138
FXUS63 KILX 150720
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
220 AM CDT SAT AUG 15 2026
KEY MESSAGES
- THERE IS FLASH FLOODING ONGOING ACROSS PORTIONS OF CENTRAL
ILLINOIS THIS MORNING, WHERE THUNDERSTORMS TRACK OVER AREAS
THAT HAVE ALREADY SEEN 4-6 INCHES OF RAIN SINCE THURSDAY.
AREAS NORTH OF A HAVANA TO BLOOMINGTON LINE ARE MOST AT RISK.
- STORMS HAVE THE POTENTIAL TO PRODUCE DAMAGING WINDS TODAY AND
TOMORROW. SPC HAS A MARGINAL (LEVEL 1 OF 5) RISK OF SEVERE
WEATHER FOR THE WEEKEND.
- THE HEAT AND HUMIDITY REMAIN A CONCERN FOR THE WEEKEND, WITH
THE HOTTEST CONDITIONS IN THE SOUTHERN HALF OF THE STATE.
DISCUSSION
ISSUED AT 220 AM CDT SAT AUG 15 2026
TONIGHT, STORMS ARE MOVING ACROSS CENTRAL IL. THERE IS A LOW RISK
(BUT NON-ZERO) FOR DAMAGING WINDS WITHIN THESE STORMS, BUT THE MAIN
CONCERN IS THE FLASH FLOODING RISK. WPC HAS AREAS NEAR AND NORTH OF
I-72 IN A MODERATE RISK (LEVEL 3 OF 4) FOR EXCESSIVE RAINFALL FOR
THE OVERNIGHT HOURS. THE 00Z SOUNDING SHOWS THE ENVIRONMENT HAVING
PWATS OF 2.2-2.4 INCHES. OVER THE LAST FEW DAYS, THIS AREA HAS
GOTTEN 3-6 INCHES OF RAIN, WITH SOME LOCALLY HIGHER AMOUNTS. THE
STORMS PASSING THROUGH TONIGHT ARE EXPECTED TO DROP ANOTHER 2-5
INCHES WITH THE LPMM SUGGESTING SOME LOCALIZED POCKETS OF UP TO 10
INCHES. FLASH FLOOD GUIDANCE SEEMS A BIT GENEROUS (TOO HIGH). IF THE
POCKETS OF HIGHER RAIN SET UP OVER WHERE THE GROUND IS ALREADY
EXTREMELY SATURATED, FLASH FLOODING IS LIKELY.
FOR THE REMAINDER OF THE DAY AFTER THIS MORNING ROUND OF CONVECTION
EXITS ABOUT 15-16Z, THERE IS A MARGINAL RISK FOR SEVERE WEATHER FOR
ADDITIONAL ACTIVITY THAT WILL MOVE THROUGH. IT WILL BE VERY SIMILAR
TO WHAT HAS HAPPENED OVER THE LAST FEW DAYS. THE NEXT ROUND OF MCS
ACTIVITY WILL MOVE INTO CENTRAL IL BY LATE EVENING AND WILL CONTINUE
INTO THE OVERNIGHT HOURS. THE MAIN CONCERN WILL BE DAMAGING WINDS
AND THE HEAVY RAIN POTENTIAL.
THERE IS ANOTHER MARGINAL RISK FOR SEVERE WEATHER AGAIN TOMORROW FOR
AREAS SOUTH OF A SCHUYLER TO MCLEAN COUNTY LINE WITH A SIMILAR
ENVIRONMENT IN PLACE AS PREVIOUS DAYS. THE FORECAST WILL CONTINUE TO
EVOLVE AS WE GET NEWER RUNS OF THE MODELS.
TEMPERATURES REMAIN HOT AND HUMID. THE HEAT ADVISORY FOR SOUTH OF I-
70 IS VALID THROUGH SUNDAY. HEAT INDICES OF 100-110 DEGREES ARE
FORECAST THROUGH SUNDAY, BUT HOW FAR NORTH THESE HEAT INDICES GET
WILL DEPEND SOLELY ON THE CONVECTION LOCATION. LIKE YESTERDAY FOR
EXAMPLE, THE CONVECTION LINGERED FURTHER SOUTH LONGER THAN FORECAST,
SO HEAT INDICES STRUGGLED TO HIT TRIPLE DIGITS.
NEXT WEEK MAY BRING US A BRIEF BREAK IN THE ACTIVE WEATHER AND THE
HEAT BRIEFLY. A HIGH PRESSURE AREA WILL SET UP OVER THE UPPER
MISSISSIPPI VALLEY / GREAT LAKES REGION BY MONDAY, BEHIND A COLD
FRONT THAT WILL MOVE THROUGH CENTRAL IL DURING THE DAY. 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.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1223 AM CDT SAT AUG 15 2026
THUNDERSTORMS ARE MOVING ACROSS PORTIONS OF CENTRAL ILLINOIS DURING
THE EARLY OVERNIGHT HOURS AND EXPECTED TO CONTINUE INTO SATURDAY
MORNING BEFORE EXITING EAST OF THE AREA. MVFR/IFR CEILINGS CURRENTLY
IN PLACE NORTH OF THE TERMINALS WILL SINK SOUTH TO ALONG THE I-74
CORRIDOR OVERNIGHT, BUT CONFIDENCE IS CURRENTLY LOW THAT IT WILL
REACH AS FAR SOUTH AS SPI/DEC. AREAS THAT DO DROP ARE EXPECTED TO
IMPROVE BACK TO VFR EARLY TO MID SATURDAY AFTERNOON AS WINDS VEER TO
SWERLY.
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR ILZ027>031-
036>038-040-041-043>046-055-057.
HEAT ADVISORY UNTIL 8 PM CDT SUNDAY FOR ILZ066>068-071>073.
KEY MESSAGES...COPPLE
DISCUSSION...COPPLE
AVIATION...DEUBELBEISS
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