020
FXUS21 KWNC 231934
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 23 2024
SYNOPSIS: THERE IS RELATIVELY GOOD MODEL AGREEMENT INDICATING MID-LEVEL LOW
PRESSURE INITIALLY OVER THE WESTERN THIRD OF THE CONTIGUOUS U.S. (CONUS)
SHIFTING EASTWARD DURING WEEK-2. THIS PATTERN FAVORS INCREASED CHANCES FOR
HEAVY PRECIPITATION (HIGH ELEVATION SNOW) ACROSS PARTS OF THE WESTERN CONUS AND
SOUTHEASTERN CONUS AND HIGH WINDS ACROSS COASTAL PORTIONS OF THE OREGON,
NORTHWESTERN CALIFORNIA, AND THE CENTRAL CONUS AT THE BEGINNING OF THE PERIOD.
IN ALASKA, ARCTIC HIGH PRESSURE OVER THE NORTHERN PARTS OF THE STATE MAY HELP
TO PROMOTE MUCH BELOW NORMAL TEMPERATURES AND GAP WINDS ACROSS THE SOUTHERN
MAINLAND.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE NORTHERN HALF OF CALIFORNIA
AND SOUTHERN OREGON, SAT, MAR 2.
SLIGHT RISK OF HEAVY SNOW FOR THE KLAMATH AND PORTIONS OF THE SIERRA NEVADA,
SAT, MAR 2.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST, SAT-MON,
MAR 2-4.
SLIGHT RISK OF HEAVY SNOW FOR THE CASCADES AND OLYMPIC MOUNTAINS, SAT-MON, MAR
2-4.
SLIGHT RISK OF HIGH WINDS FOR COASTAL PORTIONS OF OREGON AND NORTHWESTERN
CALIFORNIA, SAT-MON, MAR 2-4.
SLIGHT RISK OF PERIODS OF HEAVY SNOW FOR PARTS OF THE NORTHERN AND CENTRAL
ROCKIES AND ADJACENT GREAT BASIN, SAT-SUN, MAR 2-3.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE GREAT PLAINS AND UPPER AND MIDDLE
MISSISSIPPI VALLEY, SAT-MON, MAR 2-4.
SLIGHT RISK OF PERIODS OF HEAVY PRECIPITATION FOR PORTIONS OF THE SOUTHEASTERN
CONUS, SAT-MON, MAR 2-4.
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE SOUTHERN INTERIOR OF
ALASKA AND ALASKA PANHANDLE, SAT-SUN, MAR 2-3.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHERN ALASKA,
SAT-MON, MAR 2-4.
SLIGHT RISK FOR PERIODS OF HIGH WINDS FOR SOUTHERN COASTAL PORTIONS OF ALASKA
FROM NEAR YAKUTAT TO AROUND COLD BAY, SAT-TUE, MAR 2-5.
DETAILED SUMMARY
FOR MONDAY FEBRUARY 26 - FRIDAY MARCH 01:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY MARCH 02 - FRIDAY MARCH 08: THERE IS MUCH BETTER MODEL AGREEMENT
COMPARED TO RECENT DAYS REGARDING THE UPPER LEVEL PATTERN. AMPLIFIED MID-LEVEL
TROUGHING IS PREDICTED FOR THE WESTERN THIRD OF THE CONUS, SHIFTING EASTWARD
THROUGHOUT WEEK-2. MEANWHILE UPSTREAM, MID-LEVEL TROUGHING OVER THE GULF OF
ALASKA MAY EXTEND SOUTHWARD TO NEAR THE NORTHWESTERN CONUS COAST BY THE LATTER
HALF OF THE PERIOD ALBEIT MUCH LESS AMPLIFIED THAN THE PATTERN AT THE BEGINNING
OF THE PERIOD. THE ECENS FAVORS A MORE AMPLIFIED TROUGH AT THE BEGINNING OF THE
PERIOD COMPARED TO THE GEFS, TRANSLATING TO HIGHER CHANCES FOR ENHANCED
INTEGRATED VAPOR TRANSPORT (IVT), WITH BOTH MODELS SHOWING GREATEST
PROBABILITIES OF IVT EXCEEDING 250 KG/MS AT THE BEGINNING OF THE PERIOD,
INITIALLY ACROSS CALIFORNIA AND SHIFTING NORTHWARD BY DAY 9 (FEB 3). THUS
SLIGHT RISKS OF HEAVY PRECIPITATION ARE POSTED FOR THE NORTHERN HALF OF
CALIFORNIA AND SOUTHERN OREGON FEB 2, AND FOR THE PACIFIC NORTHWEST FEB 2-4
WITH CORRESPONDING SLIGHT RISKS OF HEAVY SNOW IN HIGH ELEVATION AREAS. THE
PROBABILISTIC EXTREMES TOOLS (PETS) INDICATE AT LEAST A 20% CHANCE OF 3-DAY
LIQUID EQUIVALENT PRECIPITATION TOTALS EXCEEDING THE 85TH PERCENTILE
CLIMATOLOGICALLY AND ONE INCH AT THE BEGINNING OF WEEK-2. THE ECENS
UNCALIBRATED DAILY ENSEMBLE MEANS SHOW GREATER PRECIPITATION TOTALS THAN THE
GEFS ASSOCIATED WITH THE MORE AMPLIFIED PATTERN. A SLIGHT RISK OF HIGH WINDS IS
POSTED FOR COASTAL PORTIONS OF OREGON AND NORTHWESTERN CALIFORNIA, MAR 2-4,
WHERE THE PETS INDICATE AT LEAST A 20% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH
PERCENTILE AND 40 MPH. THE POSSIBLE FLOOD RISK HAS BEEN REMOVED FROM NORTHERN
CALIFORNIA DUE TO DECREASING HEAVY PRECIPITATION SIGNALS DURING THE PERIOD.
A SLIGHT RISK OF HEAVY SNOW HAS BEEN SLIGHTLY EXPANDED IN TODAY'S OUTLOOK FOR
MAR 2-3 ACROSS PARTS OF THE NORTHERN AND CENTRAL ROCKIES AND ADJACENT GREAT
BASIN GIVEN BETTER MODEL AGREEMENT OF THE EVOLUTION OF THE MID-LEVEL TROUGH AND
ASSOCIATED SURFACE LOWS FORMING ACROSS THE REGION BRINGING HEAVY UPSLOPE SNOW
TO HIGHLIGHTED RISK AREAS. THESE SURFACE LOWS TRACKING NORTHEASTWARD SUPPORT A
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE GREAT PLAINS AND UPPER AND MIDDLE
MISSISSIPPI VALLEY, MAR 2-4, WHERE PETS INDICATE AT LEAST A 20% CHANCE OF WIND
SPEEDS EXCEEDING THE 85TH PERCENTILE AND 20 MPH (GREATER THAN 25 MPH ACROSS THE
CENTRAL AND SOUTHERN PLAINS).
ENHANCED MOIST SOUTHERLY FLOW FROM THE GULF OF MEXICO AHEAD OF THE MID-LEVEL
TROUGH ACROSS THE WEST SUPPORTS A SLIGHT RISK OF HEAVY PRECIPITATION ACROSS THE
SOUTHEASTERN CONUS, MAR 2-4. THERE CONTINUES TO BE GOOD AGREEMENT AMONG PETS
SHOWING AT LEAST A 20% CHANCE OF 3-DAY PRECIPITATION TOTALS EXCEEDING THE 85TH
PERCENTILE AND ONE INCH FOR THE HIGHLIGHTED RISK AREA. THE ECENS EXTENDS THESE
THRESHOLDS TO PARTS OF THE MID-ATLANTIC AND NORTHEAST DURING THE 8 TO 10 DAY
PERIOD. DUE TO THESE SIGNALS LACKING IN THE GEFS AND CANADIAN COUNTERPARTS THE
HEAVY PRECIPITATION RISK IS NOT EXTENDED FURTHER NORTH.
IN ALASKA, AN AREA OF ARCTIC HIGH PRESSURE IS FORECAST ACROSS NORTHERN PORTIONS
OF THE MAINLAND AND THE YUKON, CONTINUING INCREASED CHANCES FOR ANOMALOUS COLD
ACROSS THE STATE. THIS SURFACE HIGH IS PREDICTED TO RECEDE NORTH BY THE MIDDLE
OF THE PERIOD, DECREASING CHANCES FOR MUCH BELOW NORMAL TEMPERATURES. THIS
PATTERN CHANGE ALSO SUPPORTS A DECREASE IN SPATIAL COVERAGE OF THE ASSOCIATED
HAZARD RISKS. THIS IS REFLECTED IN DECREASING PROBABILITIES IN THE PETS OF
TEMPERATURES FALLING TO THE LOWEST 5TH PERCENTILE. A SLIGHT RISK FOR MUCH BELOW
NORMAL TEMPERATURES IS DESIGNATED FOR SOUTHERN ALASKA MAR 2-4, WITH AN EMBEDDED
AREA OF MODERATE RISK (>40% CHANCE) FOR THE SOUTHERN INTERIOR OF ALASKA AND
ALASKA PANHANDLE, MAR 2-3. SURFACE LOW PRESSURE OVER THE GULF OF ALASKA
COMBINED WITH SURFACE HIGH PRESSURE ACROSS THE MAINLAND CONTINUES TO SUPPORT
PERIODS OF HIGH GAP WINDS FOR THE SOUTHERN ALASKA COASTLINE FROM COLD BAY TO
YAKUTAT THROUGH THE MIDDLE OF THE WEEK-2 PERIOD. THUS, A SLIGHT RISK OF HIGH
WINDS IS MAINTAINED FOR MAR 2-5 ACROSS THE AREA. HIGH WINDS ACROSS THE SOUTHERN
COAST OF ALASKA COULD CONTRIBUTE TO ANOMALOUSLY LOW WIND CHILL VALUES IN THE
AREA.
FORECASTER: MELISSA OU
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