513
FXUS63 KILX 040510
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1210 AM CDT SAT JUL 4 2026
KEY MESSAGES
- A HEAT ADVISORY IS IN EFFECT THROUGH 7 PM SATURDAY FOR MUCH
OF CENTRAL AND SOUTHEAST IL.
- ISOLATED SEVERE STORMS MAY DEVELOP THIS EVENING. WHILE
WIDESPREAD SEVERE WEATHER IS UNLIKELY, ANY STORM COULD PRODUCE
LOCALIZED TORRENTIAL RAINFALL AND BRIEF, DAMAGING WIND GUSTS.
- A FRONT WILL PUSH THROUGH THE REGION ON SUNDAY, BRINGING A
WELCOME END TO THE HEAT WAVE. COOLER, LESS HUMID, AND DRY
CONDITIONS ARE FORECAST MONDAY THROUGH WEDNESDAY.
UPDATE
ISSUED AT 825 PM CDT FRI JUL 3 2026
LINEAR COMPLEX OF STORMS FROM EASTERN IA INTO NORTHERN IL, WILL
SHIFT SOUTHEAST ACROSS NORTHERN PORTIONS OF THE ILX CWA LATER
THIS EVENING AND OVERNIGHT. THE AIRMASS AHEAD OF THE STORMS IS
FORECAST TO REMAIN MODERATELY UNSTABLE WITH MLCAPES OF 2000-3000
J/KG WELL INTO THE OVERNIGHT. EFFECTIVE DEEP LAYER SHEAR WILL BE
MARGINAL FOR SEVERE STORMS AROUND 20-25 KT. SO SEVERAL STRONG
STORMS AND AN ISOLATED DAMAGING WIND GUST OR TWO COULD BE SEEN
TONIGHT, PARTICULARLY NORTH OF I-74 IN A 10 PM TO 2 AM WINDOW.
PWATS AROUND 1.9" WILL LEAD TO HIGH RAINFALL RATES UP TO
1-2"/HR.
DISCUSSION
ISSUED AT 230 PM CDT FRI JUL 3 2026
HIGH HEAT AND HUMIDITY...
THE EXTREME HEAT WARNING FOR CWA GOES UNTIL 7 PM TODAY WITH
DANGEROUS HEAT INDICES PEAKING FROM 100-110, HIGHEST ALONG AND
SOUTHEAST OF A MACOMB TO PONTIAC LINE WHERE LESS CONVECTION HAS
OCCURRED SO FAR TODAY. THE HEAT ADVISORY FROM 11 AM TO 7 PM ON
SATURDAY HAS BEEN EXPANDED NORTHWARD TO INCLUDE THE REST OF THE
CWA EXCEPT FOR KNOX, STARK AND MARSHALL COUNTIES. SOME
CONVECTION THAT AFFECTED AREAS NW OF THE IL RIVER PAST 1-2 HOURS
HAS COOLED TEMPS AND HEAT INDICES OVER KNOX, STARK AND MARSHALL
COUNTIES BUT STARTING TO HEAT BACK UP WITH GALESBURG HEAT INDEX
UP TO 97F AND LACON HEAT INDEX UP TO 96F AND HEAT INDICES MAY
WARM BACK UP TO NEAR 100F LATE THIS AFTERNOON OVER NORTHERN 3
COUNTIES. WE ARE FORECASTING HIGHS BACK TO AROUND 90F TO LOWER
90S SATURDAY WITH AFTERNOON HEAT INDICES PEAKING FROM 100-105,
HIGHEST IN SOUTHEAST IL. HEAT INDICES STILL AROUND 100F IN
SOUTHEAST IL ON SUNDAY AFTERNOON WHILE LOW TO MID 90S FROM I-72
NORTH. WE MAY NEED TO HAVE ANOTHER HEAT ADVISORY SUNDAY
AFTERNOON FOR SOUTHEAST IL DUE TO THE DURATION OF THIS HEAT WAVE
SINCE THIS PAST SUNDAY JUNE 28TH.
CONVECTIVE POTENTIAL & SEVERE RISKS...
SEVERE THUNDERSTORM WATCH WAS POSTED THIS AFTERNOON UNTIL 7 PM
OVER NORTHEAST IL FROM LASALLE, LIVINGSTON, FORD AND IROQUOIS
COUNTIES NORTHEAST. MORE WIDESPREAD THUNDERSTORMS, WITH SOME
STRONG TO POTENTIALLY SEVERE HAVE BEEN IN NORTHEAST IL WITH A
FEW STRONG CELLS EARLIER PASSING THROUGH EASTERN MARSHALL AND
NORTHERN WOODFORD COUNTIES BETWEEN 120-2 PM WITH GUSTY WINDS AND
POSSIBLE SMALL HAIL. CURRENT RADAR MOSAIC SHOWS ISOLATED CELLS
NW OF THE IL RIVER AND ALONG A ST LOUIS TO TAYLORVILLE TO
DECATUR TO DANVILLE LINE. MORE CONVECTION WAS OVER SOUTHERN
INDIANA INTO WESTERN KY AND FAR SOUTHERN IL. SPC DAY1 OUTLOOK
HAS MARGINAL RISK OF SEVERE STORMS, WITH SLIGHT RISK NORTH OF A
CANTON TO BLOOMINGTON LINE FOR THIS AFTERNOON AND INTO THIS
EVENING. PRIMARY SEVERE WX RISK IS DAMAGING WINDS (15%) WITH 5%
RISK OF LARGE HAIL IN SLIGHT RISK AREA OVER NORTHERN CWA. VERY
UNSTABLE AIRMASS WITH ML CAPES OF 3-4K J/KG WHILE WEAK EFFECTIVE
BULK SHEAR VALUES LESS THAN 25 KTS OVER ALL BUT FAR NORTHERN 3
COUNTIES WHERE ITS 25-30 KTS FROM GALESBURG TO LACON NORTH.
LATEST CAMS SHOW INCREASING CONVECTION CHANCES INTO CENTRAL IL
LATE EVENING AND OVERNIGHT WHILE SOUTHEAST IL APPEARS TO BE DRY
DURING THAT TIME FRAME. WPC DAY 1 ERO HAS MARGINAL RISK OF
EXCESSIVE RAINFALL OVER NORTHERN/NW CWA THIS AFTERNOON AND
TONIGHT WITH HIGH TROPICAL PWATS OF 1.75-2 INCHES.
OUTFLOW BOUNDARIES FROM CONVECTION GOING INTO TONIGHT TO GET
FURTHER SOUTH INTO OUR CWA ON SATURDAY AND WILL LIKELY SEE MORE
CONVECTION FIRE UP ALONG THESE BOUNDARIES SAT AFTERNOON IN VERY
UNSTABLE TROPICAL AIR MASS, SIMILAR TO TODAYS AIR MASS. SOME
CAMS EVEN SHOW SOME BANDS OF CONVECTION AFFECTING PARTS OF CWA
SAT MORNING, AND MORE CONVECTION DEVELOPING AND MOVING SE SAT
AFTERNOON/EVENING. SPC DAY2 OUTLOOK KEEPS MARGINAL RISK OF
SEVERE STORMS OVER CWA ON SAT FOR DAMAGING WINDS, MAINLY
AFTERNOON INTO MID EVENING. WPC DAY2 ERO HAS MARGINAL CHANCE OF
EXCESSIVE RAINFALL OVER CWA ON SAT INTO SUNDAY. CONVECTION
CHANCES TO CONTINUE ON SUNDAY WITH BEST CHANCES IN SOUTHEAST IL
WHERE WPC DAY3 ERO HAS MARGINAL CHANCE OF EXCESSIVE RAINFALL.
SPC DAY 3 OUTLOOK KEEPS SLIGHT AND MARGINAL RISK OF SEVERE
STORMS SE OF IL AND INDIANA.
NEXT WORK WEEK...
THE COLD FRONT PUSHING SOUTHEAST THROUGH SOUTHERN IL AND INTO NW
KY DURING MONDAY MAY STILL PRODUCE 20-30% CHANCE OF SHOWERS AND
POSSIBLE THUNDERSTORMS OVER SE PART OF CWA, WITH THE 30% POPS IN
SOUTHEAST IL, SE OF A DANVILLE TO SHELBYVILLE LINE. COOLER HIGHS
IN THE LOW TO MID 80S ON MONDAY AND STILL RATHER MUGGY BUT LOWER
DEWPOINTS IN THE UPPER 60S/LOWER 70S. DRY WEATHER IS EXPECTED
MONDAY NIGHT WITH SEASONABLE LOWS IN THE MID TO UPPER 60S. WE
HAVE JUST SLIGHT CHANCE OF CONVECTION ON TUE AFTERNOON IN
SOUTHEAST IL CLOSER TO A FRONTAL BOUNDARY LINGERING IN NW KY AND
SOUTHEAST MO. GEM MODEL APPEARS TOO AGGRESSIVE WITH A WEAK
UPPER LEVEL LOW/TROF AND ITS WIDESPREAD SHOWERS OVER IL ON TUE.
GFS AND ECMWF MODELS SHOW AN UPPER LEVEL RIDGING STARTING TO
PUSH EASTWARD TOWARD THE MS RIVER VALLEY AND INTO IL. SEASONABLE
HIGHS IN THE MID 80S TUE WITH DEWPOINTS 65-70F. DRY WEATHER
AGAIN TUE NIGHT INTO WED MORNING OVER CWA WITH SMALL CHANCES OF
CONVECTION IN SOUTHEAST IL WED AFTERNOON. HIGHS IN THE UPPER 80S
WED WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S. WE HAVE CHANCE
OF SHOWERS/THUNDERSTORMS ACROSS AREA ON THU INTO FRIDAY AS
FRONTAL BOUNDARY LIFTING NE FROM MO AS WARM FRONT ON THU AND
THEN COLD FRONT PUSHING SE INTO CENTRAL OR NW IL ON FRIDAY.
HIGHS IN THE UPPER 80S TO NEAR 90F ON THU AND MID TO UPPER 80S
NEXT FRIDAY AND MUGGY DEWPOINTS 70-75F.
THE CLIMATE PREDICTION CENTER (CPC) 8-14 DAY OUTLOOK FOR JULY
11-17 HAS 35-40% CHANCE OF ABOVE NORMAL TEMPERATURES OVER IL
WITH PRECIPITATION TRENDING NEAR NORMAL.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1209 AM CDT SAT JUL 4 2026
SHOWERS AND THUNDERSTORMS ARE ONGOING ACROSS CENTRAL ILLINOIS
AND ARE EXPECTED TO CONTINUE OVERNIGHT, THOUGH WE SHOULD
GRADUALLY SEE A DIMINISHING TREND IN COVERAGE. STORMS ARE
EXPECTED TO REDEVELOP OVER THE REGION BY SATURDAY AFTERNOON AND
EVENING, THOUGH CONFIDENCE IN SPECIFICS (TIMING/LOCATION) IS
LOW AT THIS TIME. WIND FIELDS WILL BE DISRUPTED BY CONVECTION IN
THE REGION, THUS EXPECT QUITE A BIT OF VARIABILITY IN WIND
DIRECTION, THOUGH WIND SPEED SHOULD GENERALLY STAY UNDER 10 KT
OUTSIDE OF STORMS.
ILX WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ILZ029-031-
036>038-040>057-061>063-066>068-071>073.
KEY MESSAGES...07
UPDATE...25
DISCUSSION...07
AVIATION...DEUBELBEISS
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