913
FXUS21 KWNC 201825
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MARCH 20 2026
SYNOPSIS: LINGERING MID-LEVEL HIGH PRESSURE IS DEPICTED OVER THE WESTERN
CONTIGUOUS U.S. (CONUS) EARLY IN THE FORECAST PERIOD, POTENTIALLY EXTENDING
ONGOING UNSEASONABLY WARM TEMPERATURES OVER MUCH OF THE INTERIOR WEST AND
DESERT SOUTHWEST INTO EARLY WEEK-2. SURFACE HIGH PRESSURE IS FAVORED TO BUILD
FROM THE NORTH INTO THE OHIO VALLEY AND MID-ATLANTIC AT THE OUTSET OF WEEK-2,
BRINGING LOWER TEMPERATURES ACROSS THE NORTHEASTERN CONUS AND POTENTIAL FREEZE
CONDITIONS IN AREAS WHERE EMERGING VEGETATION MAY BE VULNERABLE. TIGHT PRESSURE
GRADIENTS ALONG THE WESTERN MARGIN OF SURFACE HIGH PRESSURE OVER THE EASTERN
CONUS BRING THE POTENTIAL FOR ENHANCED WINDS OVER PORTIONS OF THE SOUTHERN AND
CENTRAL PLAINS.
HAZARDS
SLIGHT RISK OF MUCH ABOVE-NORMAL TEMPERATURES FOR PORTIONS OF THE DESERT
SOUTHWEST, GREAT BASIN, AND CALIFORNIA, SAT-SUN, MAR 28-29.
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR PORTIONS OF THE MID-ATLANTIC,
SOUTHERN APPALACHIANS, AND TENNESSEE VALLEY, SAT-SUN, MAR 28-29.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS,
SAT-WED, MAR 28-APR 1.
DETAILED SUMMARY
FOR MONDAY MARCH 23 - FRIDAY MARCH 27:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR SATURDAY MARCH 28 - FRIDAY APRIL 03: ENSEMBLE MEAN 500-HPA HEIGHT ANOMALY
FORECASTS FROM THE 0Z ECENS AND GEFS ARE IN REASONABLE AGREEMENT THROUGH ABOUT
THE MIDDLE OF WEEK-2, AND DEPICT AMPLIFIED RIDGING OVER THE WEST EARLY IN
WEEK-1, WHICH THEN WEAKENS AND SHIFTS EASTWARD BY THE MIDDLE OF THE FORECAST
PERIOD AS TROUGHING BEGINS TO EMERGE OVER THE NORTH PACIFIC. AT THIS POINT THE
ENSEMBLE SOLUTIONS DIVERGE SIGNIFICANTLY, WITH THE ECENS INDICATING A
SHORTWAVE TROUGH EMERGING AND MOVING OVER THE INTERIOR WEST BY THE MIDDLE OF
WEEK-2, WHILE THE GEFS PREFERS A STRONGER TROUGH OVER THE NORTH PACIFIC WITH
SLOWER EASTWARD PROGRESSION. REGARDLESS OF THE EVOLUTION OF THE PACIFIC TROUGH,
ITS DEVELOPMENT AND THE CONCURRENT SHIFT EASTWARD OF RIDGING OVER THE DESERT
SOUTHWEST RESULTS IN A MODERATION OF TEMPERATURES AFTER AN UNUSUALLY EARLY HEAT
WAVE OVER MUCH OF THE WEST. THAT SAID, RECORD-BREAKING HIGH TEMPERATURES ARE
STILL INDICATED BY THE NATIONAL BLEND OF MODELS FOR MARCH 28-29 ACROSS MANY
LOCATIONS IN THE SOUTHWESTERN CONUS. THIS IS FURTHER SUPPORTED BY THE ECENS AND
GEFS PROBABILISTIC EXTREMES TOOLS (PETS), WHICH BOTH INDICATE AT LEAST A 20%
CHANCE OF HIGH TEMPERATURES TO EXCEED THE 85TH CLIMATOLOGICAL PERCENTILE FOR
THE SAME DAYS, WARRANTING A CONTINUATION OF A SLIGHT RISK FOR MUCH ABOVE-NORMAL
TEMPERATURES ACROSS PORTIONS OF THE DESERT SOUTHWEST, GREAT BASIN, AND
CALIFORNIA FOR MARCH 28-29.
MEANWHILE, BOTH THE ECENS AND GEFS 500-HPA HEIGHT ANOMALIES DEPICT DEEP
TROUGHING OVER HUDSON BAY AND STRONG CYCLONIC FLOW OVER THE YUKON EARLY IN
WEEK-2, PROVIDING UPPER-LEVEL SUPPORT FOR A COLD SURGE TO MOVE INTO THE EASTERN
CONUS. THESE FEATURES QUICKLY DEAMPLIFY LEADING TO A RAPID MODERATION OF COLD
TEMPERATURES, BUT UNCALIBRATED DAILY MINIMUM TEMPERATURE FORECASTS REACH NEAR
TO BELOW FREEZING AS FAR SOUTH AS THE MID-ATLANTIC AND TENNESSEE VALLEY. THIS
IS FURTHER SUPPORTED BY THE ECENS PET, WHICH SHOWS A 20% CHANCE OF MINIMUM
TEMPERATURES FALLING BELOW FREEZING AT THE OUTSET OF THE FORECAST PERIOD. THE
GEFS IS LESS BULLISH BUT STILL SHOWS SOME MODEST SIGNAL FOR POTENTIAL
SUB-FREEZING TEMPERATURES. WHILE THIS DOES NOT MEET COLD-WEATHER CRITERIA,
GIVEN THE TIME OF YEAR, SUCH CONDITIONS MAY BE DAMAGING TO EMERGING VEGETATION.
THEREFORE, A SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES REMAINS POSTED FOR
PORTIONS OF THE MID-ATLANTIC, SOUTHERN APPALACHIANS, AND TENNESSEE VALLEY FOR
MAR 28-29.
THE COLD SURGE DESCRIBED ABOVE IS ACCOMPANIED BY A STRONG SURFACE HIGH PRESSURE
CENTER THAT MOVES ACROSS THE OHIO VALLEY AND MID-ATLANTIC DURING THE FORECAST
PERIOD. BOTH THE ECENS AND GEFS DEPICT SHARP PRESSURE GRADIENTS ALONG THE
WESTERN MARGIN OF THIS FEATURE FOR MUCH OF THE FORECAST PERIOD, ALONG WITH
POTENTIAL LEE CYCLOGENESIS LATER IN WEEK-2. THIS IS FAVORED TO RESULT IN HIGH
WINDS OVER MUCH OF THE SOUTHERN AND CENTRAL PLAINS, WHERE BOTH THE GEFS AND
ECENS INDICATE WINDS OFTEN NEARING OR EXCEEDING 20MPH. THERE IS LESS SUPPORT
FROM THE PETS REGARDING HIGH WIND, BUT SYNOPTIC PATTERN RECOGNITION ALONG WITH
MODELED MEAN WIND SPEEDS WARRANTS A SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF
THE SOUTHERN AND CENTRAL PLAINS, VALID MAR 28-APR 1.
OVER HAWAII, PERSISTENT KONA LOW ACTIVITY HAS LED TO HEAVY RAINFALL AND
FLOODING THROUGHOUT THE STATE. ENSEMBLES DO NOT SHOW MUCH CHANGE IN THE
MID-LEVEL PATTERN WITH TROUGHING FAVORED TO PERSIST OVER THE CENTRAL PACIFIC
LATER IN MARCH. PETS CONTINUE TO INDICATE ELEVATED CHANCES FOR 3-DAY AMOUNTS
EXCEEDING THE 85TH PERCENTILE, WITH 3-DAY TOTAL ACCUMULATIONS EXCEEDING AN INCH
FOR SOME LOCATIONS THROUGHOUT WEEK-2. THE CONTINUATION OF ABOVE-NORMAL AND
POTENTIALLY HEAVY PRECIPITATION IS LIKELY TO WORSEN ALREADY SATURATED GROUND
CONDITIONS AND MAY TRIGGER ADDITIONAL LOCALIZED FLOODING IN THE STATE.
FORECASTER: DANNY BARANDIARAN
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