478  
FXUS63 KPAH 171850  
AFDPAH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PADUCAH KY  
150 PM CDT SUN MAY 17 2026  
   
KEY MESSAGES  
 
- BREEZY SOUTH WINDS AND LOTS OF SUN WILL ALLOW TEMPERATURES TO  
CLIMB INTO THE UPPER 80S AND POSSIBLY LOWER 90S THROUGHOUT THE  
QUAD STATE REGION MONDAY AND TUESDAY. MILD LOWS IN THE 60S  
AND 70S ARE EXPECTED.  
 
- A 40-70% CHANCE OF THUNDERSTORMS RETURNS TO THE FORECAST  
MONDAY AFTERNOON, WITH THE BEST CHANCES OVER SOUTHEAST  
MISSOURI AND SOUTHERN ILLINOIS. A FEW SEVERE STORMS WITH A  
DAMAGING WIND AND LARGE HAIL THREAT ARE EXPECTED, ESPECIALLY  
ACROSS SOUTHERN ILLINOIS.  
 
- MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TUESDAY  
AFTERNOON AND NIGHT. AT THIS TIME, SEVERE STORMS CANNOT BE  
RULED OUT, BUT LOCALLY HEAVY RAINFALL WILL DEFINITELY BE A  
CONCERN THROUGH THE PERIOD.  
 
- COOLER CONDITIONS WITH DAILY CHANCES OF SHOWERS AND  
THUNDERSTORMS ARE EXPECTED FOR THE END OF THE WORK WEEK AND  
THE BEGINNING OF THE MEMORIAL DAY WEEKEND. IT LOOKS LIKE IT  
WILL BE WARMING UP THROUGH THE HOLIDAY WEEKEND, WITH DAILY  
CHANCES OF STORMS.  
 
 
   
DISCUSSION  
 
ISSUED AT 150 PM CDT SUN MAY 17 2026  
 
AN ELEVATED MIXED LAYER HAS OVERSPREAD THE QUAD STATE, LEADING  
TO A WARM AND DRY DAY. THE HUMIDITY HAS TAKEN THE DAY OFF OVER  
WEST KENTUCKY AND SOUTHWEST INDIANA WHERE DEWPOINTS HAVE MIXED  
DOWN WELL INTO THE 50S. THE TARGETED LAKE WIND ADVISORY LOOKS  
GOOD FOR TODAY, AND WILL LIKELY BE NEEDED AGAIN MONDAY AND  
POSSIBLY TUESDAY.  
 
THE CAP IS LIKELY TO HOLD THROUGH MUCH OF MONDAY, DESPITE SOME  
MODELS GENERATING SOME QPF OVER VARIOUS PARTS OF THE QUAD STATE.  
HOWEVER, THERE IS A STRONG SIGNAL FOR AN MCS TO REACH THE I-64  
CORRIDOR IN SOUTHERN ILLINOIS AROUND 21Z, AND THE STRONG SOUTH  
WINDS RUNNING INTO ITS OUTFLOW BOUNDARY SHOULD ALLOW IT TO  
DEVELOP SOUTHWARD INTO SOUTHERN ILLINOIS AND SOUTHWEST INDIANA.  
 
MODERATE TO STRONG INSTABILITY IS EXPECTED AHEAD OF THE STORM  
COMPLEX, AND SHEAR WILL BE HEALTHY, TOO, SO SEVERE STORMS ARE  
A DECENT BET, PER THE SLIGHT RISK FROM SPC. GIVEN THE  
INSTABILITY, LARGE HAIL WILL BE A CONCERN, BUT THE 0-3KM SHEAR  
VECTOR WILL BE FROM THE SOUTHWEST, SO DEVELOPMENT INTO OUR  
REGION WILL LIKELY BE UPSHEAR, WHICH IS NOT GOOD FOR MAINTAINING  
AN INTENSE SQUALL LINE AND DAMAGING WIND THREAT. OF COURSE,  
THERE IS ALREADY PLENTY OF UNCERTAINTY JUST IN GETTING THE MCS  
HERE IN THE FIRST PLACE, SO THIS IS ALL VERY CONDITIONAL.  
SUBSEQUENT CHANGES TO THE EXPECTED PATH AND TIMING OF THE MCS  
COULD CHANGE THE SEVERE OUTLOOK ACROSS THE QUAD STATE. IF THE  
MCS MAKES IT AND WE ARE LOOKING AT UPSHEAR DEVELOPMENT, THE  
SLOWER PROGRESSION SOUTHWARD COULD LEAD TO A HEAVY RAINFALL AND  
FLASH FLOODING THREAT GIVEN THE HIGHLY ANOMALOUS PRECIPITABLE  
WATER VALUES EXPECTED.  
 
ANOTHER MCS FROM STORMS THAT FORMED ON THE COLD FRONT WILL  
LIKELY APPROACH THE AREA LATE MONDAY NIGHT, AND SHOULD BE  
WEAKENING SIGNIFICANTLY. THE REMNANT OUTFLOW IS LIKELY TO BE A  
FOCUS FOR THUNDERSTORM DEVELOPMENT IN SOUTHEAST MISSOURI AND  
SOUTHERN ILLINOIS POSSIBLY BEFORE NOON. OF COURSE THERE COULD  
ALSO BE DEVELOPMENT ON THE COLD FRONT APPROACHING FROM THE  
NORTHWEST. THE ENVIRONMENT AHEAD OF THE BOUNDARIES OVER THE QUAD  
STATE SHOULD BE AT LEAST MODERATELY UNSTABLE, BUT THE WIND  
FIELDS SEEM TO BE QUITE MUDDLED WHICH GIVES PAUSE FOR ORGANIZED  
SEVERE POTENTIAL. THE PRECIPITABLE WATER VALUES TUESDAY WILL BE  
IN THE 90TH PERCENTILE OF CLIMATOLOGY OR HIGHER, SO HEAVY  
RAINFALL AND POSSIBLY FLASH FLOODING MAY BE A BIGGER CONCERN  
TUESDAY AND TUESDAY NIGHT.  
 
THE TREND IN GUIDANCE IS TO HAVE THE COLD FRONT THROUGH THE  
ENTIRE AREA BY EARLY WEDNESDAY, SO TEMPERATURES WILL DROP TO  
NORMAL LEVELS OR BELOW FOR WEDNESDAY THROUGH FRIDAY. WE WILL  
REMAIN IN SOUTHWEST OR WEST SOUTHWEST FLOW ALOFT WITH PLENTY OF  
DISTURBANCES IN THAT FLOW STREAMING OVER THE QUAD STATE. THIS  
WILL RESULT IN DAILY CHANCES OF MAINLY AFTERNOON SHOWERS AND  
THUNDERSTORMS. THERE COULD BE SOME STEEP MID-LEVEL LAPSE RATES,  
SO SOME ELEVATED HAIL STORMS CANNOT BE RULED OUT.  
 
LOOKING AHEAD TO THE MEMORIAL DAY WEEKEND, TEMPERATURES WILL BE  
WARMING UP TO NORMAL AND ABOVE THROUGH THE WEEKEND, AND DIURNAL  
THUNDERSTORMS ARE A DECENT BET.  
 
 
   
AVIATION /18Z TAFS THROUGH 18Z MONDAY/  
 
ISSUED AT 1225 PM CDT SUN MAY 17 2026  
 
SOUTH WINDS WILL GUST 18-26KTS THIS AFTERNOON, WITH THE  
STRONGEST WINDS EXPECTED AT KMVN. THERE IS A SMALL CHANCE OF LOW  
MVFR OR EVEN IFR CEILINGS IN THE MORNING, BUT CONFIDENCE IS MUCH  
TOO LOW TO MENTION IN THE FORECAST. AN ISOLATED SHOWER OR  
THUNDERSTORM COULD IMPACT ANY SITE BY THE END OF THE FORECAST.  
SOUTH WINDS WILL INCREASE AGAIN IN THE MORNING AND GUST SIMILAR  
TO THIS AFTERNOON.  
 
 
   
PAH WATCHES/WARNINGS/ADVISORIES  
 
IL...LAKE WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ075-081-  
085.  
MO...LAKE WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MOZ100.  
IN...NONE.  
KY...NONE.  
 
 
 
 
 
DISCUSSION...DRS  
AVIATION...DRS  
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