742
FXUS21 KWNC 261927
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FEBRUARY 26 2025
SYNOPSIS: DURING WEEK-2 THERE ARE INCREASED CHANCES FOR HEAVY PRECIPITATION AND
SNOW ACROSS MUCH OF THE WEST COAST OF THE CONTIGUOUS U.S. (CONUS). IN THE EAST,
AN AREA OF SURFACE LOW PRESSURE IS FORECAST TO BE DEPARTING THE NORTHEAST WITH
CHANCES FOR STRONG WINDS BEHIND THE SYSTEM. SOME ADDITIONAL PRECIPITATION IS
POSSIBLE IN PARTS OF THE SOUTHEAST BUT IT IS UNLIKELY TO BE HAZARDOUS. QUIETER
WEATHER IS LIKELY ACROSS PARTS OF THE CENTRAL U.S.
HAZARDS
MODERATE RISK OF HEAVY SNOW FOR PORTIONS OF THE NORTHERN SIERRA NEVADA,
KLAMATH, AND SOUTHERN CASCADE MOUNTAINS, SAT-MON, MAR 8-10.
SLIGHT RISK OF HEAVY SNOW FOR THE NORTHERN CASCADE MOUNTAINS FOR FRI-TUE, MAR
7-11.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF NORTHWESTERN OREGON, AND
WESTERN WASHINGTON, FRI-MON, MAR 7-10.
SLIGHT RISK OF HEAVY SNOW FOR MUCH OF THE SIERRA NEVADA, KLAMATH, AND SOUTHERN
CASCADE MOUNTAINS, SAT-WED, MAR 8-12.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF SOUTHWESTERN OREGON AND
CALIFORNIA, SAT-WED, MAR 8-12.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE SOUTHEAST, MID-ATLANTIC,
NORTHEAST, THU-FRI, MAR 6-7.
DETAILED SUMMARY
FOR SATURDAY MARCH 01 - WEDNESDAY MARCH 05:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY MARCH 06 - WEDNESDAY MARCH 12: THERE IS FAIR AGREEMENT AMONG THE
DYNAMICAL MODELS 500-HPA HEIGHT FORECASTS FOR THE WEEK-2 PERIOD ACROSS THE
COUNTRY IN TODAY’S GUIDANCE. A DEEPER AND BROADER TROUGH ACROSS THE EAST IS
FORECAST TO DEVELOP EARLY IN WEEK-2. UPSTREAM OF THIS SYSTEM, AN AREA OF NEAR-
TO ABOVE-NORMAL 500-HPA HEIGHTS IS FORECAST TO BRING TRANSIENT RIDGING TO THE
WESTERN CONUS. A SECOND TROUGH IS FORECAST TO DIG INTO THE WEST COAST BY THE
MIDDLE OF WEEK-2 BRINGING MID-LEVEL ZONAL TO SOUTHERLY FLOW INTO THE WEST.
EARLY IN THE PERIOD, A DEPARTING AREA OF SURFACE LOW-PRESSURE IS FORECAST OVER
THE NORTHEAST AND THE CANADIAN MARITIME PROVINCES. THIS SYSTEM IS A LITTLE
SLOWER AND DEEPER THAN YESTERDAY’S GUIDANCE, INCREASING CHANCES FOR STRONG
WINDS IN THE WAKE OF THE SYSTEM. THEREFORE, A SLIGHT RISK OF HIGH WINDS IS
FORECAST FOR MAR 6 AND 7 ACROSS THE NORTHEAST, MID-ATLANTIC AND INTO PARTS OF
THE SOUTHEAST AND APPALACHIANS. TOOLS ARE FORECASTING A SECONDARY PULSE OF
MOISTURE IN PARTS OF THE SOUTHEAST FOLLOWING THE STRONGER SYSTEM NOW IN WEEK-1.
HOWEVER, AT THIS TIME, PRECIPITATION AMOUNTS DO NOT APPEAR TO REACH HAZARDOUS
THRESHOLDS AND NO CORRESPONDING HAZARD IS POSTED.
IN THE WEST, THE DYNAMICAL GUIDANCE CONTINUES TO FORECAST A NEW SYSTEM TO MOVE
INTO THE REGION BY THE MIDDLE OF THE PERIOD. THE PETS FROM THE GEFS AND ECENS
ARE INDICATING INCREASED CHANCES 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 REMAINS SOME DISAGREEMENT AMONG THE GUIDANCE TODAY WITH THE GEFS 0Z RUN
IN PARTICULAR SHOWING A WEAKER SYSTEM RELATIVE TO YESTERDAY. HOWEVER, THE 6Z
GEFS WAS AGAIN MORE SUPPORTIVE OF A HEAVY PRECIPITATION THREAT. THE ECENS HAS
SHIFTED SLIGHTLY NORTH RELATIVE TO YESTERDAY BRINGING MORE CHANCES FOR HEAVY
PRECIPITATION TO PARTS OF THE PACIFIC NORTHWEST AND SLIGHTLY EARLIER THAN PRIOR
FORECASTS.
THEREFORE, A SLIGHT RISK OF HEAVY SNOW IS POSTED FOR MAR 7-11 ACROSS THE
NORTHERN CASCADE MOUNTAINS. AN ASSOCIATED SLIGHT RISK OF HEAVY PRECIPITATION IS
POSTED FOR MAR 7-10 ACROSS WESTERN WASHINGTON AND NORTHWESTERN OREGON. FURTHER
SOUTH, A SLIGHT RISK OF HEAVY PRECIPITATION REMAINS FORECAST FOR SOUTHWESTERN
OREGON AND NORTHERN AND CENTRAL CALIFORNIA FOR MAR 8-12. AT THIS TIME,
UNCERTAINTY HAS INCREASED ACROSS SOUTHERN CALIFORNIA AND THE HAZARD FORECAST
HAS BEEN DISCONTINUED IN THESE AREAS. A MODERATE RISK OF HEAVY SNOW REMAINS
FORECAST ACROSS PARTS OF THE KLAMATH, SOUTHERN CASCADES, AND NORTHERN
SIERRA-NEVADA FOR MAR 8-10. A BROADER SLIGHT RISK EXTENDING FURTHER SOUTH
ACROSS THE SIERRA-NEVADA IS FORECAST FOR MAR 8-12. ANTICIPATED HEAVIER
PRECIPITATION COULD INCREASE CHANCES OF LOCALIZED FLOODING, PARTICULARLY ACROSS
PORTIONS OF NORTHERN CALIFORNIA. 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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