174
FXUS21 KWNC 051953
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 05 2026
SYNOPSIS: AT THE START OF WEEK-2, A TIGHT GRADIENT BETWEEN HIGH SURFACE
PRESSURE OVER THE INTERIOR WEST AND LOW PRESSURE FARTHER SOUTH INCREASES THE
ODDS FOR PERIODIC HIGH WINDS OVER THE SOUTHWEST THROUGH THE MIDDLE OF THE
PERIOD, WITH SANTA ANA WINDS POSSIBLE NEAR THE SOUTHERN CALIFORNIA COAST.
MEANWHILE, EAST OF THE HIGH PRESSURE CENTER, STRONG DOWNSLOPING WINDS ARE
POSSIBLE IN THE LEE OF THE ROCKIES. LATER IN THE PERIOD, SURFACE HIGH PRESSURE
IS EXPECTED OVER THE CANADIAN PRAIRIES WHILE THE SOUTHERN ROCKIES AND ADJACENT
HIGH PLAINS SEE LOWER PRESSURES. THIS IS FAVORABLE FOR HEAVY SNOW ALONG THE
EASTERN TIER OF THE ROCKIES AND THE WESTERN HIGH PLAINS, WITH UPSLOPING
LOW-LEVEL FLOW ENHANCING TOTALS. FARTHER NORTH, A POTENTIALLY POTENT STORM NEAR
SOUTHERN ALASKA MAY BRING HIGH WINDS AND HEAVY PRECIPITATION TO SOUTH-CENTRAL
AND SOUTHEASTERN ALASKA, BUT THERE IS TOO MUCH UNCERTAINTY TO POST ANY RELATED
HAZARDS.
HAZARDS
SLIGHT RISK OF HIGH WINDS IN THE SOUTHWEST FROM ARIZONA THROUGH SOUTHERN
CALIFORNIA, TUE-SAT, JAN 13-17
SLIGHT RISK OF HIGH WINDS ALONG THE EAST-CENTRAL AND NORTHEASTERN ROCKIES AND
THE ADJACENT HIGH PLAINS, TUE-THU, JAN 13-15.
SLIGHT RISK OF HEAVY SNOW ALONG THE EASTERN TIER OF THE ROCKIES AND THE
ADJACENT HIGH PLAINS, FRI-MON, JAN 16-19.
DETAILED SUMMARY
FOR THURSDAY JANUARY 08 - MONDAY JANUARY 12:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY JANUARY 13 - MONDAY JANUARY 19: EARLY WEEK-2, MULTIPLE MODEL
ENSEMBLE MEANS FAVOR A MODERATELY AMPLIFIED PATTERN WITH A SHARP MID-LEVEL
TROUGH STRETCHING FROM WESTERN ALASKA INTO THE CENTRAL NORTH PACIFIC, A STRONG
DOWNSTREAM MID-LEVEL RIDGE OVER THE WESTERN CONTIGUOUS UNITED STATES (CONUS),
AND A WEAKER MID-LEVEL TROUGH ACROSS THE EASTERN CONUS. THE CANADIAN ENSEMBLE
(CMCE) MEAN INDICATES THE STRONGEST MID-LEVEL RIDGE ACROSS THE WESTERN CONUS,
SHOWING 500-HPA HEIGHT ANOMALIES OVER +24 DM IN THE PACIFIC NORTHWEST, WHILE
THE GEFS AND EUROPEAN ENSEMBLE (ECENS) ARE SOMEWHAT WEAKER BY ABOUT 5 DM. THIS
PATTERN IS ANTICIPATED TO REMAIN IN PLACE WITH SOME AMPLIFICATION OF THE
MID-LEVEL TROUGH OVER THE EASTERN CONUS FOR THE FIRST COUPLE DAYS OF WEEK-2,
FOLLOWED BY RETROGRADING OF THIS FEATURE. BY THE END OF THE PERIOD, THE
ENSEMBLE MEANS SHOW A STRONG MID-LEVEL RIDGE OVER THE UPPER NORTH PACIFIC,
RESULTING IN MID-LEVEL HEIGHTS BUILDING OVER ALASKA, BUT DROPPING OVER THE
WESTERN CONUS. THIS RESULTS IN A RELATIVELY WEAK POSITIVELY-TILTED MID-LEVEL
TROUGH STRETCHING FROM SOUTH-CENTRAL OR SOUTHEASTERN CANADA INTERIOR WEST. THE
CMCE MEAN REMAINS THE STRONGEST WITH THE REPOSITIONED MID-LEVEL RIDGE,
DEPICTING 500-HPA ANOMALIES EXCEEDING +30 DM JUST SOUTH OF THE GULF OF ALASKA.
THE OTHER TWO ENSEMBLE MEANS ARE A BIT WEAKER, WITH THE GEFS MEAN KEEPING
POSITIVE HEIGHT ANOMALIES UNDER +24 DM. A COMPROMISE OF THE 3 ENSEMBLE MEANS IS
FAVORED HERE, ALTHOUGH THE DIFFERENCES WOULDN'T RESULT IN MUCH CHANGE TO THE
SENSIBLE WEATHER. MEANWHILE, THE ENSEMBLE MEANS ALL ESTABLISH A WEAK,
POSITIVELY-TILTED MID-LEVEL TROUGH ACROSS THE WESTERN CONUS THAT EXTENDS INTO
THE PACIFIC OFF THE SOUTHERN CALIFORNIA COAST. THE ECENS AND CMCE ALL DEPICT A
SECONDARY 500-HPA NEGATIVE ANOMALY CENTER IN OR OVER THE SOUTHWEST WHILE THE
GEFS MEAN KEEPS SIGNIFICANT ANOMALIES FARTHER NORTH. THE DETERMINISTIC MODELS
TEND TO FAVOR THE SECONDARY HEIGHT MINIMUM ON THE SOUTHERN EXTENSION OF THE
MID-LEVEL TROUGH, SO THAT SOLUTION IS FAVORED. THE CMCE AND ECENS MEANS WOULD
RESULT IN A PATTERN FAVORING HEAVIER PRECIPITATION OVER AND NEAR THE
SOUTHEASTERN ROCKIES. ACROSS THE EASTERN HALF OF THE CONUS, THE MID-LEVEL
TROUGH IS EXPECTED TO DIMINISH AND RETREAT NORTHWESTWARD LATER IN THE WEEK AS A
FLAT MID-LEVEL RIDGE BECOMES ESTABLISHED ACROSS THE LOWER MISSISSIPPI VALLEY
AND THE SOUTHEAST, ALTHOUGH THIS FEATURE IS WEAKER TODAY THAN YESTERDAY IN MOST
OF THE GUIDANCE. WHILE THE ENSEMBLE MEANS ARE IN DECENT AGREEMENT OVERALL, A
FEW DETERMINISTIC MODEL RUNS SHOW MID-LEVEL FEATURES THAT ARE MORE AMPLIFIED
AND/OR PERSISTENT, INTRODUCING UNCERTAINTY INTO THE WEEK-2 HAZARDS FORECAST.
AT THE START OF WEEK-2, THE MID-LEVEL RIDGE OVER THE INTERIOR WEST IS EXPECTED
TO ESTABLISH A STRONG SURFACE HIGH PRESSURE SYSTEM CENTERED OVER THE ROCKIES.
THE DETERMINISTIC CANADIAN MODEL IS STRONGEST WITH THIS FEATURE, SHOWING
SURFACE PRESSURES TOPPING OUT NEAR 1054 MB FROM NORTHEASTERN NEVADA THROUGH THE
CENTRAL ROCKIES, BUT THIS LOOKS UNREASONABLY HIGH. OTHER GUIDANCE SHOWS SURFACE
PRESSURES PEAKING IN THE 1035 TO 1045 MB RANGE, WHICH IS STILL MUCH HIGHER THAN
USUAL. MEANWHILE, MID-LEVEL HEIGHTS ARE FORECAST TO BE CLOSER TO NORMAL FARTHER
SOUTH TOWARD MEXICO AND THE ADJACENT PACIFIC, RESULTING IN LOWER SURFACE
PRESSURES OVER THE SOUTHWEST. MOST MODEL SOLUTIONS SHOW SURFACE PRESSURES BELOW
1024 MB IN PARTS OF SOUTHERN ARIZONA AND SOUTHERN CALIFORNIA AT THE BEGINNING
OF THE PERIOD. THIS RESULTS IN A TIGHT PRESSURE GRADIENT OVER PORTIONS OF THE
SOUTHWEST, INCREASING THE ODDS FOR PERIODS OF HIGH WINDS ACROSS THE REGION. THE
PROBABILISTIC EXTREMES TOOL (PET) FROM THE ECENS AND CMCE SHOW ELEVATED ODDS
FOR WINDS REACHING THE TOP 15 PERCENT OF CLIMATOLOGY, PEAKING NEAR 35 PERCENT
CHANCES IN PARTS OF ARIZONA EARLY IN THE PERIOD. NEAR COASTAL SOUTHERN
CALIFORNIA, THIS PATTERN COULD RESULT IN PERIODIC SANTA ANA WIND EPISODES.
FORTUNATELY, THE RECENT WETNESS THERE SHOULD SQUELCH ANY SIGNIFICANT INCREASE
IN FIRE DANGER. THE BOTTOM LINE IS THAT THESE FACTORS SUPPORT A SLIGHT RISK OF
HIGH WINDS IN THE SOUTHWEST, WHICH IS POSTED FROM ARIZONA WESTWARD THROUGH THE
SOUTHERN CALIFORNIA COAST UNTIL MID-WEEK, WHEN THE MID-LEVEL RIDGE HAS
RETROGRADED SUFFICIENTLY TO PULL THE SURFACE HIGH PRESSURE NORTHWARD AND
NORTHWESTWARD AWAY FROM THE ROCKIES.
MEANWHILE, ON THE EASTERN SIDE OF THE HIGH SURFACE PRESSURE SYSTEM OVER THE
ROCKIES, A TIGHT PRESSURE GRADIENT WITH SIGNIFICANTLY LOWER PRESSURES JUST TO
THE EAST IN THE CENTRAL AND NORTHERN HIGH PLAINS COULD RESULT IN ONE OR MORE
EPISODES OF STRONG DOWNSLOPING WINDS NEAR THE NORTHERN HALF OF THE FRONT RANGE
AND IN THE ADJACENT HIGH PLAINS. THIS SET-UP IS DEPICTED BY MOST OF THE
GUIDANCE, ALTHOUGH THE STRENGTH AND DURATION OF THESE CONDITIONS ARE
UNCERTAIN.. THE PETS FROM ALL THREE ENSEMBLE MEANS SHOW ELEVATED CHANCES FOR
WINDS TO EXCEED THE UPPER 15 PERCENTILE THRESHOLD OF THE CLIMATOLOGICAL
ENVELOPE, SUPPORTING A SLIGHT RISK OF HIGH WINDS IN THIS REGION FOR THE FIRST
FEW DAYS OF WEEK-2. AS THE SURFACE HIGH PRESSURE RETREATS NORTHWARD AND
NORTHWESTWARD WITH TIME, BOTH THE REDUCED PRESSURE GRADIENT AND THE CHANGE IN
WIND DIRECTION IS EXPECTED TO BRING AN END TO THE HIGH WIND RISK.
LATER IN WEEK-2, 500-HPA HEIGHTS BEGIN TO BUILD A WEAK FLAT RIDGE OVER THE
SOUTH-CENTRAL AND SOUTHEASTERN CONUS, PUSHING THE EASTERN CONUS MID-LEVEL
TROUGH NORTHWARD INTO SOUTHERN CANADA. AT THE SAME TIME, THE MID-LEVEL RIDGE
INITIALLY OVER THE WESTERN CONUS BEGINS TO RETROGRADE, BUILDING TOWARD THE
CENTRAL NORTH PACIFIC AND INTO ALASKA. THIS RESULTS IN LOWERING 500-HPA HEIGHTS
OVER THE WESTERN CONUS, ESTABLISHING AN POSITIVELY-TILTED ANOMALOUS MID-LEVEL
TROUGH WITH AN AXIS REACHING FROM SOUTHERN CANADA THROUGH THE INTERIOR WEST TO
NEAR OR OFF THE CALIFORNIA COAST. THE CMCE AND ECENS MEANS SHOW A WEAK
SECONDARY 500-HPA HEIGHT MINIMUM NEAR THE FAR SOUTHWESTERN CONUS LATER WEEK-2
WHICH RETROGRADES SLIGHTLY AS THE PERIOD ENDS. IN CONCERT WITH THE RETROGRADING
MID-LEVEL RIDGE CENTERED IN THE NORTH PACIFIC TOWARD THE END OF THE PERIOD,
THIS PATTERN IS ANTICIPATED TO ESTABLISH RELATIVELY HIGH SURFACE PRESSURES
ABOVE THE TROUGH AXIS IN THE CANADIAN PRAIRIES, AND LOWER SURFACE PRESSURES
OVER THE SOUTHERN TO CENTRAL HIGH PLAINS UPSTREAM FROM THE SECONDARY 500-HPA
HEIGHT ANOMALY CENTER. THIS PATTERN INCREASES THE LIKELIHOOD OF HEAVY SNOW
ALONG THE FRONT RANGE AND ADJACENT HIGH PLAINS. EASTERLY UPSLOPING LOW LEVEL
FLOW COULD FURTHER ENHANCE SNOWFALL. THE RAW DETERMINISTIC AND ENSEMBLE MEAN
SNOWFALL FORECASTS REMAIN GENERALLY UNREMARKABLE, BUT THE GEFS PET SHOWS
INCREASED ODDS FOR SNOW WATER EQUIVALENT TOTALS AMONG THE TOP 15 PERCENT OF THE
CLIMATOLOGICAL ENVELOPE FOR THE LAST FEW DAYS OF WEEK-2 ALONG THE SOUTHEASTERN
ROCKIES AND ADJACENT HIGH PLAINS. THERE ARE NO SNOW WATER EQUIVALENT PETS
DERIVED FROM EITHER THE ECENS OR CMCE, BUT THE PATTERN FORECAST BY THEIR
ENSEMBLE MEANS WOULD BE MORE FAVORABLE FOR HEAVY SNOW IN THE REGION THAN THE
GEFS MEAN, BOOSTING FORECAST CONFIDENCE SOMEWHAT. DOWNSTREAM FROM THE 500-HPA
HEIGHT MINIMUM NEAR THE SOUTHWESTERN CONUS, THE PETS FROM ALL THREE ENSEMBLES
SHOW SLIGHTLY ELEVATED ODDS FOR PRECIPITATION TOTALS IN THE 85TH PERCENTILE
ACROSS THE SOUTHERN ROCKIES AND SOME ADJACENT AREAS. IN ADDITION, SOME OF THE
DETERMINISTIC MODELS SHOW IMPRESSIVE IF NOT OVERWHELMING PRECIPITATION TOTALS
IN THIS REGION LATER WEEK-2, BUT TOO MUCH UNCERTAINTY REMAINS TO POST ANY
RELATED HAZARDS AT THIS TIME.
THERE ARE NO HAZARDS POSTED FOR ALASKA AGAIN TODAY, BUT SOME MODEL GUIDANCE
SHOWS A LIMITED POTENTIAL FOR A FEW HAZARDS. HOWEVER, THERE IS A GREAT DEAL OF
MODEL SPREAD AND THE PREPONDERANCE OF THE TOOLS KEEP CONDITIONS BELOW HAZARDS
THRESHOLDS. A SHARP MID-LEVEL TROUGH INITIALLY ALONG THE WESTERN TIER OF THE
STATE COULD RESULT IN MUCH BELOW NORMAL TEMPERATURES OVER SOME OF THE CENTRAL
AND WESTERN SECTIONS OF THE MAINLAND. EARLY WEEK-2, SOME DETERMINISTIC MODELS
AND ENSEMBLE MEANS DEPICT TEMPERATURES REACHING 10 TO ALMOST 30 DEG. F BELOW
NORMAL FOR AT LEAST SOME PORTION OF THE WEST-CENTRAL OR SOUTHWESTERN PARTS OF
THE STATE, BUT MOST GUIDANCE HAS WARMED UP A BIT RELATIVE TO YESTERDAY. THE
MOST EXTREME MODEL SOLUTIONS SHOW TEMPERATURE DROPPING AS LOW AS -45 DEG. F
BELOW NORMAL, BUT THE MAJORITY OF THE TOOLS FAVOR MILDER CONDITIONS, WHICH
REPRESENTS A SHIFT TOWARD NORMAL RELATIVE TO YESTERDAY. GIVEN THE WIDE RANGE OF
MODEL SOLUTIONS AND THE SHIFT AWAY FROM EXTREME COLD IN MOST TOOLS, NO RELATED
HAZARDS ARE POSTED AT THIS TIME.
THERE IS ALSO UNCERTAINTY REGARDING THE POTENTIAL FOR A POTENT STORM SYSTEM TO
AFFECT SOME OF THE SOUTHERN PARTS OF ALASKA. MOST MODEL SOLUTIONS INDICATE LOW
SURFACE PRESSURE STARTING THE WEEK OVER OR NEAR THE GULF OF ALASKA WITH HIGHER
SURFACE PRESSURES ACROSS THE INTERIOR OF ALASKA AND WESTERN CANADA. HOWEVER,
THE STRENGTH AND LOCATION OF ANY STORM SYSTEM THAT FORMS AND THE HIGH SURFACE
PRESSURES TO THE NORTH AND EAST ARE HIGHLY UNCERTAIN. THE 0Z DETERMINISTIC
ECMWF DEPICTS A 962 HPA LOW PRESSURE CENTER IN THE GULF OF ALASKA EARLY IN
WEEK-2 WHILE SURFACE PRESSURES APPROACH 1020 HPA IN FAR SOUTHEASTERN ALASKA.
THIS PATTERN WOULD ENGENDER HIGH WINDS AND HEAVY PRECIPITATION ACROSS
SOUTH-CENTRAL AND SOUTHEASTERN ALASKA, ALONG WITH HEAVY SNOWFALL AWAY FROM THE
IMMEDIATE COAST. IN CONTRAST, THE ENSEMBLE MEANS ALL KEEP THE SURFACE LOW
PRESSURE CENTER ABOVE 990 MB, WITH MOST MEMBERS BEING WEAKER THAN DEPICTED
YESTERDAY. IN ADDITION, SEVERAL TOOLS PLACE A RELATIVELY WEAK LOW PRESSURE
CENTER INLAND AT THE START OF WEEK-2, WHICH WOULD BE LESS FAVORABLE FOR
UNSETTLED WEATHER. THE PETS DERIVED FROM THE ECENS AND CMCE SHOW ENHANCED ODDS
FOR WINDS REACHING THE TOP 15TH PERCENTILE, BUT THE RAW WIND FORECASTS FROM THE
ENSEMBLE MEANS AND MOST DETERMINISTIC MODELS KEEP PRECIPITATION AND WINDS BELOW
HAZARDS THRESHOLDS. GIVEN THE BROAD ARRAY OF MODEL SOLUTIONS, NO WIND OR
PRECIPITATION HAZARDS ARE POSTED IN ALASKA AT THIS TIME.
FORECASTER: RICH TINKER
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