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FXUS21 KWNC 161922
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 16 2024
SYNOPSIS: A RAPID WARM-UP IS FORECAST FOR EARLY IN THE WEEK-2 PERIOD ACROSS THE
EASTERN CONTIGUOUS U.S. (CONUS) REDUCING CHANCES FOR MUCH BELOW NORMAL
TEMPERATURES. AS THE ARCTIC HIGH PRESSURE FORECAST IN WEEK-1 PROGRESSES
EASTWARD, SOUTHERLY FLOW FROM THE GULF OF MEXICO ALONG WITH MID-LEVEL LOW
PRESSURE BRING INCREASED CHANCES FOR HEAVY RAIN IN PARTS OF THE EASTERN CONUS.
ALONG THE WEST COAST, CHANCES FOR ONSHORE FLOW INTO THE PACIFIC NORTHWEST
INCREASE THE LIKELIHOOD FOR HEAVY RAIN, SNOW, AND HIGH WINDS FOR PARTS OF THE
WEST.
HAZARDS
MODERATE RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF EASTERN TEXAS AND THE
LOWER MISSISSIPPI VALLEY, WED-THU, JAN 24-25.
SLIGHT RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF THE SOUTHERN PLAINS,
OHIO, TENNESSEE AND LOWER MISSISSIPPI VALLEYS, SOUTHEAST, AND SOUTHERN
APPALACHIAN MOUNTAINS, WED-SAT, JAN 24-27.
SLIGHT RISK FOR HIGH ELEVATION SNOW ACROSS COLORADO AND NEW MEXICO, WED-FRI,
JAN 24-26.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST AND
NORTHERN AND CENTRAL CALIFORNIA, WED-FRI, JAN 24-26.
SLIGHT RISK OF HEAVY SNOW ACROSS THE CASCADE MOUNTAINS, WED-FRI, JAN 24-26.
SLIGHT RISK OF HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN ROCKIES, WED-FRI, JAN
24-26.
SLIGHT RISK OF HIGH WINDS ALONG THE PACIFIC NORTHWEST COAST, WED-FRI, JAN 24-26.
FLOODING POSSIBLE FOR PORTIONS OF THE FOOTHILLS OF THE CASCADE MOUNTAINS.
DETAILED SUMMARY
FOR FRIDAY JANUARY 19 - TUESDAY JANUARY 23:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY JANUARY 24 - TUESDAY JANUARY 30: THE EASTERN CONUS IS LIKELY TO
SEE A RAPID WARM-UP FROM THE MUCH BELOW-NORMAL TEMPERATURES FORECAST DURING THE
WEEK-1 PERIOD. SURFACE HIGH PRESSURE PROGRESSES EASTWARD TOWARDS THE EAST COAST
WHILE POSITIVE 500-HPA HEIGHT ANOMALIES BUILD ACROSS THE GREAT LAKES. THIS
LEADS TO SOUTHERLY FLOW OFF THE GULF OF MEXICO FOR MUCH OF THE EASTERN CONUS
EARLY IN THE WEEK-2 PERIOD. A WEAK MID-LEVEL SHORTWAVE TROUGH IS FORECAST OVER
THE SOUTHERN PLAINS AT THE ONSET OF THE PERIOD. THIS PATTERN LEADS TO INCREASED
CHANCES FOR HEAVY PRECIPITATION TO PARTS OF THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI VALLEY AND MORE BROADLY ACROSS MUCH OF THE SOUTHEASTERN CONUS. THE
ECMWF PROBABILISTIC EXTREMES TOOL (PET) FORECASTS A GREATER THAN 50% CHANCE FOR
AN AREA ACROSS THE CENTRAL GULF COAST AND LOWER MISSISSIPPI VALLEY TO HAVE
3-DAY PRECIPITATION TO EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND 1.5 INCHES
OF PRECIPITATION. THE GEFS PET IS GENERALLY WEAKER IN THESE AREAS BUT CONTINUES
TO SUPPORT A GREATER THAN 30% CHANCE OF EXCEEDING THE 85TH CLIMATOLOGICAL
PERCENTILE AND 1 INCH OF PRECIPITATION. RAW MODEL TOOLS ARE IN SUPPORT OF THE
HEAVY PRECIPITATION RISK INTO THIS REGION AND INDICATE MUCH OF THIS
PRECIPITATION WILL FALL ON THE FIRST THREE DAYS OF THE PERIOD. THERE MAY BE
SOME CONCERNS FOR RAIN TO FALL ON SNOW ACROSS NORTHERN PORTIONS OF THE LOWER
MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS DUE TO PREVIOUSLY VERY COLD CONDITIONS
PRIOR TO THE WEEK-2 PERIOD. THEREFORE, A MODERATE RISK OF HEAVY PRECIPITATION
IS POSTED FOR PORTIONS OF EASTERN TEXAS AND THE LOWER MISSISSIPPI VALLEY FOR
JAN 24-25. A BROADER SLIGHT RISK IS POSTED FOR MUCH OF THE SOUTHEASTERN CONUS
NORTH TO THE OHIO RIVER VALLEY WHERE TOOLS ARE A BIT WEAKER WITH LESS
PRECIPITATION AND LOWER CHANCES OF EXCEEDING THE 85TH PERCENTILE BUT PET
EXTREMES TOOLS INDICATE AT LEAST AN INCH OF PRECIPITATION OVER 3 DAYS DURING
THE JAN 24-27 PERIOD.
ON THE BACK SIDE OF THE MID-LEVEL SHORTWAVE OVER THE SOUTHERN PLAINS, THERE IS
A SLIGHT RISK FOR HEAVY SNOW POSTED FOR THE HIGHER ELEVATIONS OF THE SOUTHERN
ROCKIES. THE GEFS SNOW WATER EQUIVALENT (SWE) PET INDICATES SLIGHT CHANCES FOR
EXCEEDING THE 85TH PERCENTILE AND HALF AN INCH OF SWE. THE ECMWF PRECIPITATION
PET ALSO SUPPORTS PRECIPITATION EXCEEDING THE 85TH PERCENTILE AND 0.5 INCHES.
MEANWHILE, RAW TOOLS AND THE MID-LEVEL HEIGHT PATTERN GENERALLY SUPPORT
INCREASED CHANCES FOR PRECIPITATION INTO THESE REGIONS. THEREFORE, A SLIGHT
RISK OF HEAVY SNOW IS POSTED FOR THESE AREAS FOR JAN 24-26.
AN AREA OF STRONGLY ANOMALOUS NEGATIVE 500-HPA HEIGHTS ALONG WITH AN ASSOCIATED
AREA OF SURFACE LOW-PRESSURE IS FORECAST IN THE GULF OF ALASKA AT THE ONSET OF
WEEK-2. THIS IS LIKELY TO BRING PRECIPITATION TO PORTIONS OF SOUTHEAST AND
SOUTH-CENTRAL ALASKA DURING WEEK-2 BUT IS UNLIKELY TO BRING HAZARDOUS
CONDITIONS. NEVERTHELESS, WITH STRONGLY ABOVE-NORMAL TEMPERATURES BEING FAVORED
IN THE WEEK-2 FORECAST THERE MAY BE CONCERN FOR LIQUID PRECIPITATION TO FALL ON
SNOW CAUSING SOME HYDROLOGICAL CONCERNS IN SOUTHEAST ALASKA. HOWEVER, IN THE
PACIFIC NORTHWEST, THIS SYSTEM MAY BRING HAZARDOUS PRECIPITATION AND WIND. THE
PETS FROM THE GEFS AND ECMWF INDICATE AT LEAST A 20% CHANCE OF 3 DAY
PRECIPITATION EXCEEDING THE 85TH PERCENTILE AND 2 INCHES OF PRECIPITATION.
TEMPERATURES ARE LIKELY TO BE ABOVE-NORMAL ACROSS THE WEST LEADING TO POTENTIAL
FOR RAIN TO FALL ONTO SNOWPACK IN THE FOOTHILLS OF THE CASCADES. SIGNALS FOR
HEAVY PRECIPITATION ARE REDUCED ACROSS CALIFORNIA RELATIVE TO PRIOR FORECASTS.
THEREFORE, A SLIGHT RISK OF HEAVY PRECIPITATION IS POSTED ONLY FOR THE PACIFIC
NORTHWEST FOR JAN 24-26. AN ASSOCIATED SLIGHT RISK OF HEAVY SNOW IS POSTED FOR
THE HIGHEST ELEVATIONS OF THE CASCADES FOR JAN 24-26. MEANWHILE, A FLOODING
POSSIBLE SHAPE REMAINS POSTED FOR THE WESTERN FOOTHILLS. AS THESE SYSTEMS MOVE
ONSHORE, WINDS MAY BE A CONCERN ALONG THE IMMEDIATE COAST AND A SLIGHT RISK OF
HIGH WINDS IS POSTED FROM SOUTHERN OREGON TO THE OLYMPIC PENINSULA FOR JAN
24-26.
IN ALASKA, THERE REMAIN SOME CONCERNS ABOUT THE POSSIBILITY OF GAP WINDS ACROSS
MUCH OF SOUTHERN ALASKA. HOWEVER, ARCTIC HIGH PRESSURE IS NOT FORECAST TO BE AS
ROBUST BY THE START OF THE WEEK-2 PERIOD AS AT THE END OF THE WEEK-1 PERIOD,
THEREFORE NO ASSOCIATED WIND HAZARD IS POSTED TODAY. IF THE HIGH PRESSURE
SHIFTS FURTHER NORTH ACROSS THE ARCTIC OCEAN, ELEVATED WINDS COULD BECOME A
CONCERN ACROSS PARTS OF THE NORTH SLOPE AND WILL NEED TO BE MONITORED IN THE
COMING DAYS.
FORECASTER: RYAN BOLT
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