559
FXUS21 KWNC 152105
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 15 2024
SYNOPSIS: MID-LEVEL LOW PRESSURE IS FORECAST INITIALLY OVER THE BERING SEA AND
GULF OF ALASKA IS PREDICTED TO SHIFT SOUTHWARD AND EASTWARD THROUGHOUT WEEK-2,
WHILE A SECONDARY AREA OF MID-LEVEL LOW PRESSURE IS FORECAST TO FORM OVER THE
CALIFORNIA COAST AT THE ONSET OF THE PERIOD. THIS PATTERN IS ANTICIPATED TO
BRING PERIODS OF HEAVY PRECIPITATION (RAIN AND HIGH ELEVATION SNOW) AND HIGH
WINDS TO PARTS OF THE WEST COAST BY THE MIDDLE OF THE PERIOD, HEAVY SNOW TO
HIGH ELEVATIONS OF THE NORTHERN AND CENTRAL ROCKIES, AND EASTERN PORTIONS OF
THE GREAT BASIN, AND HIGH WINDS TO MANY AREAS EAST OF THE ROCKIES. A PREDICTED
STORM IN THE NORTHEAST AT THE BEGINNING OF THE PERIOD COMBINED WITH A SURFACE
LOW SHIFTING NORTHEASTWARD FROM THE MISSISSIPPI VALLEY LEADS TO INCREASED
CHANCES FOR HEAVY SNOW OVER THE NORTHEASTERN CONTIGUOUS U.S. (CONUS) INCLUDING
LAKE EFFECT SNOW AT THE BEGINNING OF WEEK-2 FOLLOWED BY PERIODS OF HEAVY
PRECIPITATION ACROSS THE SOUTHEASTERN CONUS. SURFACE LOW PRESSURE SYSTEMS OVER
THE BERING SEA AND GULF OF ALASKA INCREASES THE RISK FOR HIGH WINDS FOR MANY
PARTS OF THE SOUTHERN COAST OF ALASKA AT THE BEGINNING OF WEEK-2.
HAZARDS
SLIGHT RISK OF PERIODS OF HEAVY PRECIPITATION ACROSS THE PACIFIC NORTHWEST AND
CALIFORNIA, SUN-THU, FEBRUARY 25-29.
SLIGHT RISK OF PERIODS OF HEAVY SNOW FOR THE SIERRA NEVADA, KLAMATH, AND
CASCADE MOUNTAINS, SUN-THU, FEBRUARY 25-29.
SLIGHT RISK OF EPISODIC HIGH WINDS FOR MUCH OF THE WEST COAST, SUN-THU,
FEBRUARY 25-29.
SLIGHT RISK OF EPISODIC HIGH WINDS FOR PORTIONS OF THE HIGH PLAINS, FRI-THU,
FEB 23-29.
SLIGHT RISK OF HEAVY SNOW FOR THE NORTHERN AND CENTRAL ROCKIES, AND EASTERN
PORTIONS OF THE GREAT BASIN, MON-THU, FEB 26-29.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE EASTERN CONUS, FRI-SUN, FEB 23-25.
SLIGHT RISK OF PERIODS OF HEAVY SNOW FOR PARTS OF THE GREAT LAKES AND
NORTHEASTERN CONUS, FRI-SUN, FEB 23-25.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PORTIONS OF THE LOWER MISSISSIPPI,
OHIO, AND TENNESSEE VALLEYS, AND SOUTHEAST, MON-WED, FEB 26-28.
SLIGHT RISK FOR PERIODS OF HIGH WINDS FOR THE SOUTHERN COAST OF ALASKA FROM THE
ALASKA PENINSULA TO SOUTHEASTERN ALASKA, THU-FRI, FEB 23-24.
POSSIBLE FLOODING FOR SOUTHWESTERN OREGON AND MUCH OF CALIFORNIA.
DETAILED SUMMARY
FOR SUNDAY FEBRUARY 18 - THURSDAY FEBRUARY 22:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY FEBRUARY 23 - THURSDAY FEBRUARY 29: MID-LEVEL TROUGHING PREDICTED
OVER THE BERING SEA AND GULF OF ALASKA AT THE ONSET OF WEEK-2 IS SLIGHTLY MORE
AMPLIFIED COMPARED TO YESTERDAY, TRANSLATING TO STRONGER SIGNALS IN ENHANCED
PRECIPITATION FOR THE WEST. PROBABILITIES OF ENHANCED INTEGRATED VAPOR
TRANSPORT (IVT) FOR THE WEST COAST REMAIN SIGNIFICANTLY LOWER THAN WEEK-1,
ALTHOUGH HAVE INCREASED COMPARED TO YESTERDAY. THE SLIGHT RISK OF PERIODS OF
HEAVY PRECIPITATION REMAINS POSTED FOR NORTHERN AND CENTRAL CALIFORNIA AND THE
PACIFIC NORTHWEST IS MAINTAINED FOR FEB 25-29 SIMILAR TO YESTERDAY. THE
PROBABILITIES IN THE GEFS, ECENS, AND CANADIAN PROBABILISTIC EXTREMES TOOLS
(PETS) CONTINUE TO NOT REACH MODERATE RISK (>40% CHANCE), BUT IT SHOULD BE
NOTED THAT THE DAILY ENSEMBLE MEANS INDICATE GREATER DAILY LIQUID EQUIVALENT
TOTALS COMPARED TO YESTERDAY IN ADDITION TO INDICATIONS OF HEAVY PRECIPITATION
LASTING FOR A LONGER DURATION OVER THE PACIFIC NORTHWEST. A SLIGHT RISK FOR
HEAVY SNOW AT HIGH ELEVATIONS IS CONTINUED FOR THE SIERRA NEVADA, KLAMATH, AND
CASCADE MOUNTAINS FOR THE SAME PERIOD. THIS IS ALSO SUPPORTED BY GEFS PET
INDICATES AT LEAST A 20% CHANCE OF 3-DAY SNOW WATER EQUIVALENT (SWE) TOTALS
EXCEEDING THE 85TH PERCENTILE AND ONE INCH. A SLIGHT RISK OF HIGH WINDS IS
DESIGNATED FOR MUCH OF THE WEST COAST EXCLUDING SOUTHERN CALIFORNIA FOR THE
SAME PERIOD AS WELL AS THE CONTINUED RISK FOR POSSIBLE FLOODING FOR CALIFORNIA
AND SOUTHWESTERN OREGON DURING THE FORECAST PERIOD.
AS THE MID-LEVEL TROUGH SHIFTS INLAND TOWARDS THE END OF WEEK-2, ENHANCED
MOISTURE IS PREDICTED FOR PORTIONS OF THE INTERIOR WEST. A SLIGHT RISK OF
PERIODS OF HEAVY SNOW CONTINUES TO BE HIGHLIGHTED FOR THE NORTHERN AND CENTRAL
ROCKIES, AND EASTERN PORTIONS OF THE GREAT BASIN, FEB 26-29. THE GREATEST
CHANCES FOR HEAVIER AMOUNTS ARE INDICATED OVER THE NORTHERN ROCKIES AND
ADJACENT HIGH ELEVATION AREAS IN IDAHO.
THE MID-LEVEL TROUGH IS PREDICTED TO REMAIN OVER THE INTERIOR WEST FROM THE
MIDDLE TO END OF WEEK-2, INCREASING CHANCES FOR PERIODS OF POTENTIAL HAZARDS
FOR A LONG DURATION. GIVEN THIS ANTICIPATED PATTERN, A SLIGHT RISK OF EPISODIC
HIGH WINDS IS DESIGNATED FOR MUCH OF THE HIGH PLAINS THROUGHOUT WEEK-2, WHERE
PETS SHOW AT LEAST A 20% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH PERCENTILE
AND 20 MPH. ADDITIONALLY, A SLIGHT RISK FOR PERIODS OF HEAVY PRECIPITATION IS
HIGHLIGHTED ACROSS PORTIONS OF THE LOWER MISSISSIPPI, OHIO, AND TENNESSEE
VALLEYS, AND SOUTHEAST, FEB 26-28, DUE TO GOOD MODEL CONSISTENCY FROM YESTERDAY
AND INDICATIONS FROM MODELS AND THEIR ASSOCIATED TOOLS SHOWING BETTER AGREEMENT
WITH INCREASING WET SIGNALS IN THE AREA. THERE IS GOOD AGREEMENT AMONG THE GEFS
AND ECENS PETS SHOWING AT LEAST A 20% CHANCE OF 3-DAY RAINFALL EXCEEDING THE
85TH PERCENTILE AND ONE INCH IN THE HIGHLIGHTED RISK AREA.
A STORM IS PREDICTED TO DEVELOP OVER THE NORTHEAST BY THE START OF WEEK-2.
HEAVY SNOW IS POSSIBLE ACROSS PARTS OF THE NORTHEASTERN CONUS ASSOCIATED WITH
THE BACKSIDE OF THE SURFACE LOW INCLUDING HEAVY LAKE EFFECT SNOW, ESPECIALLY
SINCE THERE IS LITTLE ICE COVERAGE ACROSS THE GREAT LAKES. A SLIGHT RISK OF
HEAVY SNOW IS POSTED ACROSS PARTS OF THE GREAT LAKES AND NORTHEASTERN CONUS,
FEB 23-25. UNCALIBRATED ECENS ENSEMBLE MEANS INDICATE DAY 8 (FEB 23) BEING THE
MOST LIKELY DAY FOR WIDESPREAD HEAVY SNOW, WITH UP TO ONE TWO INCHES OR GREATER
OF SNOWFALL IN A 24-HOUR PERIOD IN NEW ENGLAND. A BROAD AREA OF SLIGHT RISK OF
HIGH WINDS IS HIGHLIGHTED FOR PARTS OF THE MISSISSIPPI VALLEY EASTWARD, FEB
23-25 ASSOCIATED WITH THIS INITIAL STORM IN THE NORTHEAST FOLLOWED BY THE
AFOREMENTIONED SURFACE LOW TRACKING EASTWARD FROM THE MISSISSIPPI VALLEY.
A SERIES OF STRONG LOW PRESSURE SYSTEMS ARE DEPICTED TRACKING FROM THE BERING
SEA INTO THE GULF OF ALASKA, BRINGING PERIODS OF STORMY WEATHER INTO THE
SOUTHERN COASTAL PORTIONS OF THE STATE. A SLIGHT RISK OF HIGH WINDS IS
HIGHLIGHTED FOR SOUTHERN COASTAL ALASKA EXTENDING FROM THE ALASKA PENINSULA TO
THE SOUTHEAST, FEB 23 TO 24, WHERE PETS SHOW AT LEAST A 20% CHANCE OF WIND
SPEEDS EXCEEDING THE 85TH PERCENTILE AND 40 MPH.
FORECASTER: MELISSA OU
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