704
FXUS21 KWNC 091951
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MARCH 09 2026
SYNOPSIS: THERE IS A LINGERING POTENTIAL FOR ENHANCED ONSHORE FLOW OVER THE
PACIFIC NORTHWEST, WHICH MAY BRING HEAVY PRECIPITATION AMOUNTS TO PORTIONS OF
WESTERN WASHINGTON, ALONG WITH HIGH ELEVATION SNOWFALL AND HIGH WINDS FOR THE
INTERIOR NORTHWESTERN CONTIGUOUS U.S. (CONUS). STRONG MID-LEVEL HIGH PRESSURE
SITUATED OVER THE GREAT BASIN IS EXPECTED TO PROMOTE UNSEASONABLY WARM
TEMPERATURES FOR MUCH OF THE SOUTHWESTERN U.S., AS WELL AS AN INCREASED RISK OF
SANTA ANA WINDS FOR SOUTHERN CALIFORNIA LATER NEXT WEEK. EAST OF THE ROCKIES,
MID-LEVEL LOW PRESSURE IS FAVORED TO STRENGTHEN OVER THE EASTERN CONUS,
RESULTING IN A PERIOD OF COLDER THAN NORMAL TEMPERATURES, WHERE NEAR TO
SUBFREEZING TEMPERATURES MAY ADVERSELY IMPACT EMERGING EARLY SPRING VEGETATION
FOR PARTS OF THE GULF STATES EARLY IN THE PERIOD. PERSISTENT MID-LEVEL HIGH
PRESSURE TO THE WEST OF THE BERING STRAIT IS EXPECTED TO BRING A PROLONGED
PERIOD OF BELOW NORMAL AND POTENTIALLY IMPACTFUL TEMPERATURES FOR MUCH OF
ALASKA.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE PACIFIC NORTHWEST, TUE-THU, MAR
17-19.
SLIGHT RISK OF HEAVY SNOW OVER THE NORTHERN CASCADES, TUE-THU, MAR 17-19.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE COAST OF WASHINGTON AND NORTHWEST
OREGON, TUE-WED, MAR 17-18.
SLIGHT RISK OF HIGH WINDS OVER MOST OF THE NORTHERN AND CENTRAL ROCKIES AND
INTO THE GREAT PLAINS, TUE-WED, MAR 17-18.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF SOUTHERN CALIFORNIA, TUE-FRI, MAR
17-20.
SLIGHT RISK OF MUCH ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE SOUTHWESTERN
CONUS, TUE-SAT, MAR 17-21.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE LOWER
MISSISSIPPI AND TENNESSEE VALLEYS, AND THE SOUTHEAST, TUE-THU, MAR 17-19.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES OVER MUCH OF SOUTHERN AND WESTERN
MAINLAND ALASKA AND PARTS OF THE SOUTHEAST, TUE-MON, MAR 17-23.
SLIGHT RISK OF HIGH WINDS OVER THE SOUTHERN COAST OF ALASKA AND SOUTHEAST
ALASKA, TUE-MON, MAR 17-23.
POSSIBLE FLOODING FOR PORTIONS OF THE WHITE RIVER VALLEY IN INDIANA.
DETAILED SUMMARY
FOR THURSDAY MARCH 12 - MONDAY MARCH 16:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR TUESDAY MARCH 17 - MONDAY MARCH 23: DYNAMICAL MODEL 500-HPA HEIGHT
FORECASTS FROM THE ECMWF AND GEFS ENSEMBLES CONTINUE TO FAVOR AMPLIFIED
MID-LEVEL RIDGING OVER THE WESTERN CONUS, WITH STRONG NEGATIVE HEIGHT
DEPARTURES OVER THE HIGHER LATITUDES OF CANADA CONSISTENT WITH THE POSITIVE
PHASE OF THE ARCTIC OSCILLATION (AO) PATTERN OVER NORTH AMERICA. SINCE
YESTERDAY, THESE ENSEMBLES HAVE GROWN STRONGER WITH THE RIDGE ANOMALY CENTER
OVER THE GREAT BASIN, INCLUDING A NORTHWARD EXPANSION OF THE MEAN POSITIVE
HEIGHT DEPARTURES INTO SOUTHWESTERN CANADA RESULTING IN PREDOMINATELY DRIER
SOLUTIONS FOR THE NORTHWESTERN CONUS AS ENHANCED ONSHORE FLOW LOOKS TO BE
SHUNTED TO THE NORTH DURING THE PERIOD. DOWNSTREAM, A 500-HPA TROUGH REMAINS
FAVORED TO DIG INTO CENTRAL AND EASTERN CONUS EARLY IN WEEK-2, WITH THE ECMWF
ENSEMBLE DEPICTING A DEEPER TROUGH AXIS EXTENDING INTO THE SOUTHEASTERN U.S.
EARLY NEXT WEEK COMPARED TO PREVIOUS GUIDANCE. AS A RESULT, A COLDER
TEMPERATURE RESPONSE IS GENERALLY DEPICTED IN THE TEMPERATURE TOOLS MAINLY EAST
OF THE MISSISSIPPI, HOWEVER A MODERATION OF TEMPERATURES IS FAVORED AS THIS
TROUGHING LIFTS OUT LATER IN WEEK-2. OVER ALASKA, A STRONG RIDGE SITUATED TO
THE WEST OF THE BERING STRAIT IS FAVORED TO PERSIST THROUGHOUT THE PERIOD,
WHERE DOWNSTREAM NORTHERLY FLOW IS EXPECTED TO BRING BELOW NORMAL TEMPERATURES
THROUGHOUT THE PERIOD FOR THE ENTIRE STATE.
WITH STRONGER MID-LEVEL RIDGING FAVORED IN THE LATEST ENSEMBLES ACROSS THE
WEST, THERE IS A SUBSTANTIAL REDUCTION IN TOTAL PRECIPITATION AMOUNTS IN BOTH
THE RAW AND CALIBRATED TOOLS RELATIVE TO YESTERDAY. ALTHOUGH THE INTEGRATED
VAPOR TRANSPORT (IVT) TOOLS CONTINUE TO HIGHLIGHT ELEVATED CHANCES FOR AMOUNTS
EXCEEDING 250 KG/M/S, WHICH WOULD BE SUPPORTIVE OF CONTINUING A MODERATE RISK
OF HEAVY PRECIPITATION, THIS RISK DESIGNATION IS DISCONTINUED IN THE UPDATED
OUTLOOK BASED ON GOOD AGREEMENT IN THE UNCALIBRATED TOOLS DEPICTING WEAKER
CHANCES (<30%) FOR 3-DAY AMOUNTS EXCEEDING 2 INCHES ACROSS PORTIONS OF WESTERN
WASHINGTON. HOWEVER, A SLIGHT RISK OF HEAVY PRECIPITATION REMAINS ISSUED, ALONG
WITH A SLIGHT RISK OF HIGH ELEVATION HEAVY SNOW FOR THE CASCADES BOTH VALID FOR
MAR 17-19 GIVEN THE POTENTIAL FOR ANY ENHANCED ONSHORE FLOW TO LINGER INTO THE
WEEK-2 PERIOD. A SLIGHT RISK OF HIGH WINDS ALSO REMAINS POSTED (MAR 17-18) OVER
COASTAL PORTIONS OF WASHINGTON AND OREGON, AS WELL AS OVER THE DOWNSLOPE
REGIONS OF THE NORTHERN AND CENTRAL ROCKIES WHERE THE PROBABILISTIC EXTREMES
TOOL (PET) MAINTAINS AT LEAST A 20% CHANCE OF WIND SPEEDS EXCEEDING THE 85TH
PERCENTILE AS ENHANCED PACIFIC FLOW INTO THE ROCKIES MAY BRING CHANCES FOR
EPISODES OF HIGH WINDS.
THE STRONG MID-LEVEL RIDGING CENTERED OVER THE GREAT BASIN ALSO SUPPORTS AN
INCREASED RISK OF OFFSHORE FLOW AND SANTA ANA WINDS FOR PORTIONS OF SOUTHERN
CALIFORNIA. WHILE ENSEMBLES ARE NOT PARTICULARLY BULLISH WITH THE DEVELOPMENT
OF SURFACE HIGH PRESSURE OVER THE FOUR CORNERS, THERE ARE BETTER INDICATIONS
FOR THE DEVELOPMENT OF THERMALLY INDUCED LOW PRESSURE IN THE SONORAN DESERT TO
SUPPORT THIS SETUP. THEREFORE, A SLIGHT RISK OF HIGH WINDS IS POSTED FOR
PORTIONS OF SOUTHERN CALIFORNIA THROUGH MIDDLE OF WEEK-2 BEFORE MUCH OF THE
RIDGING IS FAVORED TO DEAMPLIFY. ACCOMPANYING THIS WIND POTENTIAL IS AN
INCREASED LIKELIHOOD FOR MUCH ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE
SOUTHWESTERN CONUS. NOTABLY, THE NATIONAL BLEND OF MODELS (NBM) SHOWS SEVERAL
LOCATIONS NEARING RECORD BREAKING DAYTIME TEMPERATURES FROM THE CALIFORNIA
VALLEY (UPPER 80S DEG F) INTO THE LOWER FOUR CORNERS (LOWER 100S DEG F) EARLY
IN THE PERIOD. WHILE TEMPERATURES ARE NOT QUITE WARM ENOUGH IN THE SONORAN
DESERT TO SUPPORT AN EXTREME HEAT HAZARD, THE ANOMALOUSLY WARM TEMPERATURES MAY
CONTRIBUTE TO AN EARLY ONSET OF HIGH ELEVATION SNOWMELT WHERE SNOWPACK HAS BEEN
WELL BELOW NORMAL ACROSS THE WEST. SNOWMELT IS ALREADY EXPECTED TO
SIGNIFICANTLY INCREASE THIS WEEK AND LEAD TO INCREASED FLOWS AND AFFECTED
RIVERS. THEREFORE, A SLIGHT RISK OF MUCH ABOVE NORMAL TEMPERATURES IS POSTED
(MAR 17-21) FOR MUCH OF THE SOUTHWESTERN CONUS UNDER THE ANOMALOUS RIDGE CENTER
AND WHERE PETS SHOW ELEVATED CHANCES FOR MAXIMUM TEMPERATURES EXCEEDING THE
98TH PERCENTILE THROUGH THE MIDDLE OF WEEK-2.
IN THE WAKE OF A LOW PRESSURE SYSTEM LIFTING OUT OVER THE NORTHEAST LATE IN
WEEK-1, AN AREA OF STRONG MEAN SURFACE HIGH PRESSURE AND THE ACCOMPANYING
ANOMALOUS COLD AIR IS FAVORED TO DESCEND FROM THE CANADIAN PRAIRIES AND
OVERSPREAD MUCH OF THE EASTERN U.S. WITH COLDER AND DRIER CONDITIONS FAVORED IN
ADDITION TO ENSEMBLES FAVORING THE DEPARTING LOW TO BE WELL OFF THE CANADIAN
MARITIMES EARLY IN WEEK-2, THE SLIGHT RISKS OF HEAVY PRECIPITATION, HEAVY SNOW,
AND HIGH WINDS ARE DISCONTINUED OVER THE NORTHEAST IN THE UPDATED OUTLOOKS AS
THESE THREATS LOOK TO HAVE TIMED OFF. HOWEVER, DUE TO THE DEEPER TROUGHING
FAVORED ALOFT IN THE ECMWF AND GEFS, THERE IS BETTER SUPPORT IN THE TEMPERATURE
TOOLS FOR COLDER TEMPERATURES DIGGING FARTHER SOUTH INTO THE SOUTHEAST WHERE
PETS SHOW ELEVATED CHANCES (20-30%) OF MINIMUM TEMPERATURES FALLING BELOW THE
15TH CLIMATOLOGICAL PERCENTILE AND BELOW FREEZING. WHILE SUCH TEMPERATURES ARE
NOT EXPECTED TO BE EXTREMELY COLD, SUCH A COOLDOWN FOLLOWS A VERY WARM WEEK-1
ACROSS THE SOUTHEASTERN CONUS, WHERE THE POSSIBLE RETURN OF FROST AND FREEZES
MAY BE A SHOCK TO ANY EMERGING SPRING VEGETATION FOR THE LOWER LATITUDES OF THE
CONUS. THEREFORE, A SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES IS POSTED
FROM THE LOWER MISSISSIPPI VALLEY TO THE CAROLINAS FOR FEB 17-19. COLDER
TEMPERATURES, WITH INCREASED CHANCES FOR NIGHTTIME MINIMUMS TO FALL INTO THE
TEENS ARE FAVORED FURTHER NORTH ACROSS THE DAKOTAS, GREAT LAKES AND THE
NORTHEAST, THOUGH ACTUAL TEMPERATURES ARE EXPECTED TO REMAIN ABOVE EXTREME COLD
CRITERIA FOR THESE REGIONS.
A FLOODING POSSIBLE HAZARD REMAINS IN PLACE ACROSS PORTIONS OF THE WHITE RIVER
VALLEY IN INDIANA FOR THE PERIOD AS A RESULT OF ANTECEDENT PRECIPITATION AND
ONGOING FLOODING. MORE THAN 5 INCHES OF PRECIPITATION HAS FALLEN OVER PARTS OF
INDIANA IN THE PAST WEEK AND THE WEATHER PREDICTION CENTER'S DAY 1-7 FORECAST
PREDICTS ANOTHER 1-2 INCHES OVER THIS REGION DURING WEEK-1. WHILE CONDITIONS
ARE EXPECTED TO TREND DRIER DURING WEEK-2, ANY ADDITIONAL PRECIPITATION MAY
WORSEN GROUND CONDITIONS DURING THE OUTLOOK PERIOD.
OVER ALASKA, ANOMALOUS 500-HPA RIDGING WEST OF THE BERING STRAIT WITH
DOWNSTREAM TROUGHING OVER THE MAINLAND AND GULF OF ALASKA IS FAVORED TO PERSIST
THROUGHOUT WEEK-2, PROLONGING THE INCREASED LIKELIHOOD OF BELOW NORMAL
TEMPERATURES LATER IN MARCH. PETS CONTINUE TO HIGHLIGHT INCREASED CHANCES FOR
MINIMUM TEMPERATURES FALLING BELOW THE 15TH PERCENTILE, SUPPORTING A SLIGHT
RISK OF MUCH BELOW NORMAL TEMPERATURES, NOW VALID FOR PORTIONS OF THE
SOUTHEAST, SOUTHERN AND WESTERN MAINLAND FOR ALL OF WEEK-2. STRONG MEAN LOW
PRESSURE IN THE GULF OF ALASKA ALSO SUPPORTS THE CONTINUATION OF A SLIGHT RISK
OF HIGH WINDS (MAR 17-23), WHERE COMBINED WITH COLDER TEMPERATURES, FREEZING
SEA SPRAY REMAINS A CONCERN DURING THE PERIOD.
OVER THE CENTRAL PACIFIC, MID-LEVEL TROUGHING AND ASSOCIATED KONA LOW
DEVELOPMENT ARE FAVORED TO BRING POTENTIALLY RAINFALL TO THE HAWAIIAN ISLANDS
DURING WEEK-2, WHICH IS REFLECTED IN BOTH THE GEFS AND ECMWF PETS. WHILE ACTUAL
3-DAY TOTALS HAVE LESSENED IN THESE TOOLS COMPARED TO EARLIER GUIDANCE, THIS
THREAT OF HEAVY PRECIPITATION LOOKS TO PERSIST WITH LITTLE INDICATION OF
DRYNESS LATER IN MARCH.
FORECASTER: NICK NOVELLA
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