179  
FXUS63 KILX 262339  
AFDILX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE LINCOLN IL  
639 PM CDT FRI JUL 26 2024  
   
KEY MESSAGES
 
 
- DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS FROM SATURDAY NIGHT  
THROUGH MUCH OF NEXT WEEK.  
 
- HOT AND HUMID CONDITIONS ARRIVE MONDAY THROUGH THURSDAY WITH  
AFTERNOON HEAT INDICES OF 100 OR HIGHER POSSIBLE WEST OF THE IL  
RIVER MONDAY AFTERNOON, AND ACROSS CENTRAL AND SOUTHEAST IL  
DURING THE AFTERNOON AND EARLY EVENING HOURS FROM TUESDAY  
THROUGH THURSDAY.  
 

 
   
DISCUSSION
 
 
ISSUED AT 330 PM CDT FRI JUL 26 2024  
 
MID AFTERNOON SURFACE ANALYSIS SHOWS WEAK 1023 MB HIGH PRESSURE  
OVER THE CENTRAL GREAT LAKES AND RIDGING INTO CENTRAL AND  
NORTHEAST IL. THIS WAS PROVIDING A FAIR AMOUNT OF SUNSHINE OVER  
CENTRAL IL WHILE MORE CUMULUS CLOUDS AND HIGH CLOUDS SEEN OVER  
WEST CENTRAL AND SOUTHERN/SOUTHEAST IL. TEMPERATURES WERE MOSTLY  
IN THE LOWER 80S AT 3 PM WITH SOME UPPER 70S FROM BLOOMINGTON AND  
PARIS NORTHEAST. MORE COMFORTABLE DEWPOINTS IN THE UPPER 50S AND  
LOWER 60S FROM PEORIA, DECATUR AND MATTOON NE WHILE MORE MUGGY  
DEWPOINTS IN THE UPPER 60S/LOWER 70S FROM GALESBURG TO SPRINGFIELD  
TO FLORA SW. ALOFT A 590+ DM 500 MB SKINNY RIDGE WAS OVER THE  
WESTERN PARTS OF THE CENTRAL AND SOUTHERN PLAINS AND ARCHING INTO  
THE UPPER MS RIVER VALLEY. 500 MB HEIGHTS OVER IL WERE 588-590 DM,  
HIGHEST NEAR THE IOWA BORDER.  
 
FAIR WEATHER EXPECTED TONIGHT ACROSS CENTRAL AND SOUTHEAST IL  
UNDER INFLUENCE OF NEARBY HIGH PRESSURE DRIFTING SLOWLY EASTWARD  
OVER THE GREAT LAKES REGION. SOME FOG EXPECTED OVER SOUTHERN/SW IL  
MAINLY SOUTH OF CWA OVERNIGHT INTO EARLY SAT MORNING WHERE  
DEWPOINTS/AIRMASS MORE MOIST. LOWS TONIGHT MOSTLY IN THE LOWER  
60S, WITH SOME UPPER 50S FROM BMI AND CMI NE AND NEAR 65F FROM  
HIGHWAY 50 SOUTH WHERE MORE CLOUD COVER OVER AND HIGHER  
DEWPOINTS.  
 
DEVELOPING SOUTHEAST FLOW AROUND BACK SIDE OF SURFACE HIGH  
PRESSURE ON SATURDAY TO BRING DEWPOINTS UP INTO THE MID TO UPPER  
60S SAT AFTERNOON AND MAY SEE AN ISOLATED SHOWER OR THUNDERSTORMS  
SW OF A SPRINGFIELD TO EFFINGHAM LINE BY LATE SAT AFTERNOON.  
CLOUDS WILL ALSO BE INCREASING FROM THE SOUTH DURING SAT AFTERNOON  
AND SAT NIGHT WITH TROPICAL MOISTURE ADVECTED INTO THE AREA.  
SEASONABLE HIGHS SATURDAY IN THE MID 80S IN CENTRAL IL AND UPPER  
80S SE OF I-70. POPS INCREASE TO 20-30% DURING SAT NIGHT  
ESPECIALLY OVERNIGHT SAT NIGHT AS TROPICAL PLUME OF MOISTURE  
CONTINUES TO STREAM NORTHWARD OVER IL AHEAD OF APPROACHING WEAK  
UPPER LEVEL LOW/TROF MOVING INTO CENTRAL IA/MO BY SUNDAY MORNING.  
MILDER LOWS IN THE UPPER 60S TO AROUND 70F.  
 
HAVE LIKELY CHANCES OF SHOWERS AND ISOLATED THUNDERSTORMS OVER CWA  
ON SUNDAY, WITH HIGHEST POPS AND QPF IN EASTERN/SE IL AS TROPICAL  
MOISTURE CONTINUES TO STREAM NORTHWARD AHEAD OF WEAK UPPER LEVEL  
TROF MOVING INTO THE MS RIVER VALLEY BY LATE SUNDAY AFTERNOON.  
RAINFALL AMOUNTS OVERNIGHT SAT NIGHT INTO SUNDAY IS A QUARTER TO  
HALF INCH WITH LOCALLY HIGHER AMOUNTS ESPECIALLY IN EASTERN IL AND  
NW OF THE IL RIVER. SPC DAY3 OUTLOOK KEEPS MARGINAL RISK WEST OF  
IL FOR SUNDAY AFTERNOON/EVENING. MORE CLOUDS AND SHOWERS ON SUNDAY  
TO KEEP HIGHS A BIT COOLER THAN SATURDAY WITH HIGHS SUNDAY IN THE  
LOW TO MID 80S. MORE HUMID AS DEWPOINTS GET IN THE LOW TO MID 70S  
WITH SOUTHERLY FLOW.  
 
UPPER LEVEL RIDGE BUILDING INTO IL FROM MONDAY INTO WED TO BRING  
CENTRAL/SE IL A HEAT WAVE MUCH OF THIS WORK WEEK. HIGHS IN THE MID  
TO UPPER 80S MONDAY WITH DEWPOINTS IN THE 70S GIVING AFTERNOON  
HEAT INDICES IN THE MID TO UPPER 90S EAST OF THE IL RIVER AND  
AROUND 100F WEST OF THE IL RIVER. TUE THROUGH THU LIKELY SEE HIGHS  
IN THE LOWER 90S WITH DEWPOINTS IN THE 70S, WITH AFTERNOON HEAT  
INDICES OF 98-110F. WE MAY EVENTUALLY NEED A HEAT ADVISORY FOR  
PART OF OUR AREA DURING MID WEEK BUT WE ARE ALSO LOOKING AT A FEW  
MORE ROUNDS OF SHOWERS AND THUNDERSTORMS WITH POSSIBLE MCS  
ACTIVITY OVER TOP OF THE RIDGE. MONDAY AFTERNOON AND MONDAY NIGHT  
LOOKS LIKE A HIGH CHANCE OF CONVECTION. ANOTHER ENHANCE CHANCE OF  
CONVECTION WED AFTERNOON AND WED NIGHT. SPC DOES NOT HAVE ANY  
SEVERE RISK OVER CENTRAL/SE IL THIS UPCOMING WEEK. BUT THE CPU  
MACHINE LEARNING HAS SOME RISK FROM MONDAY THROUGH MID WEEK. SOME  
UPPER LEVEL TROF DIGGING INTO IL LATE THIS WEEK TO KEEPING  
CHANCES OF CONVECTION AROUND ALONG WITH TEMPS GETTING CLOSER TO  
NORMAL WITH HIGHS IN THE MID TO UPPER 80S NEXT FRIDAY AND  
SATURDAY, THOUGH STILL HUMID WITH DEWPOINTS LIKELY IN THE LOWER  
70S NEXT FRIDAY.  
 
 
07  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)  
ISSUED AT 638 PM CDT FRI JUL 26 2024  
 
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. A LITTLE  
BIT OF CIRRUS WILL BE POSSIBLE THIS EVENING, BUT THIN ENOUGH TO  
NOT WARRANT A MENTION. SO, WILL GO CLEAR SKIES THROUGH THE NIGHT.  
CU COULD DEVELOP TOMORROW AS THINGS CHANGE SO HAVE SCATTERED CU  
AROUND 4KFT TOMORROW FROM LATE MORNING THROUGH AFTERNOON. WIND  
WILL BE LIGHT AND VARIABLE THROUGH THE NIGHT THEN BECOME SOUTHEAST  
AROUND 8KTS TOMORROW.  
 
AUTEN  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
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