951
FXUS21 KWNC 241936
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 24 2025
SYNOPSIS: DURING THE FIRST WEEK OF MARCH CHANCES FOR HEAVY PRECIPITATION AND
SNOW ARE POSSIBLE ACROSS THE CONTIGUOUS U.S. (CONUS). IN THE SOUTHEAST, AN AREA
OF SURFACE LOW PRESSURE IS FORECAST TO BRING INCREASED CHANCES FOR HEAVY RAIN
AND STRONG WINDS. HEAVY SNOW IS POSSIBLE IN PARTS OF THE ROCKIES AND INTO THE
CENTRAL PLAINS. MEANWHILE, ANOTHER SYSTEM IS FORECAST TO BRING POSSIBLY HEAVY
SNOW INTO PARTS OF THE SIERRA NEVADA AND CASCADE MOUNTAINS.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR MUCH OF THE SOUTHEASTERN CONUS, TUE-THU,
MAR 4-6.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE SOUTHEAST, MID-ATLANTIC, OHIO AND
TENNESSEE VALLEYS, TUE-THU, MAR 4-6.
SLIGHT RISK OF HEAVY SNOW FOR PORTIONS OF THE ROCKIES AND CENTRAL PLAINS,
TUE-THU, MAR 4-6.
SLIGHT RISK OF HEAVY SNOW FOR PORTIONS OF THE NORTHERN SIERRA NEVADA, KLAMATH,
AND SOUTHERN CASCADE MOUNTAINS, TUE-SAT, MAR 4-8.
SLIGHT RISK OF HEAVY SNOW FOR THE NORTHERN CASCADE MOUNTAINS FOR THU-SAT, MAR
6-8.
DETAILED SUMMARY
FOR THURSDAY FEBRUARY 27 - MONDAY MARCH 03:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY MARCH 04 - MONDAY MARCH 10: THERE IS MODERATELY GOOD AGREEMENT
AMONG THE DYNAMICAL MODELS 500-HPA HEIGHT FORECASTS FOR THE WEEK-2 PERIOD
ACROSS THE COUNTRY TODAY. THE ECENS IS SLIGHTLY MORE AMPLIFIED BRINGING
STRONGER RIDGING AND TROUGHING TO THE EAST COAST AND SOUTH-CENTRAL CONUS,
RESPECTIVELY. ALONG THE WEST COAST, THE ECENS MAINTAINS MORE NEGATIVE HEIGHT
ANOMALIES AND STRONGER ZONAL FLOW INTO THE WEST COAST EARLY IN THE WEEK-2
PERIOD. BY THE MIDDLE OF THE PERIOD, THE GEFS DEVELOPS A DEEP TROUGH IN THE
EASTERN CONUS AND MORE ZONAL FLOW INTO THE WEST. HOWEVER, THE ECENS FORECASTS A
DEEPER TROUGH ACROSS THE EASTERN PACIFIC WITH MORE SOUTHERLY MID-LEVEL FLOW
INTO THE WEST AND STRONGER SURFACE LOW-PRESSURE MOVING INTO THE WEST.
EARLY IN THE PERIOD, THE DYNAMICAL TOOLS FROM THE ECENS AND GEFS SUPPORT A
BROAD SLIGHT RISK OF HEAVY PRECIPITATION ACROSS THE SOUTHEASTERN CONUS AND
NEARBY REGIONS. THE ECENS PROBABILISTIC EXTREMES TOOL (PET) INDICATES A BROAD
AREA OF A 30-50% CHANCE OF 3 DAY PRECIPITATION AMOUNTS EXCEEDING THE 85TH
CLIMATOLOGICAL PERCENTILE AND 1 INCH ACROSS MUCH OF THE SOUTHEASTERN CONUS.
WHILE THE GEFS PET IS NOT AS STRONGLY SUPPORTIVE THERE IS AGREEMENT BETWEEN THE
TOOLS FOR PRECIPITATION INTO THIS REGION. FURTHERMORE, THE AREA HAS RECEIVED
SIGNIFICANT AMOUNTS OF PRECIPITATION IN THE PRIOR 10 DAYS WITH FLOODING ONGOING
IN PLACES. WHILE MUCH OF THIS FLOODING WILL LIKELY SUBSIDE BY THE WEEK-2
PERIOD, SOME ADDITIONAL SENSITIVITY IS LIKELY. THEREFORE, A BROAD SLIGHT RISK
OF PRECIPITATION IS FORECAST FOR MAR 4-6. ASSOCIATED WITH THIS SYSTEM, HIGH
WINDS ARE ALSO POSSIBLE. PETS FROM THE GEFS AND ECENS ARE SUPPORTIVE OF A
SLIGHT RISK AND AN ASSOCIATED HAZARD IS POSTED FOR THE SAME PERIOD. 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 PARTS OF THE ROCKIES AND INTO THE CENTRAL PLAINS, DYNAMICAL TOOLS SUPPORT
THE INCLUSION OF A SLIGHT RISK OF HEAVY SNOW EARLY IN WEEK-2. THE PETS FROM THE
ECENS AND GEFS BOTH BRING 20-40% CHANCES OF HEAVY PRECIPITATION TO THE REGION
AND THE SNOW WATER EQUIVALENT (SWE) PET FROM THE GEFS IS HIGHLIGHTING INCREASED
CHANCES FOR HEAVY SNOW. THEREFORE, A SLIGHT RISK OF HEAVY SNOW IS POSTED FOR
MAR 4-6 FOR THESE REGIONS.
IN THE WEST, THE DYNAMICAL MODEL TOOLS ARE IN THE LEAST AGREEMENT AT THIS TIME
AND HAVE DIFFERENCES IN TIMING AND STRENGTH OF PRECIPITATION. THE ECENS BEGINS
BRINGING PRECIPITATION INTO THE CENTRAL WEST COAST EARLY IN THE WEEK-2 PERIOD.
THE ECENS PET IS HIGHLIGHTING UP TO 40% CHANCES FOR 3-DAY PRECIPITATION AMOUNTS
TO EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE AND LOCALIZED AREAS OF 2 INCHES.
BY THE MIDDLE OF THE WEEK-2 PERIOD, THE ECENS PET BROADLY PREDICTS 30-50%
CHANCES OF PRECIPITATION EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE AND 2
INCHES OF PRECIPITATION. THE GEFS IS WEAKER AND SLOWER, NOT INCREASING
PRECIPITATION CHANCES UNTIL THE MIDDLE OF THE WEEK-2 PERIOD ACROSS PARTS OF THE
CENTRAL WEST COAST. THEREFORE, AT THIS TIME, ONLY A SLIGHT RISK OF HEAVY SNOW
IS POSTED FOR MAR 4-8, ACROSS THE NORTHERN SIERRA NEVADA, KLAMATH, AND SOUTHERN
CASCADE MOUNTAINS. THE SHAPE IS EXPANDED NORTH TO INCLUDE ALL OF THE CASCADE
MOUNTAINS FOR MAR 6-8. IF THE SIGNALS CONTINUE TO TREND TOWARDS A HEAVIER
PRECIPITATION OUTCOME THERE WILL BE CONCERNS FOR LOCALIZED FLOODING AND A
PRECIPITATION OR FLOOD HAZARD MAY BE APPROPRIATE IN THE COMING DAYS.
FORECASTER: RYAN BOLT
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