-NORMAL TEMPERATURES IS POSTED FOR NON-COASTAL PORTIONS OF NORTHERN NEW
ENGLAND FOR JAN 2-4.
FORECASTER: DANNY BARANDIARAN
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