073
FXUS21 KWNC 151935
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 15 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 TO THE GULF COAST. ALONG THE
WEST COAST, RENEWED CHANCES FOR ONSHORE FLOW INTO THE PACIFIC NORTHWEST
INCREASE CHANCES 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, TUE-THU, JAN 23-25.
SLIGHT RISK FOR HEAVY PRECIPITATION ACROSS PORTIONS OF THE SOUTHERN PLAINS,
OHIO, TENNESSEE AND LOWER MISSISSIPPI VALLEYS, SOUTHEAST, AND SOUTHERN
APPALACHIAN MOUNTAINS, TUE-SAT, JAN 23-27.
SLIGHT RISK FOR HIGH ELEVATION SNOW ACROSS PORTIONS OF THE FOUR CORNERS REGION,
TUE-THU, JAN 23-25.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST AND
NORTHERN AND CENTRAL CALIFORNIA, TUE-THU, JAN 23-25.
SLIGHT RISK OF HEAVY SNOW ACROSS THE SIERRA NEVADA AND CASCADE MOUNTAINS,
TUE-THU, JAN 23-25.
SLIGHT RISK OF HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN ROCKIES, WED-FRI, JAN
24-26.
SLIGHT RISK OF HIGH WINDS ALONG THE WEST COAST, TUE-THU, JAN 23-25.
FLOODING POSSIBLE FOR PORTIONS OF THE NORTHERN SIERRA NEVADA AND CASCADE
MOUNTAIN FOOTHILLS.
DETAILED SUMMARY
FOR THURSDAY JANUARY 18 - MONDAY JANUARY 22:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY JANUARY 23 - MONDAY JANUARY 29: THE EASTERN CONUS LOOKS 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 GULF COAST 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 2 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. THEREFORE, A MODERATE RISK OF HEAVY PRECIPITATION IS
POSTED FOR PORTIONS OF EASTERN TEXAS AND THE LOWER-MISSISSIPPI VALLEY FOR JAN
23-25. 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 23-27
PERIOD.
ON THE BACKSIDE OF THE MID-LEVEL SHORTWAVE OVER THE SOUTHERN PLAINS, THERE IS A
SLIGHT RISK FOR HEAVY SNOW POSTED FOR THE HIGHER ELEVATIONS OF THE FOUR
CORNERS. 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 23-25.
AN AREA OF DEEPLY NEGATIVE ANOMALOUS 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 TO 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 AND NORTHERN SIERRA NEVADA MOUNTAINS. THEREFORE, A SLIGHT RISK OF
HEAVY PRECIPITATION IS POSTED FOR PARTS OF CENTRAL AND NORTHERN CALIFORNIA
THROUGH THE PACIFIC NORTHWEST FOR JAN 23-25. AN ASSOCIATED SLIGHT RISK OF HEAVY
SNOW IS POSTED FOR THE HIGHEST ELEVATIONS OF THE CASCADES AND SIERRA NEVADA FOR
JAN 23-25. 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. THEREFORE, A SLIGHT RISK OF HIGH WINDS IS POSTED FROM THE SAN
FRANCISCO BAY AREA, NORTH TO THE OLYMPIC PENINSULA FOR JAN 23-25.
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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