755  
FXUS63 KILX 181338  
AFDILX  
 
AREA FORECAST DISCUSSION...UPDATED AVIATION  
NATIONAL WEATHER SERVICE LINCOLN IL  
738 AM CST WED DEC 18 2024  
   
KEY MESSAGES
 
 
- LIGHT RAIN IS AFFECTING EAST CENTRAL ILLINOIS THIS MORNING, WITH  
A 10-30% CHANCE OF LIGHT SNOW NORTH OF I-74.  
 
- ANOTHER WEATHER SYSTEM WILL BRING SNOW TO PARTS OF THE REGION  
THURSDAY NIGHT INTO FRIDAY MORNING, THOUGH CURRENT GUIDANCE  
KEEPS MOST OF THE ACCUMULATIONS NORTH OF CENTRAL IL.  
 
- SLIGHTLY ABOVE NORMAL TEMPERATURES THROUGH THURSDAY TREND A FEW  
DEGREES BELOW NORMAL FRI-SUN BEFORE REBOUNDING TO ABOVE NORMAL  
FOR THE COMING HOLIDAY.  
 

 
   
DISCUSSION
 
 
ISSUED AT 252 AM CST WED DEC 18 2024  
 
SHOWERS HAVE MADE THEIR WAY ACROSS CENTRAL ILLINOIS OVERNIGHT INTO  
THIS MORNING. THEY SHOULD COME TO AN END FOR OUR CWA AROUND SUNRISE.  
THERE IS A BAND OF SNOW ASSOCIATED WITH AN AREA OF 700 MB  
FRONTOGENETIC LIFT THAT HAS BEEN OVER PERFORMING ACROSS NORTHERN  
IL OVERNIGHT. DETERMINISTIC CAMS AND GLOBAL MODELS HAVE NOT BEEN  
MUCH HELP THIS MORNING WHEN IT COMES TO DETERMINING IF THIS BAND  
WILL HOLD TOGETHER AND AFFECT OUR MOST NORTHERN COUNTIES. THEY  
AREN'T HANDLING THE EVENT WELL OR INITIALIZING WELL. CURRENTLY,  
TEMPERATURES IN NORTH OF I-72 IN OUR NORTHERN COUNTIES ARE RIGHT  
AROUND THE FREEZING LEVEL, WHICH COULD MEAN A WINTRY MIX IF THE  
BAND DOES REACH DOWN INTO OUR AREA. THE HREF 00Z.18 IS SHOWING A  
10-30% CHANCE OF 0.1 INCH OF SNOW NORTH OF I-74.  
 
AFTER THIS ROUND OF PRECIPITATION EXITS THE AREA BY LATE MORNING,  
THERE WILL BE A LULL IN THE ACTIVITY THROUGH TONIGHT. BY TOMORROW  
MORNING, A CLIPPER SYSTEM WILL MAKE ITS WAY INTO THE MIDWEST. THIS  
BRINGS SOME MORE CHANCES FOR A RAIN/SNOW MIX OVERNIGHT THURSDAY  
BEFORE SWITCHING OVER TO SNOW BY FRIDAY MORNING AS TEMPERATURES COOL  
BEHIND THE ASSOCIATED COLD FRONT. THE EURO, NAM, AND GFS SHOW THE  
SNOW STAYING BARELY NORTH OF THE CWA BUT SOME SNOW COULD CLIP OUR  
NORTH COUNTIES ALONG AND NORTH OF I-74. THAT IS WHERE THE MAIN AREA  
OF SNOW ACCUMULATION IS LOCATED. THERE IS SOME CONCERN FOR FREEZING  
DRIZZLE SOUTH OF THE LOW TRACK WHERE LIFT IS PRESENT BUT MOISTURE IS  
LIMITED.  
 
FINALLY AFTER A VERY ACTIVE PERIOD, WE SEE A BREAK IN THE  
PRECIPITATION LASTING THROUGH MONDAY MORNING. ANOTHER LOW PRESSURE  
SYSTEM LOOKS TO BRING MORE RAIN TO CENTRAL AND SOUTHEASTERN  
ILLINOIS, WITH TEMPERATURES BEING IN THE UPPER 30S TO LOW 40S THAT  
DAY. CHANCES FOR PRECIPITATION CONTINUE INTO CHRISTMAS DAY  
(WEDNESDAY).  
 
TEMPERATURES REMAIN SEASONABLE OR SLIGHTLY ABOVE NORMAL THROUGH  
THURSDAY NIGHT. BEHIND THE CLIPPER SYSTEM FRIDAY, TEMPERATURES COOL  
INTO THE LOW 30S FOR HIGHS AND UPPER TEENS TO LOW 20S FOR LOWS. BY  
SUNDAY, HOWEVER, A REBOUND TO ABOVE NORMAL TEMPERATURES LOOKS  
LIKELY. CHRISTMAS IS 1 WEEK AWAY NOW. A "WHITE" CHRISTMAS IS LOOKING  
LESS LIKELY AS HIGHS AND LOWS ARE FORECAST (CURRENTLY) TO BE ABOVE  
FREEZING.  
 
COPPLE  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)  
ISSUED AT 737 AM CST WED DEC 18 2024  
 
IN THE WAKE OF A NARROW CLEAR SLOT, AN AREA OF IFR/LIFR CEILINGS  
IS DROPPING SOUTHWARD. TIMING TOOLS HAVE IT COMING INTO THE KSPI-  
KCMI CORRIDOR TOWARD 1430Z. THE CLOUD DECK IS ONLY ABOUT 70 MILES  
FROM NORTH TO SOUTH. HOWEVER, HRRR GUIDANCE SUGGESTS AN EXPANSION  
OF THE CLOUD DECK THROUGH LATE MORNING AS WINDS SHIFT MORE TO THE  
NORTHWEST.  
 
UPDATES TO ALL TAF SITES HAVE BEEN SENT.  
 
GEELHART  
 

 
   
ILX WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
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