640
FXUS63 KILX 161742
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1242 PM CDT SUN AUG 16 2026
KEY MESSAGES
- FLOODING CONTINUES ACROSS PORTIONS OF CENTRAL IL IN A CORRIDOR
FROM FULTON AND SOUTHERN KNOX COUNTY TO VERMILION COUNTY DUE
TO 4 TO 7 INCHES OF RAIN THAT FELL YESTERDAY AND ADDITIONAL
RAIN MOVING THROUGH THIS MORNING.
- ADDITIONAL CLUSTERS OF THUNDERSTORMS ARE FORECAST AGAIN LATE
THIS AFTERNOON INTO THE OVERNIGHT HOURS. SPC HAS A SLIGHT
RISK (LEVEL 2 OF 5) SOUTH OF I-70 AND A MARGINAL RISK FOR
AREAS EAST OF THE IL RIVER VALLEY FOR DAMAGING WINDS.
- COOLER AND LESS ACTIVE WEATHER IS ON DECK AFTER TODAY. MONDAY
WILL HAVE HIGHS IN THE 80S AND DRY WEATHER IN PLACE.
UPDATE
ISSUED AT 1047 AM CDT SUN AUG 16 2026
MOST OF THE PRECIP HAS ENDED OR DECREASED SIGNIFICANTLY;
HOWEVER, WIDELY SCATTERED SHOWERS AND T-STORMS WILL CONTINUE
ACROSS MOST OF CENTRAL IL AS A BOUNDARY SLOWLY SHIFTS SOUTH
ACROSS THE AREA THIS AFTERNOON INTO THIS EVENING AND THE
REMNANTS OF AN MCS/MCV MOVE OUT OF NORTHEAST MO INTO IL.
WATCHING THIS MCV OVER MO AND SEVERAL THINGS TO NOTE FOR IT
DECREASING. 1. TOPS HAVE TRENDED WARMER AS IT MOVES EAST. 2.
LIGHTNING HAS DECREASED. 3. CURRENT HIRES GUIDANCE SUGGESTS A
CONTINUING WEAKENING TREND. HOWEVER, THERE ARE TRENDS FOR IT
CONTINUING. 1. HIRES MODELS HAVE BEEN DOING A POOR JOB OVER THE
LAST SEVERAL DAYS, SO CONFIDENCE IN THEM IS NOT AS HIGH AS
DESIRED. 2. IT IS MOVING INTO A MOIST ENVIRONMENT WITH SBCAPE
OVER 3000, MLCAPE AROUND 1000 AND FORECASTED TO BE BETWEEN 1000
AND 1500 THIS AFTERNOON. 3. WEAKENING CIN. 4. MID LEVEL LAPSE
RATES NEAR 6.5 C/KM. AND 5. SATELLITE SHOWING SOME ACCAS AT THE
MID LEVELS IN WEST CENTRAL IL.
SO, SUMMING THIS ALL UP. I THINK THIS CONVECTION WILL CONTINUE
TO MOVE INTO CENTRAL IL AROUND NOON AND CONTINUE INTO THIS
AFTERNOON. SO HAVE INCREASED POPS/WX OVER THIS AREA TO ACCOUNT
FOR SAID CONVECTION, BUT DID TREND TOWARD WEAKENING AS IT MOVE
FURTHER EAST INTO CENTRAL IL AND AS IT CONTINUES EAST DUE TO
INCREASING CLOUD COVER THAT SHOULD LIMIT INSTABILITY THIS
AFTERNOON. HAVE ALSO MADE ADJUSTMENT TO POPS/WX FOR THIS EVENING
INTO TONIGHT AND INCREASED POPS AS BOUNDARY TO NORTH WILL SLOWLY
DROP ACROSS CENTRAL IL. MODELS ARE ALL CONSISTENT WITH
ADDITIONAL CONVECTION DEVELOPING WEST AND MOVING ACROSS CENTRAL
IL THIS EVENING FROM WEST TO EAST, MAINLY ALONG AND SOUTH OF
I-72/DANVILLE.
IN ADDITION, HAVE ALREADY CANCELLED FLOOD WATCH AS NOT
ADDITIONAL FLOODING IS EXPECTED IN THAT AREA. HEAT ADVISORY DOES
CONTINUE IN SOUTHEAST THROUGH EARLY THIS EVENING.
DISCUSSION
ISSUED AT 153 AM CDT SUN AUG 16 2026
TONIGHT MORE SHOWERS AND STORMS WILL BE MOVING ACROSS CENTRAL IL.
THE MAIN CONCERN IS THE FLASH FLOODING RISK. WPC HAS A SMALL AREA OF
EASTERN IL IN A MODERATE RISK (LEVEL 3 OF 4) AND NEAR AND NORTH OF I-
72 IN A SLIGHT RISK (LEVEL 2 OF 4) FOR EXCESSIVE RAINFALL FOR THE
OVERNIGHT HOURS (VALID UNTIL 12Z). THE 00Z SOUNDING SHOWS THE
ENVIRONMENT HAVING PWATS OF 2.2-2.4 INCHES AGAIN. FLOODING IS
ALREADY ONGOING IN MANY PLACES, LEFT OVER FROM LAST NIGHT'S EVENT.
IT WILL NOT TAKE MUCH TO EXACERBATE THE SITUATION OVERNIGHT IF THE
NEW CONVECTION DECIDES TO SET UP OVER THAT STRIPE OF CENTRAL IL
(FULTON CO TO VERMILION CO) AGAIN. LPMM IS SUGGESTING THAT WE COULD
SEE ANOTHER LOCALIZED STRIPE OF 4-8 INCHES SOMEWHERE IN THE AREA
NORTH OF I-72.
THERE IS A SLIGHT RISK (LEVEL 2 OF 5) SOUTH OF I-70 AND A MARGINAL
RISK FOR AREAS EAST OF THE IL RIVER VALLEY FOR DAMAGING WINDS AGAIN
TODAY. THE NAMNEST IS DEPICTING A MORE WIDELY DRY, NEARLY NO
ACTIVITY, SOLUTION. THE HRRR HAS AN AREA OF CONVECTION DEVELOPING
LATE AFTERNOON IN WEST CENTRAL IL, PROGRESSING EASTWARD INTO THE
OVERNIGHT HOURS WITH THE COLD FRONT. AFTER HOW MUCH RAIN NORTH OF I-
70 HAS RECEIVED OVER THE LAST SEVERAL DAYS, THE HOPE IS FOR THE
DRIER SOLUTION, BUT PLAN FOR THE STORMIER SOLUTION. WITH THE HRRR
VERSION OF EVENTS, IT IS SHOWING POCKETS OF 2-4 INCHES OF RAINFALL
FROM 21Z-09Z TODAY INTO TOMORROW. THE GOOD NEWS THOUGH WOULD BE THAT
IF THIS ACTIVITY WERE TO DEVELOP, IT WOULD BE FAIRLY PROGRESSIVE AND
LESS OF A TRAINING SET UP, UNLIKE PREVIOUS DAYS.
TEMPERATURES REMAIN HOT AND HUMID FOR ONE MORE DAY. THE HEAT
ADVISORY FOR SOUTH OF I-70 IS VALID THROUGH 8PM (01Z) THIS EVENING.
HEAT INDICES OF 100-105 DEGREES ARE EXPECTED.
A BRIEF BREAK IN THE ACTIVE WEATHER AND THE HEAT IS LOOKING LIKELY
FOR MONDAY INTO TUESDAY. A HIGH PRESSURE CENTER WILL SET UP OVER THE
UPPER MISSISSIPPI VALLEY / GREAT LAKES REGION BEHIND A COLD FRONT
THAT WILL MOVE THROUGH CENTRAL IL DURING THE DAY TODAY. TEMPERATURES
STARTING MONDAY INTO MUCH OF THE NEXT WEEK WILL BE MAINLY IN THE
UPPER 70S TO 80S FOR HIGHS AND 60S TO LOW 70S FOR LOWS.
MORE SHOWERS AND THUNDERSTORM RE-ENTER THE FORECAST BY TUESDAY
EVENING INTO WEDNESDAY. SPC HAS CENTRAL IL IN A MARGINAL RISK FOR
SEVERE WEATHER FOR TUESDAY WEST OF I-55, WHICH WOULD BE FOR THE LATE
DAY CONVECTION. THERE ARE ADDITIONAL CHANCE FOR RAIN THROUGH
THURSDAY BEFORE RETURNING TO A MOSTLY DRY FORECAST INTO THE
LATE WEEK.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1241 PM CDT SUN AUG 16 2026
AREA OF CONVECTION WILL MOVER ACROSS CENTRAL IL THIS AFTERNOON.
IT SHOULD REMAIN SOUTH OF PIA AND BMI, BUT WILL STILL HAVE VCTS
THERE AND PROB30 GROUPS FOR 3-4HRS AT EACH SITE. SPI, DEC, CMI,
WILL HAVE TEMPO GROUPS FOR THE STORMS WITH THE WORST CONDITIONS
AT SPI WHERE CIGS WILL DROP TO MVFR FOR A BRIEF PERIOD. TEMPO
GROUPS FOR THESE 3 SITES WILL BE 2-3HRS ONLY. ALL SITES SHOULD
SEE A BREAK IN PRECIP BUT WILL KEEP VCSH AT SPI, DEC, AND CMI IN
AFTERNOON FOR COUPLE OF HOURS. MORE PRECIP EXPECTED SPI, DEC,
CMI ONLY IN THE EVENING AND WILL HAVE 4HR PROB30 GROUPS AS THE
FRONT MOVES THROUGH. WINDS WILL BE WESTERLY THIS AFTERNOON AND
THEN BECOME NORTHWESTERLY THIS EVENING BEHIND THE FRONT. LATE
TONIGHT, WINDS SHOULD BECOME MORE NORTHWEST TO NORTHERLY. SPEEDS
WILL BE AROUND 10-15KTS AHEAD OF THE FRONT AND THEN LESS THAN
10KTS BEHIND THE FRONT.
ILX WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ILZ066>068-
071>073.
KEY MESSAGES...COPPLE
UPDATE...AUTEN
DISCUSSION...COPPLE
AVIATION...AUTEN
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