802
FXUS21 KWNC 131919
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 13 2025
SYNOPSIS: STRONG SURFACE HIGH PRESSURE DESCENDING FROM CANADA IS EXPECTED TO
BRING A SHOT OF ARCTIC AIR, ELEVATING THE RISK OF HAZARDOUSLY COLD TEMPERATURES
ACROSS MANY PARTS OF THE CENTRAL AND EASTERN CONTIGUOUS U.S, WITH EPISODES OF
HIGH WINDS OVER THE ROCKIES AND HIGH PLAINS EARLY IN WEEK-2. A DEPARTING
SURFACE LOW AND ACCOMPANYING FRONTAL SYSTEM INCREASES THE RISK OF HIGH WINDS
OVER MANY PARTS OF THE EASTERN U.S.
HAZARDS
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE CENTRAL AND
SOUTHERN PLAINS, LOWER AND MIDDLE MISSISSIPPI, TENNESSEE AND OHIO VALLEYS,
SOUTHEAST, APPALACHIANS, MID-ATLANTIC, AND LOWER GREAT LAKES, FRI, FEB 21.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR MUCH OF THE CENTRAL AND
EASTERN CONUS, EXCLUDING PARTS OF NEW ENGLAND, FRI-SAT, FEB 21-22.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE ROCKIES AND HIGH PLAINS, FRI-SAT,
FEB 21-22.
SLIGHT RISK OF HIGH WINDS FOR PARTS OF THE EASTERN GREAT LAKES, TENNESSEE AND
OHIO VALLEYS, APPALACHIANS, SOUTHEAST, MID-ATLANTIC, AND THE NORTHEAST,
FRI-SAT, FEB 21-22.
POSSIBLE FLOODING FOR THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS, SOUTHEAST,
AND THE APPALACHIANS.
DETAILED SUMMARY
FOR SUNDAY FEBRUARY 16 - THURSDAY FEBRUARY 20:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY FEBRUARY 21 - THURSDAY FEBRUARY 27: THE WEEK-2 HAZARDS PERSPECTIVE
REMAINS ON TRACK SINCE YESTERDAY. BOTH THE GEFS AND ECWMF ENSEMBLES CONTINUE TO
FAVOR MEAN 500-HPA TROUGHING LIFTING OUT OVER THE NORTHEASTERN CONUS, WITH A
POTENT MEAN SURFACE HIGH IN ITS WAKE, CONSISTENT WITH AN ARCTIC AIR OUTBREAK
OVERSPREADING MUCH OF THE CENTRAL AND EASTERN CONUS BY LATE NEXT WEEK. HEADING
INTO THE FOLLOWING WEEKEND (DAYS 9 AND 10), GUIDANCE CONTINUES TO SHOW SIGNS OF
BUILDING HEIGHTS OVER THE MISSISSIPPI VALLEY WITH ADDITIONAL SHORTWAVE ENERGY
UPSTREAM. WHILE THIS IS STILL EXPECTED TO EASE THE HAZARDOUS COLD RISK, ANY
WARMING MAY BE TEMPORARY, AS THERE IS GOOD AGREEMENT AMONG THE MODELS FAVORING
MORE OF A STABLE LONGWAVE RIDGE/TROUGH PATTERN UNFOLDING OVER THE CONUS FOR THE
REMAINDER OF WEEK-2.
WITH MUCH OF THE ANOMALOUSLY COLD AIR ESTABLISHED HEADING INTO WEEK-2, A BROAD
SLIGHT RISK AREA OF MUCH BELOW NORMAL TEMPERATURES REMAINS ISSUED FOR MUCH OF
THE CONUS EAST OF THE ROCKIES (EXCLUDING MUCH OF FLORIDA AND PARTS OF THE
NORTHEAST), AND VALID THROUGH DAY 9 (FEB 22). WITH THE CORE OF THE STRONGEST
NEGATIVE TEMPERATURE DEPARTURES ( >25 DEG F BELOW NORMAL BASED ON THE ECWMF
ENSEMBLE) FAVORED TO BE CENTERED OVER MIDDLE MISSISSIPPI VALLEY ON DAY 8 (FEB
21), A CORRESPONDING MODERATE RISK AREA ALSO REMAINS ISSUED WHERE PROBABILISTIC
EXTREMES TOOLS (PETS) CONTINUE TO INDICATE ELEVATED CHANCES (>40%) FOR MINIMUM
TEMPERATURES FALLING BELOW THE 10TH PERCENTILE. DUE TO BETTER AGREEMENT AMONG
THE TOOLS FOR MINIMUM TEMPERATURES REACHING HAZARDS CRITERIA FURTHER EAST, THE
MODERATE RISK AREA IS EXPANDED ACCORDINGLY TO INCLUDE PORTIONS OF THE
APPALACHIANS, MID-ATLANTIC, AND SOUTHEAST. ALTHOUGH PETS ARE SUPPORTIVE OF A
CONTINUATION OF THE HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR DAY 8 (FEB
21) FOR MUCH THE MIDWEST, THIS DESIGNATION IS REMOVED IN THE UPDATED OUTLOOK
BASED ON UNCALIBRATED TEMPERATURE GUIDANCE WHICH SHOWS THE ANOMALOUS COLD
PEAKING LATE IN WEEK-1, AND MAINTAINS A FAIRLY SWIFT WEAKENING OF THE
ANOMALOUSLY COLD TEMPERATURES OVER THE PLAINS AND MISSISSIPPI VALLEY TIED TO
BUILDING MID-LEVEL HEIGHTS. THIS IS ALSO REFLECTED IN THE PETS WHICH DEPICT A
SUBSTANTIAL REDUCTION IN COLD SIGNALS IN PERCENTILE SPACE FROM DAY 8 TO DAY 9.
NEVERTHELESS, THE EXPANDING AREA OF ARCTIC HIGH PRESSURE IS EXPECTED TO PRODUCE
GUSTY WINDS WHERE VERY LOW WIND CHILL TEMPERATURES ARE POSSIBLE IN THESE
HIGHLIGHTED RISK AREAS. WITH MORE LONGWAVE TROUGHING FAVORED TO DEVELOP OVER
THE MISSISSIPPI VALLEY LATER IN WEEK-2, PREVAILING NORTHWESTERLY FLOW IS
EXPECTED TO KEEP TEMPERATURES ON THE COLD SIDE, THOUGH THERE ISN'T MUCH SUPPORT
IN THE TOOLS TO INCLUDE ANY ADDITIONAL TEMPERATURE HAZARDS AT THIS TIME.
IN ADDITION TO THE POTENTIALLY HAZARDOUS COLD, THERE REMAINS GOOD SUPPORT IN
THE ENSEMBLES FOR AN INCREASED RISK OF HIGH WINDS CONSISTENT WITH BACKDOOR COLD
FRONT ACTIVITY ACROSS NEW MEXICO AND INTO NORTHERN MEXICO. THEREFORE, A SLIGHT
RISK OF HIGH WINDS REMAINS POSTED ACROSS THE ROCKIES AND HIGH PLAINS AND IS
EXTENDED THROUGH DAY 9 (FEB 22). ANY ELEVATED WINDS REALIZED MAY ENHANCE THE
WILDFIRE THREAT, PARTICULARLY IN THE SOUTHERN PLAINS WHERE DROUGHT CONDITIONS
ARE CURRENTLY BEING REGISTERED.
FATHER EAST, A FRONTAL SYSTEM STILL LOOKS TO BE ON TRACK LATE NEXT WEEK WHERE
ENHANCED PRECIPITATION OVER THE SOUTHEAST AND SNOWFALL OVER PORTIONS OF THE
EASTERN SEABOARD IS FAVORED. ALTHOUGH SOME DETERMINISTIC SOLUTIONS DEPICT A
SLOWER STORM TRACK, RESULTING IN ACCUMULATING SNOW OVER THE NORTHEAST BY THE
START OF WEEK-2, THERE IS GOOD AGREEMENT IN THE ENSEMBLES WHICH MAINTAIN A MEAN
LOW POSITION THAT IS WELL OFFSHORE WITH LITTLE TO NO SNOW SIGNALS IN ANY OF THE
TOOLS. THEREFORE, THE SLIGHT RISK OF HEAVY SNOW IS REMOVED IN THE UPDATED
OUTLOOK. HOWEVER, GIVEN THE STRENGTH OF THE ARCTIC SURFACE HIGH ADVANCING
EASTWARD WITH A TIGHT MEAN SURFACE GRADIENT BEHIND THE DEPARTING LOW, A SLIGHT
RISK OF HIGH WINDS REMAINS ISSUED OVER THE MID-ATLANTIC AND THE NORTHEAST.
BASED ON THE LATEST ENSEMBLES, THE SLIGHT RISK HAS BEEN EXTENDED AN EXTRA DAY,
NOW VALID THROUGH FEB 22.
LATER IN THE PERIOD, ADDITIONAL SURFACE LOW FORMATION IS POSSIBLE AS ANY
DEVELOPMENT WOULD APPEAR MOST LIKELY OVER THE SOUTHERN TIER OF THE U.S. TIED TO
THE AFOREMENTIONED SHORTWAVE ENERGY UPSTREAM. CONSISTENT WITH PREVIOUS
GUIDANCE THOUGH, ANY HEAVY PRECIPITATION RISK REMAINS PRETTY MUTED IN BOTH THE
RAW AND CALIBRATED TOOLS, AND NO PRECIPITATION OR SNOW HAZARDS ARE HIGHLIGHTED.
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
ESPECIALLY IF ANY ADDITIONAL PRECIPITATION OCCURS DURING WEEK-2.
UPSTREAM, ENSEMBLES CONTINUE TO FAVOR MID-LEVEL RIDGING ACROSS THE WESTERN
CONUS WITH CONDITIONS FAVORED TO BECOME MUCH DRIER, ESPECIALLY ACROSS
CALIFORNIA. WITH THE MEAN FLOW PATTERN LOOKING TO BECOME MORE OFFSHORE LATER IN
WEEK-2, PORTIONS OF THE WEST 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
WEST COAST RECENTLY, THIS PART OF THE COUNTRY LOOKS TO BE LESS SUSCEPTIBLE TO
ANY WILDFIRE RISK.
FOR ALASKA, ENHANCED ONSHORE FLOW IS LIKELY TO PROMOTE ABOVE-NORMAL
PRECIPITATION AND ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE STATE DURING
WEEK-2. THIS IS REFLECTED IN BOTH THE GEFS AND ECMWF PETS, DEPICTING INCREASED
CHANCES FOR 3-DAY AMOUNTS EXCEEDING THE 85TH PERCENTILE, THOUGH 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.
FORECASTER: NICK NOVELLA
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