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FXUS21 KWNC 181128

PMDTHR

US HAZARDS OUTLOOK

NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD

311 PM EDT APRIL 17 2024



SYNOPSIS: ON APRIL 25 AND 26, A STATIONARY FRONT MAY EXTEND EAST 

FROM THE LOWER MISSISSIPPI VALLEY TO THE SOUTHEAST. MID-LEVEL LOW 

PRESSURE IS FORECAST TO REMAIN OVER THE WEST DURING THE FINAL WEEK 

OF APRIL. THIS AREA OF MID-LEVEL LOW PRESSURE FAVORS LOW PRESSURE 

DEVELOPMENT ACROSS THE HIGH PLAINS FROM APRIL 25 TO MAY 1. ALTHOUGH 

THE EXACT TIMING IS UNCERTAIN ON THE STRONGEST WINDS, THERE IS AN 

ELEVATED RISK OF HIGH WINDS FROM THE ROCKIES AND SOUTHWEST EAST TO 

THE GREAT PLAINS THROUGHOUT WEEK-2. ALSO, THE PATTERN WOULD BE 

FAVORABLE FOR THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL FOR MUCH OF 

THE GREAT PLAINS, MIDDLE TO LOWER MISSISSIPPI VALLEY, AND OHIO 

VALLEY.



HAZARDS



SLIGHT RISK OF HIGH WINDS FOR PARTS OF THE SOUTHWEST, ROCKIES, AND 

GREAT PLAINS, THU-WED, APR 25-MAY 1.

SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE GREAT PLAINS, 

MIDDLE TO LOWER MISSISSIPPI VALLEY, AND LOWER OHIO VALLEY, THU-WED, 

APR 25-MAY 1.

FLOODING POSSIBLE ACROSS EASTERN TEXAS AND THE LOWER MISSISSIPPI 

VALLEY.



DETAILED SUMMARY



FOR SATURDAY APRIL 20 - WEDNESDAY APRIL 24: 

HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP



FOR THURSDAY APRIL 25 - WEDNESDAY MAY 1: BY APRIL 25, A STATIONARY 

FRONT IS FORECAST TO EXTEND EITHER ACROSS THE LOWER MISSISSIPPI 

VALLEY OR NORTHERN GULF OF MEXICO. THE DETERMINISTIC 6Z GFS MODEL 

DEPICTS A MORE NORTHERN PLACEMENT OF THIS FRONT WITH A WAVE OF LOW 

PRESSURE TRACKING EAST ALONG IT. CONVERSELY, THE DETERMINISTIC 0Z 

ECMWF MODEL FAVORS THE FRONT PROGRESSING SOUTHWARD INTO THE GULF OF 

MEXICO AND QUICKLY DISSIPATING. IF THE DETERMINISTIC 6Z GFS MODEL 

VERIFIES, THEN THERE WOULD BE AN INCREASED CHANCE OF HEAVY 

PRECIPITATION FOR THE LOWER MISSISSIPPI VALLEY.



DURING THE FINAL WEEK OF APRIL AND THROUGH THE BEGINNING OF MAY, THE 

GFS ENSEMBLE MEAN MAINTAINS A 500-HPA TROUGH OVER THE WEST. THIS 

WOULD CONTINUE TO RESULT IN THE DEVELOPMENT OF SURFACE LOWS TO THE 

LEE OF THE ROCKIES. SHORTWAVE TROUGHS AMPLIFYING OVER THE WEST AND 

THE ASSOCIATED DEVELOPMENT OF SURFACE LOWS ACROSS THE HIGH PLAINS 

SUPPORTS A BROAD SLIGHT RISK AREA OF HIGH WINDS FOR THE SOUTHWEST, 

ROCKIES, AND MUCH OF THE GREAT PLAINS FROM APRIL 25 TO MAY1. IF THE 

GFS AND ECMWF ENSEMBLE MEANS COME INTO BETTER AGREEMENT IN TIMING OF 

SURFACE LOW DEVELOPMENT, THEN A MODERATE RISK OF HIGH WINDS MAY BE 

WARRANTED. ALONG WITH THE OCCASIONAL GUSTY WINDS, THERE IS LIKELY TO 

BE AN ELEVATED WILDFIRE RISK THROUGHOUT THE HIGH PLAINS.



AN UPSTREAM 500-HPA TROUGH, SURFACE LOW DEVELOPMENT ACROSS THE HIGH 

PLAINS, AND ADEQUATE RETURN FLOW FROM THE GULF OF MEXICO ARE 

FORECAST TO PROVIDE A FAVORABLE ENVIRONMENT FOR PERIODS OF 

THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL FROM THE GREAT PLAINS TO 

THE MISSISSIPPI VALLEY DURING WEEK-2. DUE TO TIMING UNCERTAINTY, 

ONLY A SLIGHT RISK OF HEAVY PRECIPITATION IS POSTED AT THIS TIME. 

MINOR TO MODERATE RIVER FLOODING IS ONGOING ACROSS EASTERN TEXAS AND 

THE LOWER MISSISSIPPI VALLEY. SINCE ADDITIONAL RAINFALL (1 TO 3 

INCHES) IS FORECAST PRIOR TO WEEK-2 AND THERE IS AN ELEVATED RISK OF 

HEAVY RAINFALL DURING WEEK-2, A FLOODING POSSIBLE HAZARD IS 

MAINTAINED FOR PARTS OF THESE AREAS.



THE GFS ENSEMBLE MEAN DEPICTS A PERSISTENT 500-HPA TROUGH OVER THE 

ALEUTIANS AND WESTERN ALASKA THROUGH THE ENTIRETY OF WEEK-2. 

ALTHOUGH THIS WOULD FAVOR ENHANCED ONSHORE FLOW INTO SOUTH-CENTRAL 

AND SOUTHEASTERN ALASKA, PRECIPITATION AMOUNTS ARE EXPECTED TO 

REMAIN BELOW HAZARDS THRESHOLDS.



FORECASTER: BRAD PUGH



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