481
FXUS21 KWNC 141934
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 14 2025
SYNOPSIS: SURFACE HIGH PRESSURE IS FORECAST ACROSS THE EASTERN CONTIGUOUS U.S.
(CONUS) AT THE OUTSET OF WEEK-2, WITH AN ARCTIC AIR OUTBREAK ONGOING, BUT
BEGINNING TO MODERATE RELATIVE TO THE LATE WEEK-1 PERIOD. MID LEVEL-HIGH
PRESSURE IS PREDICTED OVER THE WEST WITH INCREASING DOWNSLOPE FLOW ACROSS MUCH
OF THE CENTRAL CONUS. THIS FAVORS WARMING TEMPERATURES BUT ALSO AN INCREASED
RISK FOR HIGH WINDS, ESPECIALLY ACROSS THE NORTHERN TIER WHERE PRESSURE
GRADIENTS ARE FORECAST TO BE STRONGEST. MID-LEVEL LOW PRESSURE ACROSS THE
NORTHEAST PACIFIC AND ALASKA FAVORS INTERMITTENT ROUNDS OF ENHANCED
PRECIPITATION ACROSS PORTIONS OF SOUTHEAST ALASKA AND THE NORTHWEST CONUS,
ALTHOUGH HAZARDS THRESHOLDS ARE UNLIKELY TO BE REACHED.
HAZARDS
MODERATE RISK FOR HIGH WINDS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL HIGH
PLAINS, SAT-MON, FEB 22-24.
SLIGHT RISK FOR HIGH WINDS ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS,
UPPER AND MIDDLE MISSISSIPPI VALLEY, AND THE GREAT LAKES, SAT-WED, FEB 22-26.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE GREAT
PLAINS, GREAT LAKES, UPPER AND MIDDLE MISSISSIPPI AND OHIO VALLEYS, AND
NORTHEAST, SAT, FEB 22.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE SOUTHERN
PLAINS, LOWER MISSISSIPPI AND TENNESSEE VALLEYS, SOUTHEAST, APPALACHIANS, AND
MID-ATLANTIC, SAT-SUN, FEB 22-23.
POSSIBLE FLOODING FOR THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS, SOUTHEAST,
AND THE APPALACHIANS.
DETAILED SUMMARY
FOR MONDAY FEBRUARY 17 - FRIDAY FEBRUARY 21:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY FEBRUARY 22 - FRIDAY FEBRUARY 28: A MAJOR ARCTIC AIR OUTBREAK IS
FORECAST TO BE ONGOING ACROSS MUCH OF THE EASTERN HALF OF THE CONUS AT THE
OUTSET OF WEEK-2. THE GEFS (ECENS) PROBABILISTIC EXTREMES TOOL (PETS) DEPICTS
AT LEAST A 40 (60) PERCENT CHANCE MINIMUM TEMPERATURES FALL BELOW THE LOWEST
15TH CLIMATOLOGICAL PERCENTILE ON DAY-8 (FEB 22) FROM THE OHIO AND TENNESSEE
VALLEYS SOUTHWARD TO THE GULF COAST. HOWEVER, DESPITE THESE HIGHER
PROBABILITIES, THE UNCALIBRATED 0Z GEFS AND ECENS INDICATE ABOUT A 5-10 DEG F
RISE IN MINIMUM SURFACE TEMPERATURES BETWEEN DAYS 7 AND 8 (FEB 21 AND 22)
SIGNALING THAT THE MOST ROBUST COLD IS FAVORED LATE IN WEEK-1 AND BEGINNING TO
MODERATE HEADING INTO WEEK-2. THE PERCENTILE PROBABILITIES IN THE PETS ARE
LIKELY INFLATED DUE TO THE RISING TEMPERATURE CLIMATOLOGY IN LATE-FEBRUARY, AND
THE CHANCES FOR ABSOLUTE TEMPERATURES REACHING HAZARDS COLD THRESHOLDS CONTINUE
TO TREND DOWNWARD. WINDS ARE ALSO FORECAST TO BE LIGHTER UNDERNEATH THE SURFACE
HIGH, LIMITING THE WIND CHILL VALUES. THEREFORE, ONLY A SLIGHT RISK FOR MUCH
BELOW NORMAL TEMPERATURES IS POSTED FROM THE GREAT PLAINS EASTWARD TO THE
ATLANTIC COAST. THE RISK IS DISCONTINUED AFTER DAY-8 (FEB 22) ACROSS THE GREAT
PLAINS, UPPER AND MIDDLE MISSISSIPPI AND OHIO VALLEYS, GREAT LAKES, AND
NORTHEAST, AND CONTINUES THROUGH DAY-9 (FEB 23) ACROSS PORTIONS OF THE SOUTHERN
PLAINS, LOWER MISSISSIPPI AND TENNESSEE VALLEYS, GREAT LAKES, MID-ATLANTIC, AND
SOUTHEAST CONSISTENT WITH THE PATTERN PROGRESSION INDICATING WEAKENING SURFACE
HIGH PRESSURE AND INCREASING PACIFIC FLOW SUPPORTING A WEST TO EAST WARMING
TREND.
DURING WEEK-2, AN AREA OF MID-LEVEL LOW PRESSURE ACROSS THE ARCTIC IS FORECAST
TO DROP SOUTHWARD INTO NORTHERN CANADA. THIS FAVORS DECREASING MID-LEVEL
HEIGHTS AND LOWERING SURFACE PRESSURES ACROSS MUCH OF CANADA, WITH A TIGHTENING
PRESSURE GRADIENT EXTENDING INTO THE NORTH-CENTRAL CONUS DUE TO THE SURFACE
HIGH ESTABLISHED OVER THE SOUTHEAST. THIS SET-UP IN COMBINATION WITH A RIDGE
OVER THE WEST FAVORS INCREASING PACIFIC FLOW AND DOWNSLOPE WINDS ACROSS THE
NORTHERN PLAINS INTO THE UPPER MIDWEST. THE ECENS PET DEPICTS PARTS OF THE
NORTHERN HIGH PLAINS HAVING AT LEAST A 40 PERCENT CHANCE WIND SPEEDS EXCEED THE
85TH CLIMATOLOGICAL PERCENTILE, WITH PROBABILITIES ABOVE 30 PERCENT IN THE
GEFS. THERE IS ALSO SUPPORT IN THE UNCALIBRATED GUIDANCE INDICATING INCREASED
CHANCES FOR WIND SPEEDS EXCEEDING 25-MPH JUSTIFYING A MODERATE RISK FOR HIGH
WINDS ACROSS THE NORTHERN AND CENTRAL HIGH PLAINS, FEB 22-24. THE SLIGHT RISK
IS EXTENDED FURTHER EAST TO THE GREAT LAKES THROUGH FEB 26, CONSISTENT WITH
WHERE THE ECENS PET DEPICTS AT LEAST A 20 PERCENT CHANCE WIND SPEEDS EXCEED THE
85TH PERCENTILE AND 20-MPH.
RIDGING AND RELATIVELY DRIER CONDITIONS ARE FAVORED ACROSS THE WESTERN CONUS
DURING WEEK-2, ESPECIALLY OVER MORE SOUTHERN AREAS. WITH THE MEAN FLOW PATTERN
LOOKING TO BECOME MORE OFFSHORE, PORTIONS OF CALIFORNIA MAY SEE RENEWED RISK OF
HIGH WINDS. HOWEVER, THERE REMAINS INSUFFICIENT SUPPORT IN THE TOOLS TO ISSUE
ANY CORRESPONDING WIND HAZARDS, AND GIVEN THE HEAVY PRECIPITATION AND FLOODING
EXPERIENCED OVER THE REGION RECENTLY, THIS PART OF THE COUNTRY LOOKS TO BE LESS
SUSCEPTIBLE TO ANY WILDFIRE RISK. ELEVATED WIND SPEEDS REMAIN POSSIBLE ACROSS
THE NORTHEAST ON DAY-8 (FEB 22) IN THE WAKE OF A DEPARTING SURFACE LOW LATE IN
WEEK-1, ALTHOUGH THE STRONGEST WINDS ARE NOW FAVORED PRIOR TO THE START OF
WEEK-2 ALLOWING THE RELATED WIND HAZARD FROM YESTERDAY TO BE DISCONTINUED.
ALTHOUGH PRECIPITATION GUIDANCE HAS TRENDED CONSIDERABLY DRIER FOR WEEK-2 FOR
MUCH OF THE COUNTRY, A FLOODING POSSIBLE HAZARD REMAINS POSTED FOR MANY PARTS
OF THE SOUTHEASTERN CONUS. MANY LOCATIONS WITHIN THE HIGHLIGHTED AREA HAVE
REGISTERED WELL ABOVE-NORMAL PRECIPITATION SINCE EARLY FEBRUARY, WITH
ADDITIONAL AMOUNTS UPWARDS OF 3 INCHES EXPECTED DURING WEEK-1 (BASED ON WPC
QPF) AS THE AREA IS EXPECTED TO REMAIN VULNERABLE FOR LONG DURATION FLOODING.
TROUGHING AND ASSOCIATED ENHANCED ONSHORE FLOW IS LIKELY TO PROMOTE
ABOVE-NORMAL PRECIPITATION AND ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF ALASKA
DURING WEEK-2. THIS IS REFLECTED IN BOTH THE GEFS AND ECMWF PETS, DEPICTING AT
LEAST A 20 PERCENT CHANCE FOR 3-DAY AMOUNTS EXCEEDING THE 85TH PERCENTILE,
ALTHOUGH ACTUAL AMOUNTS ARE UNSUPPORTIVE TO POST ANY CORRESPONDING HAZARD.
HOWEVER, IT SHOULD BE NOTED THAT WARMER TEMPERATURES FAVORED DURING WEEK-2
COULD RESULT IN HIGHER FREEZING LEVELS (~4000 FT), WHICH COMBINED WITH ANY
ENHANCED PRECIPITATION COULD LEAD TO AN INCREASED RISK OF RUNOFF WITH POSSIBLE
LANDSLIDES. THERE ARE ALSO INCREASED SIGNALS IN THE PETS FOR ENHANCED
PRECIPITATION EXTENDING INTO THE PACIFIC NORTHWEST, ALTHOUGH DAILY TOTALS ARE
ALSO MARGINAL IN TERMS OF SUPPORTING A PRECIPITATION HAZARD.
FORECASTER: THOMAS COLLOW
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