926   
FXUS21 KWNC 181249  
PMDTHR  
  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
312 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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