691
FXUS63 KILX 051952
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
252 PM CDT SUN JUL 5 2026
KEY MESSAGES
- A FEW BRIEF AFTERNOON THUNDERSTORMS ARE POSSIBLE (30-40%
CHANCE) ACROSS CENTRAL ILLINOIS THIS AFTERNOON AND EARLY
EVENING. SEVERE WEATHER IS NOT EXPECTED, AND STORM ACTIVITY
WILL FADE QUICKLY AFTER SUNSET.
- DRY AND SEASONABLY WARM CONDITIONS RETURN MONDAY THROUGH
WEDNESDAY, WITH AFTERNOON TEMPERATURES PEAKING IN THE LOW TO
MID 80S MONDAY AND MID TO UPPER 80S TUE/WED.
DISCUSSION
ISSUED AT 245 PM CDT SUN JUL 5 2026
ISOLATED DIURNAL CONVECTION FADING THIS EVENING
LATEST RADAR MOSAIC SHOWS ISOLATED CONVECTION BEGINNING TO
DEVELOP ALONG HIGHWAY 50 IN SOUTHEAST IL AND MORE SCATTERED
CONVECTION OVER EASTERN MO INTO FAR WESTERN/SW IL OVER MS RIVER
VALLEY. MORE UNSTABLE AIRMASS IN PLACE OVER SOUTHERN AND SW IL
WHERE CONVECTION DEVELOPING WITH MLCAPES APPROACHING 2000 K/KG.
EFFECTIVE BULK SHEAR IS WEAK, AT 20 KTS OR LESS OVER IL. PWATS
STILL QUITE HIGH FROM 1.6-1.85 INCHES, HIGHEST IN SOUTHEAST IL.
THE 19Z/2 PM SURFACE ANALYSIS SHOWS WEAK 1012 MB LOW PRESSURE
OVER NW OHIO WITH ITS WEAK COLD FRONT PUSHING THROUGH SE IN AND
SOUTHERN IL (PASSING SE OF CWA). NOT AS HOT AND HUMID OVER
CENTRAL/SE IL AS THIS PAST WEEK WITH TEMPS IN THE LOWER 80S
(INSTEAD OF UPPER 80S/LOWER 90S) BUT STILL RATHER MUGGY
DEWPOINTS IN THE UPPER 60S AND LOWER 70S. LATEST CAMS SHOW
ISOLATED DIURNALLY DRIVEN CONVECTION OVER AREAS MAINLY SOUTH
OF PEORIA DISSIPATE AT DUSK. SPC DAY1 OUTLOOK KEEPS MARGINAL
RISK OF SEVERE STORMS SE OF IL/IN WHILE WPC DAY1 ERO HAS
MARGINAL RISK OF EXCESSIVE RAINFALL OVER THE WABASH RIVER VALLEY
IN SOUTHEAST IL WHERE HIGHER PWATS ARE OVER 1.8 INCHES. THE
LATEST HRRR RUNS ALSO SHOW SOME LOW CLOUDS/STRATUS DEVELOPING
AND MOVING SW INTO CENTRAL IL (SE OF IL RIVER) OVERNIGHT INTO
MID MON MORNING BUT LIMITED FOG FORMATION. SEASONABLE LOWS
OVERNIGHT IN THE MID TO UPPER 60S, MILDEST IN SOUTHEAST IL.
MONDAY THROUGH WEDNESDAY: MOSTLY DRY AND SEASONABLY WARM
WEAK UPPER LEVEL TROF INTO THE SOUTHERN GREAT LAKES AND
EXTENDING SW TO A WEAK UPPER LEVEL LOW OVER THE OZARKS ON
MONDAY. MEANWHILE A WEAK 1018-1020 MB SURFACE HIGH PRESSURE
SETTLES INTO THE GREAT LAKES AND INTO IL MON/TUE AND PROVIDE
QUIETER WEATHER TO CENTRAL IL. ISOLATED SHOWERS/THUNDERSTORMS
POSSIBLE IN SOUTHEAST IL MONDAY AFTERNOON AND TUE AFTERNOON
CLOSER TO FRONTAL BOUNDARY OVER KY/TN AND A BIT MORE INSTABILITY
LINGERING IN SOUTHEAST IL TO SUPPORT DIURNALLY DRIVEN ISOLATED
CONVECTION. HIGHS IN THE LOW TO MID 80S MONDAY AND MID 80S TUE.
STILL RATHER MUGGY WITH DEWPOINTS IN THE UPPER 60S TO AROUND 70F
MON/TUE. STRONG MID/UPPER LEVEL RIDGE STARTS NOSING INTO THE
UPPER MIDWEST TUE/WED FROM THE DESERT SOUTHWEST AS 500 MB
HEIGHTS RISE TO 588-590 DECAMETERS OVER IL. THIS WILL TEND TO
BRING IN WARMER TEMPERATURES ALONG WITH PROVIDING SOME CAPPING
TO LIMIT CONVECTION. THOUGH STILL HAVE SLIGHT CHANCE OF
CONVECTION SE OF I-70 ON WED AFTERNOON AGAIN. HIGHS WED IN THE
MID TO UPPER 80S AND HEAT INDICES IN THE LOWER 90S WED
AFTERNOON.
THURSDAY AND FRIDAY: UNSETTLED WEATHER RETURNS
A STRONGER NORTHERN STREAM SHORT WAVE TRACKING ESE OVER THE
UPPER MIDWEST/UPPER MS RIVER VALLEY WED NIGHT AND INTO THE
SOUTHERN GREAT LAKES REGION THU, TO BRING A FRONTAL BOUNDARY
INTO NORTHERN IL THU AND BRING INCREASING CHANCES OF CONVECTION
TO CENTRAL IL OVERNIGHT WED NIGHT AND THU. THIS BOUNDARY PUSHES
SOUTH INTO CENTRAL IL THU NIGHT AND FRIDAY AND INTO SOUTHERN IL
FRI NIGHT AND SATURDAY. WILL SEE HIGHER CHANCES OF CONVECTION
THU/FRI AND SHIFTING MORE SOUTH ON SATURDAY. PW VALUES ARE
RISING BACK UP TO 2 INCHES LATE WORK WEEK AND SUPPORTS HEAVY
RAIN CHANCES. WILL SEE MORE UNSTABLE AIRMASS RETURN TO AREA
THU/FRI. CSU-MLP AND CIPS SHOWS MARGINAL RISK OF SEVERE STORMS
NW IL WED NIGHT AND OVER MORE OF CWA THU/THU NIGHT AND SHIFTING
INTO SOUTHERN/SE IL FRIDAY INTO SATURDAY.
THE CLIMATE PREDICTION CENTER (CPC) 8-14 DAY OUTLOOK FOR JULY
13-19TH HAS 45-55% CHANCE OF ABOVE NORMAL TEMPERATURES OVER IL
(HIGHEST IN WEST CENTRAL IL) AND 33-40% CHANCE OF BELOW NORMAL
PRECIPITATION. THE ECMWF AND GEM MODELS ARE BOTH SHOWING A
STRONG 500 MB HIGH/RIDGE (598-600 DECAMETERS) BUILDING EASTWARD
INTO THE MIDWEST JULY 13-15TH WHILE GFS IS KEEPING THE STRONG
RIDGE FURTHER WEST OVER THE ROCKIES DURING THIS TIME FRAME. IF
ECWMF AND GEM MODELS VERIFY, AN EXTENDED HEAT WAVE MAY RETURN TO
THE MIDWEST INCLUDING IL FOR MIDDLE TO LATER PART OF NEXT WEEK.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1255 PM CDT SUN JUL 5 2026
BROKEN CUMULUS CLOUDS WITH MVFR CEILINGS POSSIBLE EARLY THIS
AFTERNOON TO LIFT TO VFR DURING MID/LATE AFTERNOON. ISOLATED
SHOWERS AND THUNDERSTORMS POSSIBLE IN EASTERN IL FROM 20-24Z AND
CARRIED VCSH AT BMI, DEC AND CMI WITH PROB30 GROUP AT CMI.
LATEST HRRR RUN IS SHOWING PATCHES OF LOW CLOUDS WITH MVFR BASES
MOVING BACK INTO PARTS OF CENTRAL AND EASTERN IL DURING
OVERNIGHT INTO MID MON MORNING, THOUGH NOT AS EXTENSIVE AS LAST
NIGHT AND THIS PAST MORNING. NNW WINDS 5-10 KTS VEER NNE TONIGHT
INTO MONDAY.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...07
DISCUSSION...07
AVIATION...07
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