698
FXUS21 KWNC 261914
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST JANUARY 26 2024
SYNOPSIS: AMPLIFIED MID-LEVEL LOW PRESSURE CENTERED OVER THE WEST COAST FAVORS
A STORMY PERIOD FOR PORTIONS OF THE WEST FROM THE END OF WEEK-1 CONTINUING INTO
SOME OF WEEK-2, WITH THE GREATEST ODDS FOR HIGH WINDS, HEAVY PRECIPITATION, AND
HIGH-ELEVATION SNOW ACROSS THE SOUTHWESTERN QUADRANT OF THE LOWER 48. PERIODS
OF HEAVY PRECIPITATION ARE POSSIBLE ACROSS THE SOUTHEASTERN CONTIGUOUS U.S. AS
THE MID-LEVEL LOW SHIFTS EASTWARD.
HAZARDS
HIGH RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE SOUTHERN GREAT BASIN, FOUR
CORNERS, AND SOUTHERN CALIFORNIA, SAT-MON, FEB 3-5.
MODERATE RISK OF HEAVY PRECIPITATION FOR MANY PARTS OF THE SOUTHWESTERN
QUADRANT OF THE CONUS, SAT-WED, FEB 3-7.
SLIGHT RISK OF PERIODS OF HEAVY PRECIPITATION FOR MUCH OF THE SOUTHWESTERN
QUADRANT OF THE CONUS, SAT-FRI, FEB 3-9.
HIGH RISK OF HEAVY SNOW FOR PARTS OF THE CENTRAL GREAT BASIN AND NORTH-CENTRAL
ARIZONA, SAT-MON, FEB 3-5.
MODERATE RISK OF HEAVY SNOW FOR PARTS OF THE CENTRAL GREAT BASIN, SIERRA
NEVADA, NORTHERN ARIZONA, AND CENTRAL AND SOUTHERN ROCKIES, SAT-TUE, FEB 3-6.
SLIGHT RISK OF PERIODS OF HEAVY SNOW ACROSS THE INTERIOR WEST, KLAMATH
MOUNTAINS, AND SIERRA NEVADA, SAT-FRI, FEB 3-9.
MODERATE RISK OF HIGH WINDS ALONG THE SOUTHERN COAST OF CALIFORNIA AND PORTIONS
OF ARIZONA AND NEW MEXICO, SAT-MON, FEB 3-5.
SLIGHT RISK OF HIGH WINDS FOR MUCH OF THE SOUTHWESTERN QUADRANT OF THE CONUS,
INCLUDING THE CENTRAL GREAT BASIN AND CENTRAL AND SOUTHERN PLAINS, SAT-WED, FEB
3-7.
MODERATE RISK OF PERIODS OF HEAVY PRECIPITATION FOR THE LOWER MISSISSIPPI AND
TENNESSEE VALLEYS AND ADJACENT SOUTHEAST, SAT-SUN, FEB 3-4.
SLIGHT RISK OF PERIODS OF HEAVY PRECIPITATION FOR MANY PARTS OF THE
SOUTHEASTERN QUADRANT OF THE CONUS, SAT-WED, FEB 3-7.
SLIGHT RISK OF HEAVY SNOW FOR PORTIONS OF THE NORTHERN ROCKIES AND NORTHERN
PLAINS, SAT-MON, FEB 3-5.
POSSIBLE FLOODING FOR MUCH OF ARIZONA AND ADJACENT NEW MEXICO.
POSSIBLE FLOODING FOR COASTAL PARTS OF CENTRAL AND SOUTHERN CALIFORNIA.
POSSIBLE FLOODING FOR THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS AND ALABAMA.
DETAILED SUMMARY
FOR MONDAY JANUARY 29 - FRIDAY FEBRUARY 02:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY FEBRUARY 03 - FRIDAY FEBRUARY 09: THERE CONTINUES TO BE GOOD
AGREEMENT IN MULTIPLE MODEL ENSEMBLE MEANS INDICATING AMPLIFIED MID-LEVEL
TROUGHING SHIFTING FROM NEAR THE WEST COAST LATE IN WEEK-1 TO BEING CENTERED
OVER THE COAST BY THE BEGINNING OF WEEK-2, GRADUALLY WEAKENING AS IT SHIFTS
EASTWARD. THE GREATEST IMPACTS FROM THE ASSOCIATED STORMY PATTERN ARE
ANTICIPATED FOR THE SOUTHWESTERN QUADRANT OF THE CONUS DAYS 8 TO 12 (FEB 3-7).
IN GENERAL, RELATED HAZARDS ACROSS THE WEST ARE VERY SIMILAR TO YESTERDAY.
THE ECENS PROBABILISTIC EXTREMES TOOL (PET) SHOWS HIGHER CHANCES FOR HEAVY
PRECIPITATION COMPARED TO THE GEFS AND CANADIAN COUNTERPARTS, WITH THE CANADIAN
HAVING THE WEAKEST SIGNAL. A HIGH RISK OF HEAVY PRECIPITATION IS DESIGNATED FOR
PORTIONS OF THE SOUTHWEST AND SOUTHERN CALIFORNIA, FEB 3-5, PRIMARILY BASED ON
WHERE THE ECENS PET INDICATES AT LEAST A 60% CHANCE OF 3-DAY LIQUID EQUIVALENT
EXCEEDING THE 85TH PERCENTILE CLIMATOLOGICALLY (GREATER THAN ONE INCH ACROSS
CALIFORNIA AND ARIZONA, HALF AN INCH ELSEWHERE). A MODERATE RISK FOR HEAVY
PRECIPITATION IS POSTED FOR MANY PARTS OF THE SOUTHWESTERN QUADRANT OF THE
CONUS, FEB 3-7, WHERE THE GEFS, ECENS, AND CANADIAN PETS INDICATE AT LEAST A
40% CHANCE OF EXCEEDING HAZARDS THRESHOLDS. A BROADER SLIGHT RISK (>20% CHANCE)
AREA IS HIGHLIGHTED ACROSS MUCH OF THE SOUTHWESTERN CONUS FOR THE ENTIRETY OF
WEEK-2. PET TOOLS CONTINUE TO INDICATE AT LEAST SLIGHT CHANCES FOR HEAVY
PRECIPITATION THROUGH THE END OF THE PERIOD PARTICULARLY FOR PARTS OF
CALIFORNIA.
FOR HEAVY SNOW, A HIGH RISK (>60% CHANCE) IS POSTED FOR PARTS OF THE CENTRAL
GREAT BASIN AND NORTH-CENTRAL ARIZONA, FEB 3-5, WITH AN ENCOMPASSING MODERATE
RISK (>40% CHANCE) ACROSS PARTS OF THE CENTRAL GREAT BASIN, SIERRA NEVADA,
NORTHERN ARIZONA, AND CENTRAL AND SOUTHERN ROCKIES, FEB 3-6. A BROAD AREA OF
SLIGHT RISK IS POSTED FOR THE ENTIRE WEEK-2 PERIOD (FEB 3-9) FOR THE HIGHER
ELEVATIONS OF THE SOUTHWESTERN CONUS, INCLUDING THE CENTRAL AND SOUTHERN
ROCKIES, KLAMATH MOUNTAINS, AND SIERRA NEVADA. LOW-PRESSURE MAY DEVELOP IN THE
LEE OF THE CENTRAL ROCKIES EARLY IN WEEK-2 AND BRING INCREASED CHANCES FOR
UPSLOPE SNOW TO PARTS OF THE NORTHERN PLAINS AND ROCKIES. THEREFORE, A SEPARATE
SLIGHT RISK OF HEAVY SNOW IS POSTED FOR THESE REGIONS FOR FEB 3-5. THE PETS
DEPICT THESE HEAVY SNOW RISK AREAS RECEIVING 3-DAY SNOW WATER EQUIVALENT TOTALS
EXCEEDING THE 85TH PERCENTILE AND HALF AN INCH, AND ONE INCH LOCALLY. FLOODING
IS ALSO POSSIBLE ACROSS PARTS OF COASTAL CALIFORNIA, ARIZONA, AND ADJACENT NEW
MEXICO DUE TO ANTECEDENT HEAVY PRECIPITATION DURING WEEK-1, WHICH IS EXPECTED
TO CONTINUE DURING WEEK-2.
POSSIBLE SURFACE LOW FORMATION ACROSS THE SOUTHWEST IN TANDEM WITH SURFACE HIGH
PRESSURE BUILDING ACROSS THE NORTHWEST MAY LEAD TO TIGHT PRESSURE GRADIENTS
ACROSS THE SOUTHWESTERN CONUS. MODERATE RISKS FOR HIGH WINDS ARE DESIGNATED FOR
THE SOUTHERN COAST OF CALIFORNIA AND PORTIONS OF ARIZONA AND NEW MEXICO, FEB
3-5, WHERE THE ECENS PET SHOWS AT LEAST A 40% CHANCE OF WIND SPEEDS EXCEEDING
THE 85TH PERCENTILE. A BROADER AREA IS HIGHLIGHTED WITH A SLIGHT RISK OF HIGH
WINDS ACROSS MUCH OF THE SOUTHWESTERN QUADRANT OF THE CONUS, INCLUDING THE
PORTIONS OF THE GREAT BASIN AND CENTRAL AND SOUTHERN PLAINS FOR THE SAME
PERIOD, WHERE ENHANCED WINDS ARE POSSIBLE AS SURFACE LOWS OVER THE SOUTHWEST
SHIFT EASTWARD.
AS THE MID-LEVEL TROUGH SHIFTS EASTWARD, ASSOCIATED SURFACE LOWS AND FRONTS ARE
PREDICTED TO MOVE FROM THE SOUTHWESTERN CONUS EASTWARD, BRINGING INCREASED
CHANCES FOR HEAVY PRECIPITATION TO PARTS OF THE LOWER MISSISSIPPI VALLEY AND
ADJACENT AREAS. HOWEVER, THERE IS SIGNIFICANTLY MORE UNCERTAINTY IN THE MODELS
REGARDING THE EVOLUTION OF THESE FEATURES TRANSLATING INTO LOWER CONFIDENCE IN
RESULTANT HAZARDS. DESPITE THE LACK OF ELEVATED CHANCES IN THE PETS, A MODERATE
RISK OF PERIODS OF HEAVY PRECIPITATION IS SPECIFIED FOR THE LOWER MISSISSIPPI
AND TENNESSEE VALLEYS AND ADJACENT SOUTHEAST, FEB 3-4, BASED ON RAW
PRECIPITATION OUTPUT FROM THE ENSEMBLE MEANS AND ANTECEDENT CONDITIONS
FEATURING SATURATED SOILS AND ELEVATED RIVER LEVELS WHICH SUPPORT A MODERATE
RISK. A BROADER SLIGHT RISK AREA IS HIGHLIGHTED ACROSS MANY PARTS OF THE
SOUTHEASTERN QUADRANT OF THE CONUS BASED ON WHERE PETS SHOW AT LEAST A 20%
CHANCE OF 3-DAY PRECIPITATION TOTALS EXCEEDING THE 85TH PERCENTILE AND ONE INCH
FOR FEB 3-7. A POSSIBLE FLOOD RISK IS DESIGNATED PRIMARILY WHERE THERE IS A
MODERATE RISK OF HEAVY PRECIPITATION AND THE NATIONAL WATER CENTER SHOWS
POSSIBLE FLOODING LEADING UP TO WEEK-2.
IN ALASKA, THERE ARE LINGERING CHANCES FOR MUCH BELOW-NORMAL TEMPERATURES EARLY
IN THE PERIOD, HOWEVER, THE SIGNAL DOES NOT APPEAR TO BE AS STRONG AS PRIOR
FORECASTS WITH THE BULK OF THE COLDEST TEMPERATURES FORECAST DURING WEEK-1.
THEREFORE, NO CORRESPONDING TEMPERATURE HAZARDS ARE POSTED TODAY. ANOTHER
CONCERN IS THE POTENTIAL FOR GAP WINDS ALONG THE SOUTHERN COASTAL RANGES OF
ALASKA. ENSEMBLE FORECASTS FROM THE GEFS AND ECENS INDICATE THE POTENTIAL FOR
AN AREA OF HIGH PRESSURE TO DEVELOP OVER THE YUKON TERRITORY DURING WEEK-2.
THIS COULD BRING HIGH WINDS TO PORTIONS OF SOUTHEAST ALASKA. HOWEVER, THE HIGH
PRESSURE DOES NOT LOOK PARTICULARLY STRONG AT THIS TIME AND LACK OF SURFACE LOW
PRESSURE IN THE GULF OF ALASKA MAY LIMIT THE STRENGTH OF THE GAP WINDS.
THEREFORE, NO CORRESPONDING WIND HAZARD IS POSTED AT THIS TIME.
FORECASTER: RYAN BOLT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page