674
FXUS21 KWNC 062009
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 06 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 UNTIL THE MIDDLE OF THE PERIOD,
WITH SANTA ANA WINDS POSSIBLE NEAR THE SOUTHERN CALIFORNIA COAST. MEANWHILE,
EAST OF THE HIGH PRESSURE CENTER, EPISODES OF STRONG DOWNSLOPING WINDS ARE
POSSIBLE IN THE LEE OF THE ROCKIES AND ADJACENT NORTHERN PLAINS THROUGHOUT THE
WEEK. LATE IN THE PERIOD, COLD HIGH PRESSURE MOVING INTO THE EAST BEHIND A COLD
FRONT AND POTENTIAL LOW PRESSURE CENTER INCREASES THE ODDS FOR HIGH WINDS OVER
THE APPALACHIANS AND PORTIONS OF THE NORTHEAST, WITH THE POSSIBILITY OF HEAVY
LAKE-EFFECT SNOW DOWNWIND OF THE EASTERN GREAT LAKES. OUTSIDE THE CONTIGUOUS
UNITED STATES (U.S.), ONE OR MORE POTENTIALLY POTENT STORMS 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. HEAVY PRECIPITATION AND PERIODIC HIGH WIND GUSTS ARE ALSO POSSIBLE
ACROSS HAWAII.
HAZARDS
SLIGHT RISK OF HIGH WINDS IN THE SOUTHWEST FROM ARIZONA THROUGH SOUTHERN
CALIFORNIA, WED-SAT, JAN 14-17
SLIGHT RISK OF HIGH WINDS ALONG THE EAST-CENTRAL AND NORTHEASTERN ROCKIES AND
THE ADJACENT HIGH PLAINS, WED-TUE, JAN 14-20.
SLIGHT RISK OF HIGH WINDS IN PORTIONS OF THE APPALACHIANS AND NORTHEAST,
SUN-TUE, JAN 18-20.
SLIGHT RISK OF HEAVY SNOW IN THE LEE OF LAKES ERIE AND ONTARIO, SUN-TUE, JAN
18-20.
DETAILED SUMMARY
FOR FRIDAY JANUARY 09 - TUESDAY JANUARY 13:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY JANUARY 14 - TUESDAY JANUARY 20: AT THE START OF WEEK-2, MULTIPLE
MODELS FAVOR AN AMPLIFIED PATTERN WITH A SHARP MID-LEVEL TROUGH STRETCHING FROM
WESTERN ALASKA TO THE CENTRAL NORTH PACIFIC, A STRONG DOWNSTREAM MID-LEVEL
RIDGE FROM CENTRAL CANADA THROUGH THE WESTERN CONUS, AND ANOTHER 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 DECAMETER (DM) IN THE PACIFIC NORTHWEST. THE GEFS AND
EUROPEAN ENSEMBLE (ECENS) MEANS ARE WEAKER BY ABOUT 5 DM. OVER THE COURSE OF
WEEK-2, THE AMPLIFIED MID-LEVEL RIDGE OVER THE WESTERN CONUS IS FORECAST TO
RETROGRADE, QUICKLY DISLODGING THE WESTERN ALASKA TROUGH AND ENDING THE PERIOD
WITH THE RIDGE AXIS EXTENDING THE NORTH-CENTRAL PACIFIC THROUGH WESTERN ALASKA.
THE ECENS MEAN IS MOST AMPLIFIED WITH THE RIDGE AT THE END OF WEEK-2, SHOWING
500-HPA HEIGHT ANOMALIES EXCEEDING +30 DM SOUTH OF THE WESTERN ALASKA MAINLAND.
THE GEFS MEAN IS WEAKEST, BUT STILL SHOWS A STRONG FEATURE WITH MID-LEVEL
HEIGHT ANOMALIES EXCEEDING +18 DM FROM THE SOUTHWESTERN ALASKA MAINLAND INTO
THE CENTRAL NORTH PACIFIC. MEANWHILE, DOWNSTREAM FROM THE RIDGE, MID-LEVEL
HEIGHTS STEADILY DROP ACROSS THE WESTERN CONUS. THIS GENERALLY AGREES WITH
MODEL OUTPUT FROM THE PAST FEW DAYS, BUT THERE ARE DIFFERENCES IN HOW THE
PATTERN EVOLVES. MOST MODELS BRING DOWN 500-HPA HEIGHTS MORE SLOWLY THAN
DEPICTED YESTERDAY. THE ENSEMBLE MEANS ALL SHOW NEAR NORMAL HEIGHTS REMAINING
OVER MOST OF THE INTERIOR WEST, WITH POSITIVE HEIGHT ANOMALIES EXCEEDING +6 DM
FROM APPROXIMATELY THE CASCADES WESTWARD. THE GEFS MEAN IS SLOWEST TO KEEP
POSITIVE HEIGHT ANOMALIES LINGERING ACROSS THE INTERIOR WEST, WITH ANOMALIES
STILL EXCEEDING +6 DM THROUGH DAY 12 (SUN JAN 18). THE ECENS MEAN IS QUICKEST
TO LOWER HEIGHTS ACROSS THE WEST, BUT STILL CONSIDERABLY SLOWER THAN YESTERDAY,
CARVING OUT A MODERATELY-AMPLIFIED MID-LEVEL TROUGH FROM SOUTH-CENTRAL CANADA
THROUGH THE INTERIOR WEST BY DAY 13 (MON JAN 19). THE CMCE AND GEFS MEANS SHOW
A SLOWER TRANSITION, KEEPING 500-HPA HEIGHT ANOMALIES OF -3 TO -7 DM OUT OF THE
WESTERN CONUS UNTIL THE END OF WEEK-2. THE ECENS SOLUTION IS FAVORED AT THIS
TIME, SINCE IT IS MORE CONSISTENT WITH YESTERDAY'S MODELS. TO THE SOUTH, ALL
MODELS ARE WEAKER AND FARTHER TO THE SOUTH AND WEST WITH A SECONDARY 500-HPA
TROUGH AND HEIGHT MINIMUM, KEEPING THE FEATURE WELL WEST OF BAJA CALIFORNIA
THROUGHOUT THE PERIOD, THUS REDUCING ITS INFLUENCE ON THE CONUS. FARTHER EAST,
THE ENSEMBLE MEANS ARE SIMILAR TO YESTERDAY IN BUILDING MID-LEVEL HEIGHTS
ACROSS THE SOUTH-CENTRAL AND SOUTHEASTERN CONUS, FORCING THE NEGATIVE ANOMALIES
INITIALLY ALONG THE EAST COAST TO RETREAT NORTHWARD INTO SOUTHERN CANADA AND
THE NORTHEAST. THE MODELS ARE LESS CONSISTENT IN HANDLING THIS EVOLUTION THAN
YESTERDAY. THE ECENS DEPICTS NEGATIVE 500-HPA CENTERED OVER CENTRAL CANADA,
WITH HEIGHTS ONLY SLIGHTLY BELOW NORMAL ACROSS THE NORTHEAST. THE OTHER
ENSEMBLE MEANS ARE MORE CONSISTENT WITH YESTERDAY'S SOLUTIONS; 500-HPA HEIGHT
ANOMALIES END THE PERIOD CENTERED OVER THE NORTHEAST AND ATLANTIC CANADA IN THE
GEFS MEAN, AND NORTH OF THE GREAT LAKES IN THE CMCE MEAN. THE CMCE BEST
RESEMBLES YESTERDAY'S SOLUTIONS, AND IS FAVORED AT THIS TIME.
WEEK-2 STARTS WITH A STRONG SURFACE HIGH PRESSURE SYSTEM CENTERED OVER THE
ROCKIES, IN CONCERT WITH THE AMPLIFIED MID-LEVEL RIDGE THERE. THE DETERMINISTIC
CANADIAN MODEL AND CMCE MEAN ARE STRONGEST WITH THIS FEATURE, SHOWING SURFACE
PRESSURES TOPPING OUT NEAR 1048 MB FROM NORTHEASTERN NEVADA THROUGH THE CENTRAL
ROCKIES. THIS IS LOWER THAN YESTERDAY, BUT STILL SEEMS TOO HIGH. OTHER GUIDANCE
SHOWS SURFACE PRESSURES PEAKING BETWEEN 1035 TO 1040 MB. 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, EXCEEDING 30 PERCENT IN WESTERN ARIZONA AND
SOUTHEASTERN CALIFORNIA. THIS IS A FAVORABLE SETUP FOR SANTA ANA WIND EPISODES,
WHICH SHOWS UP MOST ROBUSTLY IN THE DETERMINISTIC ECMWF, WHICH INDICATES WIND
GUSTS POTENTIALLY APPROACHING 60 MPH NEAR THE SOUTHWESTERN CALIFORNIA MOUNTAINS
NORTH AND EAST OF GREATER LOS ANGELES. FORTUNATELY, THE RECENT WETNESS THERE
SHOULD QUELL ANY SIGNIFICANT INCREASE IN FIRE DANGER. THE BOTTOM LINE IS THAT
THESE FACTORS SUPPORT A SLIGHT RISK OF HIGH WINDS EXTENDING FROM ARIZONA TO THE
SOUTHERN CALIFORNIA COAST THROUGH MID-WEEK, WHEN HIGH PRESSURE OVER THE ROCKIES
IS EXPECTED TO WEAKEN AND DRIFT NORTHWARD, REDUCING THE PRESSURE GRADIENT.
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. FURTHERMORE, THE POTENTIAL FOR A SURFACE LOW
PRESSURE SYSTEM MOVING THROUGH THE NORTHERN PLAINS AROUND MIDWEEK BRINGS
INCREASED CHANCES FOR HIGH WINDS FARTHER EAST ACROSS THE NORTHERN PLAINS, WHICH
WAS NOT EVIDENT IN MOST MODELS YESTERDAY. THE STRENGTH AND DURATION OF
DOWNSLOPING WINDS ARE UNCERTAIN, WITH SEVERAL MODELS INDICATING THE HIGHEST
RISK OCCURRING BOTH EARLY AND LATE WEEK-2, BEST DEPICTED BY THE DETERMINISTIC
ECMWF RAW OUTPUT, AND THE ECENS PET. THE ECENS PET SHOWS CHANCES OVER 50
PERCENT FOR WINDS TO EXCEED THE HAZARDS THRESHOLD (ABOVE THE 15TH PERCENTILE OF
THE CLIMATOLOGICAL ENVELOPE) EARLY WEEK-2, WITH LOWER BUT STILL ELEVATED ODDS
DEPICTED BY THE CMCE AND GFS PETS. ELEVATED ODDS OF HIGH WINDS PERSIST THROUGH
THE WEEK IN THE ECENS AND CMCE PETS, THOUGH THE TIMING OF THE HIGHEST RISK IS
INCONSISTENT PAST THE FIRST FEW DAYS OF THE PERIOD. FOR THESE REASONS, A SLIGHT
RISK OF HIGH WINDS IS POSTED FOR THE LEE OF THE NORTHERN AND CENTRAL ROCKIES,
EXTENDING EASTWARD INTO THE NORTHERN GREAT PLAINS, FOR ALL OF WEEK-2, ALTHOUGH
HIGH WINDS AREN'T EXPECTED TO BE CONTINUOUS THROUGH THE PERIOD.
TODAY'S MODELS SHOW POSITIVE 500-HPA HEIGHT ANOMALIES LINGERING OVER THE
WESTERN CONUS LONGER THAN YESTERDAY, WITH APPRECIABLY BELOW-NORMAL HEIGHTS NOT
APPEARING UNTIL THE END OF WEEK-2 IN THE GEFS AND CMCE MEANS. IN ADDITION, THE
SECONDARY NEGATIVE HEIGHT ANOMALY FARTHER SOUTH, CENTERED OVER OR JUST WEST OF
THE SOUTHWESTERN CONUS IN YESTERDAY'S GUIDANCE, IS WEAKER AND FARTHER TO THE
SOUTH AND WEST TODAY. THESE NEGATIVE 500-HPA HEIGHT FEATURES SUPPORTED A SLIGHT
RISK OF HEAVY SNOW OVER THE HIGH PLAINS YESTERDAY, BUT WITH TODAY'S WEAKER AND
LESS INFLUENTIAL MODEL FORECASTS, THE SLIGHT RISK OF HEAVY SNOW HAS BEEN
REMOVED.
ALMOST ALL OF TODAY'S DETERMINISTIC AND ENSEMBLE MEAN GUIDANCE SHOWS A COLD
FRONT MOVING THROUGH THE EASTERN CONUS LATE WEEK-2, FOLLOWED BY A STRONG, COLD
HIGH PRESSURE SYSTEM.
OVER THE PAST FEW CYCLES OF MODEL RUNS, SOME DETERMINISTIC SOLUTIONS AND
ENSEMBLE MEMBERS HAVE SHOWN CYCLOGENESIS NEAR OR OFFSHORE FROM THE MID-ATLANTIC
OR NORTHEASTERN CONUS AS THE COLD FRONT MOVES INTO THE ATLANTIC. THIS INCREASES
THE ODDS OF A SHARP PRESSURE GRADIENT DEVELOPING BETWEEN THE ADVANCING COLD
HIGH PRESSURE TO THE WEST AND SURFACE LOW PRESSURE TO THE EAST, WHICH MAY
STRENGTHEN AND LINGER NEAR ATLANTIC CANADA. THIS CHAIN OF EVENTS OFTEN BRINGS
HIGH WINDS TO PARTS OF THE EAST-CENTRAL AND NORTHEASTERN CONUS, AND NOW SEVERAL
MODELS, INCLUDING THE DETERMINISTIC ECMWF, SHOW WIND GUSTS EXCEEDING TROPICAL
STORM FORCE FOR BRIEF PERIODS LATER WEEK-2 OVER PORTIONS OF THE APPALACHIANS
AND ACROSS THE NORTHEASTERN CONUS. THEREFORE, A SLIGHT RISK OF HIGH WINDS IS
POSTED FOR LATE WEEK-2 ALONG THE APPALACHIANS AND ACROSS THE NORTHEASTERN
CONUS.
THERE ARE NO HAZARDS POSTED FOR ALASKA AGAIN TODAY. 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 KEEPS CONDITIONS BELOW HAZARDS
THRESHOLDS. A SHARP MID-LEVEL TROUGH INITIALLY ALONG THE WESTERN TIER OF THE
STATE IS RAPIDLY EJECTED BY A STRONG 500-HPA RIDGE BUILDING IN FROM THE
SOUTHEAST. A FEW DETERMINISTIC MODELS SHOW TEMPERATURES 20-30 DEG. F BELOW
NORMAL TO START WEEK-2 IN THE SOUTHWESTERN MAINLAND, BUT THE TOOLS HAVE
PREDOMINANTLY WARMED UP A BIT RELATIVE TO YESTERDAY, AND FEW FORECAST
TEMPERATURES BELOW HAZARDS THRESHOLDS.
THERE IS SOME POTENTIAL FOR ONE OR MORE POTENT STORM SYSTEMS TO AFFECT PARTS OF
SOUTHERN ALASKA. MOST MODEL SOLUTIONS INDICATE LOW SURFACE PRESSURE STARTING
THE WEEK OVER THE NORTHERN GULF OF ALASKA OR RIGHT ALONG THE SOUTH-CENTRAL
ALASKAN COAST, AND A FEW DEPICT A SECOND SYSTEM IMPACTING THE REGION LATER
WEEK-2. THERE IS A LITTLE MORE MODEL SUPPORT FOR STORMY WEATHER THAN YESTERDAY,
PARTICULARLY IN THE ENSEMBLE PETS FOR HIGH WINDS, BUT WHILE MANY MODELS SHOW
PRECIPITATION, SNOWFALL, AND WINDS CONSIDERABLY ABOVE NORMAL AT TIMES, FEW
EXCEED HAZARDS THRESHOLDS. THUS, NOTHING IS POSTED IN ASSOCIATION WITH ANY
STORMS AFFECTING SOUTH-CENTRAL AND SOUTHEASTERN ALASKA AT THIS TIME.
SOME POTENTIAL EXISTS FOR HEAVY PRECIPITATION AND HIGH WINDS ACROSS HAWAII.
THERE IS CONSIDERABLE UNCERTAINTY REGARDING THE LOCATION, EVOLUTION, AND
MAGNITUDE OF ANY HAZARDOUS CONDITIONS, BUT THERE IS GENERAL AGREEMENT THAT
PRECIPITATION OVER MOST OF THE STATE WILL BE WELL ABOVE NORMAL IN SUM FOR
WEEK-2, WITH THE DETERMINISTIC GFS SHOWING THE BEST CHANCES FOR HEAVY
PRECIPITATION IN CENTRAL AND WESTERN PARTS OF THE STATE, AND THE DETERMINISTIC
ECMWF FAVORING AREAS FARTHER EAST. IN ANY CASE, THESE AND MOST OTHER MODELS
HIGHLIGHT THE POTENTIAL FOR A COUPLE OF EPISODES OF HEAVY PRECIPITATION AND
HIGH WINDS IN ASSOCIATION WITH FRONTAL BOUNDARIES MOVING THROUGH AND
POTENTIALLY LINGERING OVER THE ISLAND CHAIN. PETS ARE IN GENERAL AGREEMENT
SHOWING SOMEWHAT INCREASED ODDS FOR HEAVY PRECIPITATION, AND PERIODIC STRONG
WIND GUSTS ARE NOTED IN THE DETERMINISTIC ECMWF AND GFS MODELS. MODEL SOLUTIONS
GENERALLY SHOW PRECIPITATION TOTALING 2 TO 5 INCHES ABOVE NORMAL AT LOWER
ELEVATIONS ACROSS THE STATE, BUT CONSIDERABLY MORE MAY BE RECORDED AT ISOLATED
LOCATIONS.
FORECASTER: RICH TINKER
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