239  
FXUS63 KILX 020037  
AFDILX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE LINCOLN IL  
737 PM CDT THU OCT 1 2026  
   
KEY MESSAGES  
 
- MULTIPLE ROUNDS OF WIDESPREAD RAIN WILL TRACK ACROSS THE  
REGION THROUGH FRIDAY MORNING. BROAD RAINFALL TOTALS AROUND  
ONE INCH ARE EXPECTED, THOUGH LOCALIZED HEAVY RAIN BANDS COULD  
PRODUCE ISOLATED AMOUNTS OF 2 TO 4 INCHES.  
 
- TEMPERATURES DROP SIGNIFICANTLY HEADING INTO THE WEEKEND,  
WITH HIGHS FROM THE MID 60S TO AROUND 70 FRIDAY AND SATURDAY,  
AND OVERNIGHT LOWS FALLING INTO THE 40S.  
 
- DRY CONDITIONS AND SEASONABLY COOL TEMPERATURES LOOK TO  
CONTINUE NEXT WORK WEEK.  
 
 
   
UPDATE  
 
ISSUED AT 737 PM CDT THU OCT 1 2026  
 
A SIGNIFICANT INCREASE IN RAIN COVERAGE HAS BEEN OCCURING OVER  
THE PAST COUPLE HOURS. PREVIOUSLY A BIT SLOW IN MAKING ITS  
PUSH EAST FROM THE ILLINOIS RIVER, THE LEADING EDGE HAS REACHED  
I-55, WITH MORE SCATTERED ACTIVITY FURTHER EAST ALONG A SURFACE  
BOUNDARY. OUR EVENING SOUNDING SHOWED PRECIPITABLE WATER VALUES  
AT 2 INCHES, CLOSE TO RECORD TERRITORY FOR EARLY OCTOBER.  
RAINFALL RATES AROUND A HALF INCH PER HOUR ARE CURRENTLY  
OCCURRING JUST WEST OF I-55, THOUGH LIGHTNING ACTIVITY HAS BEEN  
FAIRLY NON-EXISTENT RECENTLY. REFS PRECIPITABLE WATER  
PROJECTIONS SHOW THE 2+ INCH PW'S PERSISTING OVER CENTRAL  
ILLINOIS FOR CENTRAL ILLINOIS FOR A FEW MORE HOURS, GRADUALLY  
SHIFTING TOWARD THE I-70 CORRIDOR BY MIDNIGHT. WHILE 1-HOUR  
FLASH FLOOD GUIDANCE NEAR I-55 IS IN THE 2-2.5 INCH RANGE, ANY  
HEAVY RAIN WITH TRAINING ECHOES MAY LEAD TO SOME PONDING OF  
WATER IN POOR DRAINAGE AREAS.  
 
 
   
DISCUSSION  
 
ISSUED AT 145 PM CDT THU OCT 1 2026  
 
A COLD FRONT LOCATED NEAR THE MISSISSIPPI RIVER THIS AFTERNOON WILL  
CONTINUE TO SHIFT EASTWARD OVERNIGHT AS AN UPPER LEVEL TROUGH OVER  
THE REGION PROGRESSES EASTWARD, INGESTING AN UPPER LEVEL LOW AND  
REMNANT MOISTURE FROM FORMER TROPICAL SYSTEM POLO. 12Z SOUNDINGS IN  
THE SOUTHERN PLAINS REFLECT OVER 2 INCHES OF PRECIPITABLE WATER,  
WHICH LENDS CREDENCE TO LOCALIZED ACCUMULATIONS OF RAINFALL OF  
2 TO 4 INCHES SHOWN IN A FEW HIGH-RES MODELS BY FRIDAY MORNING.  
AMOUNTS OF THIS RANGE WOULD REQUIRE NEARLY STATIONARY CORRIDORS  
OF MULTIPLE ROUNDS OF SHOWERS OR THUNDERSTORMS (TRAINING).  
NEVERTHELESS, MOST AREAS CAN EXPECT ONE HALF TO ONE INCH  
AMOUNTS. A FEW THUNDERSTORMS WILL ALSO BE POSSIBLE THROUGH  
TONIGHT GIVEN LOW VALUES OF CAPE FORECAST, ALTHOUGH RECENTLY  
HAVE NOT DETECTED ANY LIGHTNING FROM SHOWERS AROUND THE IL RIVER  
AND WESTWARD.  
 
PRECIPITATION SHOULD COME TO AN END BY SUNRISE FROM I-55  
NORTHWESTWARD, BUT COULD LINGER PAST NOON FROM I-70 SOUTHWARD.  
NEVERTHELESS, DRY CONDITIONS WILL BE IN PLACE ACROSS THE AREA BY  
FRIDAY NIGHT AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE  
NORTHWEST. HIGH PRESSURE WILL REMAIN DOMINANT THROUGH NEXT WEEK,  
ALTHOUGH A FEW DRY COLD FRONTS COULD MODULATE TEMPERATURES.  
HIGHS SHOULD REACH ONLY MID 60S TO AROUND 70 FRIDAY AND SATURDAY,  
WARM A BIT FOR SUNDAY WITH LOWER TO MID 70S, THEN COOL BACK TO  
AROUND 70 FOR MONDAY AND TUESDAY FOLLOWING A FRONT SUNDAY.  
TEMPERATURES WARM A BIT WEDNESDAY AND THURSDAY TO MID AND UPPER 70S.  
AFTER LOWS STILL FAIRLY MILD IN MUCH OF THE AREA TONIGHT, WITH UPPER  
50S TO MID 60S EAST OF I-55 AND LOWER TO MID 50S TO THE WEST, LOWS  
SHOULD GENERALLY BE SEASONABLY COOL WITH 40S TO AROUND 50 THE NEXT  
SEVERAL DAYS.  
 
 
   
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/  
 
ISSUED AT 622 PM CDT THU OCT 1 2026  
 
INITIAL WIND SHIFT FROM S/SE TO NW IS CURRENTLY ABOUT TO ENTER  
KDEC AND WILL REACH EASTERN ILLINOIS EARLY THIS EVENING, WHILE A  
MORE SUBSTANTIAL INCREASE IN SPEEDS OCCUR LATER THIS EVENING AS  
WINDS BECOME NORTH. WHILE SHOWERS IN EASTERN ILLINOIS HAVE BEEN  
MORE SCATTERED THUS FAR, A MORE SUBSTANTIAL AREA OF RAIN WILL  
SHIFT SOUTHEAST ACROSS THE TERMINALS THROUGH THE EVENING,  
LINGERING WELL PAST MIDNIGHT IN EASTERN ILLINOIS. THIS WILL BE  
ACCOMPANIED BY A PERIOD OF IFR CEILINGS OF 600-900 FEET, AND  
POTENTIAL FOR HEAVIER SHOWERS REDUCING VISIBILITY BELOW 2 MILES.  
VFR CEILINGS SHOULD RETURN AT KPIA AROUND 08-09Z, REACHING  
KDEC/KCMI TOWARD 12-13Z OR SO.  
 
 
   
ILX WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
 
KEY MESSAGES...37  
UPDATE...GEELHART  
DISCUSSION...37  
AVIATION...GEELHART  
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