997
FXUS21 KWNC 251937
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 25 2025
SYNOPSIS: EARLY IN MARCH THERE ARE INCREASED CHANCES FOR HEAVY PRECIPITATION
AND SNOW ACROSS THE EAST AND WEST COASTS OF THE CONTIGUOUS U.S. (CONUS). IN THE
EAST, AN AREA OF SURFACE LOW PRESSURE IS FORECAST TO BRING INCREASED CHANCES
FOR HEAVY RAIN AND STRONG WINDS TO THE EASTERN SEABOARD. MEANWHILE, ANOTHER
SYSTEM IS FORECAST TO BRING POSSIBLY HEAVY PRECIPITATION TO CALIFORNIA AND
SOUTHWESTERN OREGON, WITH HEAVY SNOW POSSIBLE ACROSS PORTIONS OF THE SIERRA
NEVADA AND CASCADE MOUNTAINS.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR MUCH OF THE EASTERN SEABOARD AND EASTERN
GULF COAST, WED, MAR 5.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE SOUTHEAST, MID-ATLANTIC, AND
TENNESSEE VALLEY, WED-THU, MAR 5-6.
MODERATE RISK OF HEAVY SNOW FOR PORTIONS OF THE SIERRA NEVADA, KLAMATH, AND
SOUTHERN CASCADE MOUNTAINS, FRI-SUN, MAR 7-9.
SLIGHT RISK OF HEAVY SNOW FOR MUCH OF THE SIERRA NEVADA, KLAMATH, AND SOUTHERN
CASCADE MOUNTAINS, WED-TUE, MAR 5-11.
SLIGHT RISK OF HEAVY SNOW FOR THE NORTHERN CASCADE MOUNTAINS FOR FRI-TUE, MAR
7-11.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF SOUTHWESTERN OREGON AND
CALIFORNIA, FRI-TUE, MAR 7-11.
DETAILED SUMMARY
FOR FRIDAY FEBRUARY 28 - TUESDAY MARCH 04:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY MARCH 05 - TUESDAY MARCH 11: THERE IS GOOD AGREEMENT AMONG THE
DYNAMICAL MODELS 500-HPA HEIGHT FORECASTS FOR THE WEEK-2 PERIOD ACROSS THE
COUNTRY IN TODAY’S GUIDANCE. A SHORTWAVE TROUGH CROSSING THE CONUS EARLY IN THE
WEEK-2 PERIOD, IS FAVORED TO DEVELOP INTO A DEEPER AND BROADER TROUGH ACROSS
THE EAST BY THE MIDDLE OF WEEK-2. A SECOND TROUGH IS FORECAST TO DEVELOP ACROSS
THE EASTERN PACIFIC AND BRING MID-LEVEL ZONAL TO SLIGHTLY SOUTHERLY FLOW INTO
THE WEST COAST.
EARLY IN THE PERIOD, THE DYNAMICAL TOOLS FROM THE ECENS AND GEFS SUPPORT A
BROAD AREA HIGHLIGHTED WITH A SLIGHT RISK OF HEAVY PRECIPITATION ACROSS MUCH OF
THE EASTERN SEABOARD AND NEARBY REGIONS. THE ECENS PROBABILISTIC EXTREMES TOOL
(PET) INDICATES A BROAD AREA OF 30-50% CHANCES OF 3-DAY ACCUMULATED
PRECIPITATION AMOUNTS EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE AND 1 INCH
ACROSS MUCH OF THE SOUTHERN ATLANTIC STATES. WHILE THE GEFS PET IS NOT AS
STRONGLY SUPPORTIVE THERE IS AGREEMENT BETWEEN THE TOOLS FOR ENHANCED
PRECIPITATION FOR THIS REGION. THEREFORE, A SLIGHT RISK OF HEAVY PRECIPITATION
IS FORECAST FOR MAR 5 ACROSS MUCH OF THE EASTERN SEABOARD AND EASTERN GULF
COAST. ASSOCIATED WITH THIS SYSTEM, HIGH WINDS ARE ALSO POSSIBLE. PETS FROM THE
GEFS AND ECENS ARE SUPPORTIVE OF A SLIGHT RISK, THUS AN ASSOCIATED HIGH WIND
HAZARD IS POSTED FOR MAR 5-6. FURTHER NORTH, THERE IS SOME SUPPORT FROM THE
GEFS FOR HEAVY SNOW ALONG THE NORTHERN PERIPHERY OF THE SYSTEM. HOWEVER,
TEMPERATURES ARE UNCERTAIN AND SUPPORT FROM THE ECENS IS LIMITED. THEREFORE, NO
ASSOCIATED SNOW HAZARD IS POSTED AT THIS TIME.
IN THE WEST, THE DYNAMICAL MODEL TOOLS ARE COMING INTO BETTER AGREEMENT ON THE
STRENGTH, TIMING, AND LOCATION OF HEAVY SNOW AND PRECIPITATION CHANCES DURING
WEEK-2. EARLY IN WEEK-2, A WEAK AREA OF LOW-PRESSURE IS FORECAST TO IMPACT
PORTIONS OF CALIFORNIA. THIS MAY BRING INCREASED CHANCES FOR HEAVY SNOW TO
PORTIONS OF THE SIERRA NEVADA, KLAMATH, AND SOUTHERN CASCADES. HOWEVER,
FOLLOWING THIS SYSTEM, A STRONGER PRECIPITATION EVENT MAY TAKE PLACE. THE PETS
FROM THE GEFS AND ECENS ARE INDICATING INCREASED CHANCES BY THE MIDDLE OF
WEEK-2 FOR HEAVY PRECIPITATION AND HIGHER ELEVATION SNOW. INTEGRATED VAPOR
TRANSPORT (IVT) TOOLS FROM THE GEFS AND ECENS INDICATE INCREASED PROBABILITIES
FOR ENHANCED WATER VAPOR TRANSPORT INTO THE WEST COAST. THERE REMAIN SOME
DIFFERENCES IN THE TIMING AND LOCATION OF THE STRONG VAPOR TRANSPORT BETWEEN
THE ECENS AND GEFS BUT TOOLS HAVE GROWN MORE SUPPORTIVE IN THE LAST 24 HOURS.
BY THE MIDDLE OF THE WEEK-2 PERIOD, THE PETS BROADLY PREDICT 30-50% CHANCES OF
PRECIPITATION EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE AND AREAS OF 2
INCHES OF 3-DAY ACCUMULATED LIQUID EQUIVALENT ACROSS HIGH ELEVATION AREAS OF
NORTHERN CALIFORNIA. THEREFORE, A SLIGHT RISK OF HEAVY SNOW IS POSTED FOR MAR
5-11, ACROSS THE SIERRA NEVADA, KLAMATH, AND SOUTHERN CASCADE MOUNTAINS.
EMBEDDED WITHIN THE SLIGHT RISK IS A MODERATE RISK OF HEAVY SNOW FOR MARCH 7-9.
AN EXTENSION OF THE SLIGHT RISK OF HEAVY SNOW IS ADDED FOR THE REMAINDER OF THE
CASCADE MOUNTAINS FOR MAR 7-11. FINALLY, A SLIGHT RISK OF HEAVY PRECIPITATION
IS ADDED FOR MUCH OF CALIFORNIA AND SOUTHWESTERN OREGON FOR MAR 7-11.
ANTICIPATED HEAVIER PRECIPITATION COULD INCREASE CHANCES OF LOCALIZED FLOODING,
PARTICULARLY ACROSS PORTIONS OF NORTHERN CALIFORNIA AND INCREASED CONCERNS
AROUND BURN SCARS AROUND THE REGION. HOWEVER, DUE TO UNCERTAINTY IN THE
PRECIPITATION TOTALS AN ASSOCIATED FLOOD HAZARD IS NOT DESIGNATED AT THIS TIME.
FORECASTER: RYAN BOLT
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