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FXUS21 KWNC 311819
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MARCH 31 2026
SYNOPSIS: THE RETURN OF DEVELOPING MID-LEVEL LOW (HIGH) PRESSURE ACROSS THE
WESTERN (EASTERN) CONTIGUOUS U.S. (CONUS) INCREASES CHANCES FOR HAZARDOUS
PRECIPITATION AND HIGH WINDS MAINLY ACROSS THE GREAT PLAINS AND MISSISSIPPI
VALLEY LATER NEXT WEEK. EARLY IN WEEK-2, MID-LEVEL LOW PRESSURE IS EXPECTED TO
BRING BELOW-NORMAL TEMPERATURE ACROSS THE NORTHEASTERN CONUS, WHERE THERE ARE
INCREASED CHANCES FOR NEAR AND/OR SUBFREEZING TEMPERATURES TO POTENTIALLY
IMPACT EMERGING SPRINGTIME VEGETATION IN PARTS OF THE OHIO VALLEY.
HAZARDS
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE SOUTHERN AND CENTRAL
PLAINS, MIDDLE AND LOWER MISSISSIPPI VALLEY AND ADJACENT AREAS OF THE OHIO
VALLEY, FRI-SUN, APR 10-12.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE GREAT BASIN, CENTRAL AND SOUTHERN
ROCKIES, AND PLAINS, THU-SAT, APR 9-11.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE OHIO VALLEY, WED, APR 8.
DETAILED SUMMARY
FOR FRIDAY APRIL 03 - TUESDAY APRIL 07:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR WEDNESDAY APRIL 08 - TUESDAY APRIL 14: SINCE YESTERDAY, DYNAMICAL MODEL
500-HPA HEIGHT FORECASTS HAVE DEVELOPED SLIGHTLY MORE AMPLIFIED 500-HPA RIDING
CENTERED OVER THE GREAT PLAINS BY THE MIDDLE OF NEXT WEEK, WHILE CONTINUING TO
MAINTAIN A PAIR OF SHORTWAVE TROUGHS OVER THE EASTERN CONUS AND ALONG THE WEST
COAST. TOWARDS THE END OF NEXT WEEK, BOTH THE GEFS AND ECMWF ENSEMBLES ARE IN
AGREEMENT PROGRESSING THE RIDGE CENTER EASTWARD WHILE STRENGTHENING OVER THE
NORTHEASTERN CONUS, ALLOWING FOR THE DEVELOPMENT OF DEEPER TROUGHING OVER THE
INTERIOR WEST. SUCH A TRANSITION REMAINS FAVORABLE FOR SURFACE LOW DEVELOPMENT
IN THE LEE OF THE ROCKIES, INCREASING CHANCES FOR POTENTIALLY HEAVY
PRECIPITATION AND EPISODES OF HIGH WINDS ACROSS THE PLAINS AND MISSISSIPPI
VALLEY. BY AROUND DAY 12 (APR 12), THE ECMWF AND GEFS ENSEMBLES BEGIN TO
DIVERGE IN REGARDS TO EVOLUTION OF THE MID-LEVEL PATTERN MAINLY WEST OF THE
MISSISSIPPI. THE ECMWF BUILDS IN MORE RIDGING ACROSS THE INTERIOR WEST, WHEREAS
THE GEFS FAVORS MORE PERSISTENCE OF THE TROUGHING AND CYCLONIC FLOW DOWNSTREAM
OF ANOTHER RIDGE ANOMALY CENTER OVER THE NORTHEASTERN PACIFIC. AS A RESULT,
THERE IS INCREASED UNCERTAINTY WITH THE REEMERGENCE OF ANY HEAVY PRECIPITATION
AND HIGH WIND THREATS ACROSS THE CENTRAL CONUS LATER IN APRIL.
DURING DAYS 8-10 (APR 8-10), BOTH THE GEFS AND ECMWF ENSEMBLES SHOW SURFACE
HIGH PRESSURE SHIFTING EASTWARD ACROSS THE NORTHEASTERN CONUS IN THE WAKE OF A
FRONTAL SYSTEM LATE IN WEEK-1. WHILE A BRIEF PERIOD OF COOLER TEMPERATURES ARE
FAVORED FOR THE NORTHEASTERN CONUS, THIS SURFACE FEATURE LOOKS TO BRING THE
RESUMPTION OF RETURN FLOW FROM THE GULF AND ADVECT LOWER-LEVEL MOISTURE BACK
INTO THE PLAINS AND MISSISSIPPI VALLEY. BASED ON THE ORIENTATION OF THE MEAN
SURFACE FLOW, THE DEEPEST MOISTURE ADVECTION AND ACCOMPANYING POSITIVE
PRECIPITATION WATER ANOMALIES APPEAR MOST CONCENTRATED OVER THE GREAT PLAINS IN
ADVANCE OF A DEVELOPING SURFACE LOW. CURIOUSLY, SINCE OFTEN ATYPICAL OF THE
MODELS AT THIS LEAD, THE GEFS IS STRONGER WITH THE SURFACE LOW AND FAVORS
HIGHER CHANCES OF PRECIPITATION EXCEEDANCE THAN THE ECMWF IN THE UNCALIBRATED
TOOLS BEGINNING BY DAY 10 (APR 10). THOUGH, BETTER AGREEMENT EXISTS BETWEEN THE
CALIBRATED GEFS AND ECMWF PROBABILISTIC EXTREMES TOOLS (PETS), BOTH DEPICTING
AT LEAST 20% CHANCES FOR 3-DAY AMOUNTS EXCEEDING THE 85TH CLIMATOLOGICAL
PERCENTILE AND 1 INCH FROM THE RIO GRANDE OF SOUTHERN TEXAS TO THE MIDDLE
MISSISSIPPI VALLEY SUPPORTIVE OF THE CONTINUATION OF A SLIGHT RISK OF HEAVY
PRECIPITATION, VALID FOR APR 8-10. SHOULD THE ECMWF ENSEMBLE DEVELOP A STRONGER
MEAN SURFACE LOW IN SUBSEQUENT ENSEMBLE RUNS, A CORRESPONDING MODERATE RISK IS
LIKELY TO BE CONSIDERED FOR ADDITION IN THE HAZARD OUTLOOKS LATER THIS WEEK.
WITHIN THE HIGHLIGHTED RISK AREA, THERE IS A THREAT OF THUNDERSTORM ACTIVITY,
PARTICULARLY ACROSS PARTS OF OKLAHOMA AND TEXAS WHERE DETERMINISTIC SOLUTIONS
SHOW THE RETURN OF ELEVATED DEWPOINTS REACHING THE UPPER 60S AND LOWER 70S (DEG
F), WITH A SHARP DRYLINE GRADIENT TAKING SHAPE ACROSS THE SOUTHERN PLAINS.
AT THE BASE AND AHEAD OF THE DEVELOPING, AND POTENTIALLY DEEPENING MID-LEVEL
TROUGH, EPISODES OF HIGH WINDS LOOK TO ONCE AGAIN BE A CONCERN. DESPITE THE
WEAKER MEAN SURFACE LOW IN THE ECMWF, ITS PET INDICATES AT LEAST 20% CHANCES
FOR WIND SPEEDS EXCEEDING THE 85TH PERCENTILE, AND THE UNCALIBRATED ECMWF AND
GEFS TOOLS SHOW INCREASED CHANCES FOR WIND GUSTS EXCEEDING 34 KNOTS (40 MPH)
OVER THE PLAINS AND MISSISSIPPI VALLEY PRIOR TO THE HEAVY PRECIPITATION RISK.
THEREFORE, A SLIGHT RISK OF HIGH WINDS IS POSTED FOR APR 9-11, BEFORE SURFACE
PRESSURE GRADIENTS EASE AGAIN BY THE MIDDLE OF THE PERIOD. WITH ANOMALOUS
WARMTH FAVORED FOR THE PLAINS LEADING UP TO INCREASED WIND RISK, ANY EPISODES
OF HIGH WINDS ARE EXPECTED TO PROMOTE FIRE WEATHER THROUGH MUCH OF THIS REGION
INTO THE MIDDLE OF WEEK-2, PARTICULARLY IN AREAS NOT HAVING REGISTERED ANY
ABOVE-NORMAL RAINFALL IN RECENT WEEKS.
UNSEASONABLY WARM SPRINGTIME TEMPERATURES ARE ALSO LIKELY TO ACCOMPANY THE
EVOLVING 500-HPA RIDGE CENTER. THIS IS LIKELY TO CONSIST OF COOLING (WARMING)
TEMPERATURES ACROSS THE WESTERN (EASTERN) CONUS THROUGHOUT THE PERIOD. HOWEVER,
PRIOR TO THE FAVORED WARMUP IN THE EASTERN U.S., THERE IS INCREASED SUPPORT IN
THE TEMPERATURE TOOLS FOR NEAR TO SUBFREEZING TEMPERATURES OVER PARTS OF THE
OHIO VALLEY TIED TO SHORTWAVE TROUGHING ALOFT BY THE OUTSET OF THE PERIOD.
ALTHOUGH THE ECMWF PET IS WEAKER WITH THE SOUTHERN EXTENT OF THE ANOMALOUS COLD
AIR OVER THE EASTERN U.S, THE GEFS PET AS WELL AS THE UNCALIBRATED GEFS AND
ECMWF TEMPERATURE TOOLS INDICATE INCREASED CHANCES FOR NEAR TO SUB FREEZING
TEMPERATURES ACROSS PARTS OF THE OHIO VALLEY WHERE SPRING EMERGING VEGETATION
LOOKS TO BE SUSCEPTIBLE TO FROST AND/OR FREEZES. THEREFORE, A SLIGHT RISK OF
MUCH BELOW NORMAL TEMPERATURES IS POSTED FOR DAY 8 (APR 8) BEFORE TEMPERATURES
ARE FAVORED TO QUICKLY MODERATE AS THE RIDGING ALOFT MOVES IN. AS FOR ANY
HAZARDOUS WARMTH, TOOLS ARE NOT SUPPORTIVE OF TEMPERATURES REACHING THE
UNPRECEDENTED WARMTH THAT WAS FELT ACROSS THE WEST EARLIER THIS MONTH, NOR ANY
DAYTIME TEMPERATURES REACHING HEAT LEVEL CRITERIA.
NO HAZARDS ARE ISSUED OVER ALASKA. WARMING TEMPERATURES ARE ALSO PREDOMINATELY
FAVORED TIED TO POSITIVE HEIGHT DEPARTURES EXPANDING EASTWARD FROM THE BERING
STRAIT INTO PARTS OF THE MAINLAND. THIS TEMPERATURE TREND FOLLOWS A PROLONGED
PERIOD OF BELOW NORMAL TEMPERATURES FELT THROUGHOUT THE STATE THIS WINTER, AS
ANY DRASTIC WARMUP COMBINED WITH RAPIDLY INCREASING SUN ANGLES OVER THE HIGHER
LATITUDES MAY ACCELERATE SPRINGTIME THAWS.
ACROSS HAWAII, PERSISTENT KONA LOW ACTIVITY BROUGHT HEAVY RAINFALL AND FLOODING
DURING MID-MARCH. ENSEMBLE GUIDANCE SHOWS THE RETURN OF AN APPROACHING
MID-LEVEL TROUGH TO THE NORTH OF THE ISLAND CHAIN, WHICH MAY TRIGGER ADDITIONAL
KONA LOW ACTIVITY AND RENEW THE RISK OF HEAVY PRECIPITATION DURING THE PERIOD.
PETS SHOW INCREASED CHANCES FOR 3-DAY AMOUNTS EXCEEDING THE 85TH PERCENTILE
THROUGH THE MIDDLE OF WEEK-2, HOWEVER THE HIGHEST PRECIPITATION AMOUNTS (3-DAY
AMOUNTS GREATER THAN 1 INCH) ARE FAVORED OFFSHORE AT THIS TIME. ANY HEAVY
PRECIPITATION DURING WEEK-2 MAY WORSEN ALREADY SATURATED GROUND CONDITIONS, AND
POSSIBLY TRIGGER FLOODING IN THE STATE.
FORECASTER: NICK NOVELLA
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