550  
FXUS01 KWBC 201914  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
314 PM EDT MON MAY 20 2024  
 
VALID 00Z TUE MAY 21 2024 - 00Z THU MAY 23 2024  
 
...CONTINUED SEVERE WEATHER AND EXCESSIVE RAINFALL THREATS OVER  
PARTS OF THE CENTRAL U.S. INTO MID-WEEK...  
 
...COOL CONDITIONS WITH PERIODS OF SHOWER AND HIGH ELEVATION SNOW  
CHANCES FROM THE ROCKIES TO THE PACIFIC NORTHWEST...  
 
...WELL ABOVE AVERAGE AND SUMMER-LIKE TEMPERATURES TO START THE  
WEEK FROM THE CENTRAL/SOUTHERN PLAINS TO THE NORTHEAST...  
 
AN ENERGETIC UPPER-LEVEL PATTERN FEATURING MULTIPLE SHORTWAVES  
EMITTING FROM A BROADER LONG-WAVE TROUGH OVER THE WESTERN U.S.  
WILL CONTINUE A PERIOD OF ACTIVE WEATHER THROUGHOUT THE CENTRAL  
U.S. THIS WEEK. SHOWERS AND THUNDERSTORMS ARE ALREADY PUSHING  
EASTWARD ACROSS THE GREAT LAKES THIS AFTERNOON AHEAD OF A LEADING  
SYSTEM OVER THE UPPER MIDWEST. BY TONIGHT, A DEVELOPING SURFACE  
CYCLONE OVER THE CENTRAL HIGH PLAINS IN RESPONSE TO A DEEPER  
SHORTWAVE EJECTING INTO THE PLAINS WILL SPARK NUMEROUS  
THUNDERSTORMS FROM NORTHEAST COLORADO THROUGH NEBRASKA AND IOWA.  
THESE STORMS MAY CONTAIN DAMAGING WIND GUSTS, LARGE HAIL, AND A  
FEW TORNADOES, WHICH HAS PROMPTED AN ENHANCED RISK (LEVEL 3/5) FOR  
SEVERE THUNDERSTORMS FROM NORTHEAST COLORADO TO CENTRAL NEBRASKA.  
HEAVY RAIN MAY ALSO LEAD TO SCATTERED INSTANCES OF FLASH FLOODING  
TONIGHT FOR PARTS OF IOWA. THIS LOW PRESSURE SYSTEM IS EXPECTED TO  
REMAIN COMPACT AND STRENGTHEN AS IT PROGRESSES INTO THE UPPER  
MIDWEST ON TUESDAY. ONCE AGAIN THE THREAT OF SEVERE WEATHER AND  
HEAVY RAIN WILL BE ASSOCIATED WITH THIS SYSTEM THROUGHOUT THE  
MIDWEST AND GREAT LAKES. THUNDERSTORMS ARE EXPECTED ALONG AND  
AHEAD OF A COLD FRONT AS IT EXTENDS SOUTHWARD INTO THE SOUTHERN  
PLAINS, WITH WIDESPREAD MODERATE TO HEAVY RAIN NORTH OF A WARM  
FRONT INCLUDING PARTS OF MINNESOTA, WISCONSIN, AND NORTHERN IOWA.  
THE STORM PREDICTION CENTER HAS ISSUED A MODERATE RISK (LEVEL 4/5)  
FOR SEVERE THUNDERSTORMS FROM SOUTH-CENTRAL IOWA TO NORTHWEST  
ILLINOIS IN ORDER TO CAPTURE THE THREAT OF DAMAGING WIND GUSTS AND  
THE POTENTIAL FOR A FEW STRONG TORNADOES. AS THE AFOREMENTIONED  
LOW SHIFTS INTO SOUTHWESTERN ONTARIO WEDNESDAY MORNING  
(POTENTIALLY AT RECORD STRENGTH FOR THE MONTH OF MAY) AND THE  
ATTACHED COLD FRONT SLIDES INTO THE MID-SOUTH AND SOUTHERN PLAINS,  
HEAVY RAINFALL REMAINS A CONCERN WHERE THIS FRONTAL BOUNDARY COMES  
TO A CRAWL. A SLIGHT RISK (LEVEL 2/4) OF EXCESSIVE RAINFALL IS IN  
EFFECT BETWEEN NORTHEAST TEXAS AND EASTERN OKLAHOMA TO THE LOWER  
OHIO VALLEY AS THUNDERSTORMS COULD BE SLOW-MOVING AND CONTAIN  
INTENSE RAINFALL RATES.  
 
COOL AND UNSETTLED WEATHER UNDERNEATH THE BROAD UPPER TROUGH IS  
ANTICIPATED TO REMAIN LOCKED-IN OVER THE NORTHWEST AND ROCKIES  
THROUGH AT LEAST MIDWEEK. SNOW IS POSSIBLE INTO THE HIGHER  
ELEVATIONS OF WYOMING AND COLORADO ON TUESDAY BEFORE WINTER  
WEATHER CHANCES ENTER THE NORTHERN ROCKIES ON WEDNESDAY, WITH SNOW  
LEVELS POSSIBLY DROPPING TO AROUND 7000 FEET. HIGH TEMPERATURES IN  
THESE REGIONS ARE ALSO EXPECTED TO REMAIN ON THE COOLER SIDE AND  
10 TO 25 DEGREES BELOW AVERAGE.  
 
MEANWHILE, FOR AREAS SOUTH AND EAST OF THE MAIN STORM SYSTEM  
IMPACTING THE CENTRAL U.S. THIS WEEK, HIGHS ARE EXPECTED TO SOAR  
ABOVE AVERAGE AND INTO POTENTIALLY RECORD-BREAKING TERRITORY FOR  
CERTAIN SPOTS. WIDESPREAD HIGHS INTO THE 80S AND LOW 90S ARE  
FORECAST FROM THE MIDWEST AND DEEP SOUTH TO THE NORTHEAST THROUGH  
WEDNESDAY, WITH MID-TO-UPPER 90S AND TRIPLE DIGITS IN PARTS OF  
SOUTH TEXAS AND THE SOUTHERN HIGH PLAINS. THIS HEAT COULD BE  
PARTICULARLY DANGEROUS FOR PEOPLE DEALING WITH A LOSS OF POWER IN  
PARTS OF TEXAS. WARM OVERNIGHT TEMPERATURES WILL OFFER LITTLE  
RELIEF AND HIGH HUMIDITY COULD ALSO LEAD TO HEAT INDEX READINGS  
OVER 110 DEGREES.  
 
SNELL  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  
 

 
 
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