164
FXUS63 KILX 060542
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1242 AM CDT THU AUG 6 2026
KEY MESSAGES
- LOCALIZED SEVERE AND FLOODING RISK TODAY: A STRONG STORM OR
TWO WITH PRIMARILY DAMAGING WIND GUSTS CANNOT BE RULED OUT,
MAINLY W OF A CHAMPAIGN TO TAYLORVILLE LINE. WIDESPREAD
SHOWERS AND TSTORMS TONIGHT MAY RESULT IN LOCALIZED FLOODING
IN THE SW.
- OCCASIONAL SHOWERS & STORMS THROUGH FRIDAY: A SLOW-MOVING COLD
FRONT WILL SUPPORT ON-AND-OFF RAIN CHANCES (20-50% FROM THE
NBM) THURSDAY AND FRIDAY, ESPECIALLY INTO EASTERN ILLINOIS.
- HEAT/HUMIDITY AND MCS CHANCES LATE WEEKEND: FAVORABLE PATTERN
FOR INCREASED HEAT/HUMIDITY (HEAT INDICES NEAR 100F) AND
THUNDERSTORM COMPLEXES LATE THIS WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 239 PM CDT WED AUG 5 2026
SYNOPSIS
MIDDAY RADAR MOSAIC DEPICTS A DECAYING AREA OF RAIN SHOWERS W
OF I-55 (NOW DISSIPATED) THAT BELONGED TO THE STRATIFORM
PRECIPITATION REGION OF A MESOSCALE CONVECTIVE COMPLEX FROM
EARLIER THIS AM ACROSS NORTHERN MO/SOUTHERN IA. SINCE THEN,
RENEWED DEVELOPMENT OF SHOWERS AND THUNDERSTORMS HAS BEEN
ONGOING IN SOUTHEASTERN IA, NOW BEGINNING TO PUSH TOWARDS OUR
WESTERN COUNTIES. WITH THIS ACTIVITY, GOES-16 SHOWS A MIX OF
DECAYING ANVIL DEBRIS AND MID-LEVEL STRATUS TRANSITIONING TO
MAINLY CLEAR SKIES (AND SOME DIURNAL CUMULUS) SE OF I-55.
CONSEQUENTLY, THIS IS WHERE AFTERNOON TEMPERATURES WILL REACH
THE HIGHEST (MID 80S) WHILE AREAS NORTH AND WEST REMAIN A BIT
COOLER. SURFACE ANALYSIS OUTLINES A SLOW-MOVING COLD FRONT
DRAPED SW FROM LAKE MICHIGAN TO SOUTHERN KS. THIS FRONT WILL
GRADUALLY ENTER OUR WESTERN CWA TODAY AND SERVE AS THE PRIMARY
FORCING MECHANISM FOR PRECIPITATION TODAY, THOUGH THE RIGHT
ENTRANCE REGION OF AN UPPER JET IS LOCATED NEARBY AS WELL.
LOCALIZED SEVERE AND FLOODING RISK TODAY
THERE APPEARS TO BE TWO MAIN WAVES OF SHOWERS AND THUNDERSTORMS
TODAY. THE FIRST WILL BE ASSOCIATED WITH THE AFOREMENTIONED
ACTIVITY MOVING EASTWARD OUT OF IA. THIS ROUND SHOULD LAST UNTIL
AROUND SUNSET, MAINLY W OF I-55. THEREAFTER, A FEW DRY HOURS ARE
LIKELY ACROSS MUCH OF THE AREA. THE NEXT WAVE OF RAINFALL SHOULD
BEGIN TO MATERIALIZE (MAINLY SW OF A HAVANA TO SHELBYVILLE LINE)
AFTER 03Z/10PM. EVEN THOUGH CLOUD DEBRIS IS LIMITING
INSTABILITY, A FEW POCKETS OF 500-1000 J/KG OF MLCAPE MAY
DEVELOP ALONGSIDE THE 35-45 KTS OF BULK SHEAR THAT IS EXPECTED
TO SETTLE IN THIS AFTERNOON. THUS, SPC HAS A LEVEL 1 OF 5 SEVERE
RISK W OF A CHAMPAIGN TO TAYLORVILLE LINE TODAY. THERE IS A ALSO
A LOW, BUT NON-ZERO CHANCE FOR A TORNADO OR TWO, GIVEN 0-1 KM
SHEAR AROUND 15 KTS AND 0-1 KM SRH IN THE 100-150 M2S2 RANGE. AS
FOR FLOODING, WPC HAS A LEVEL 2 OF 4 RISK FOR EXCESSIVE RAINFALL
ACROSS MUCH OF THE AREA, GIVEN PWATS OF 1.7-1.9 INCHES AND
TRAINING STORM BEHAVIOR. THE BEST CHANCE FOR FLOODING IS IN OUR
FAR SW CWA TONIGHT, CLOSER TO THE NOSE OF THE LLJ. HREF LPMM
DOES SHOW SOME POCKETS OF 2-3 INCHES, THOUGH MANY AREAS SHOULD
SEE AROUND ONE INCH OR LESS.
OCCASIONAL SHOWERS & STORMS THROUGH FRIDAY
THE AFOREMENTIONED COLD FRONT WILL CONTINUE TO SLOWLY DRAG
EASTWARD THROUGH CENTRAL IL INTO FRIDAY, PROMOTING DAILY SHOWER
AND STORM CHANCES (ALBEIT MORE ISOLATED/SCATTERED THAN TODAY).
WITH THE HIGH MOISTURE CONTENT REMAINING IN PLACE AND SLOW
MOVEMENT OF CONVECTIVE CELLS, WPC COVERS THE AREA WITH A
MARGINAL RISK IN THE ERO ON THURSDAY, AND THEN SE OF I-72 ON
FRIDAY. NO ORGANIZED STRONG OR SEVERE STORMS ARE ANTICIPATED AT
THIS TIME.
LATE ON FRIDAY, ANOTHER COLD FRONT WILL BE MOVING INTO THE
MIDWEST, WHICH MAY YIELD SOME THUNDERSTORMS ACROSS IA. THERE IS
A LOW CHANCE THAT THIS ACTIVITY COULD PERSIST AND DIVE INTO
WESTERN IL OVERNIGHT, AS UP TO 2000 J/KG OF MUCAPE IS EXPECTED
ACROSS THE AREA.
HEAT/HUMIDITY AND MCS CHANCES LATE WEEKEND
MOST GUIDANCE (WITH THE EXCEPTION OF THE GFS) SUGGESTS THE
EARLY WEEKEND COLD FRONT WILL FULLY SWEEP THROUGH CENTRAL IL,
LEAVING SATURDAY MAINLY DRY WITH LIGHTER WINDS AND SLIGHTLY
LOWER HUMIDITY. THAT SHOULD CHANGE QUICKLY BY SUNDAY, HOWEVER,
AS SOUTHERLY FLOW AND INCREASED HEAT & HUMIDITY RETURN. SUNDAY
AND MONDAY WILL BE THE WARMEST, WITH HIGHS REACHING INTO THE
LOW 90S ACROSS THE SOUTH/WEST PORTION OF OUR CWA AND AREAWIDE
DEW POINTS IN THE MID 70S. HERE, HEAT INDICES COULD TOP 100
DEGREES BOTH AFTERNOONS. THE LREF INDICATES 20-40% PROBABILITIES
OF EXCEEDING 100F, MAINLY S OF A BEARDSTOWN TO EFFINGHAM LINE.
THE ONLY EXCEPTION TO THIS HEAT RISK WOULD BE IF ANY
THUNDERSTORM CLUSTER PASSES THROUGH TO DISRUPT PEAK DIURNAL
HEATING.
THE SYNOPTIC PATTERN, FEATURING A 45-60 KT BELT OF W/NW FLOW
ACROSS THE UPPER MIDWEST, WILL DOMINATE INTO MUCH OF NEXT WEEK.
OCCASIONAL SHORTWAVES ARE EXPECTED TO TRAVERSE ATOP THE RIDGE
AND INTO THE AREA IN THIS GENERAL TIMEFRAME, BUT NAILING DOWN
THE EXACT TIMING IS IMPOSSIBLE AT THIS RANGE. WITH DAILY MUCAPE
OF 2500-4000 J/KG AND 25-35 KT OF 0-6 KM SHEAR, STORM COMPLEXES
FROM THESE DISTURBANCES MAY MATERIALIZE IN THE REGION. ONE OR
TWO COULD DIVE INTO CENTRAL IL AND POSE A DAMAGING WIND THREAT.
THOUGH SPC HAS NO OFFICIAL OUTLINES FOR SEVERE WEATHER AT THIS
TIME, CSU-MLP GUIDANCE DOES HIGHLIGHT DAILY CHANCES FOR STRONG-
SEVERE STORMS, HIGHEST ON SUNDAY AND MONDAY (15%+).
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1242 AM CDT THU AUG 6 2026
ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE FOR MUCH OF THE
UPCOMING 24 HOURS AS A FRONTAL ZONE REMAINS STALLED OVER THE
AREA. IN THE NEXT FEW HOURS, ANY THUNDERSTORM ACTIVITY SHOULD BE
TOO ISOLATED FOR MENTION IN TAFS, HOWEVER SCATTERED SHOWERS
COULD BRING BRIEF MVFR CONDITIONS. AN AREA OF THUNDERSTORMS
OVER MO SHOULD MIGRATE EASTWARD OVERNIGHT, MOST LIKELY TO AFFECT
KSPI AND KDEC FROM AROUND 8-12Z. AFTER 16Z-18Z, PROBABILITIES
FOR SHOWERS AND THUNDERSTORMS BECOME TOO LOW FOR MENTION IN TAFS
WHILE MVFR CIGS GRADUALLY IMPROVE TO VFR UNTIL ANOTHER
DISTURBANCE IN THE EVENING BRINGS CHANCES FOR THUNDERSTORMS
WORTHY OF A PROB30 MENTION ALONG THE I-72 TERMINALS KSPI-KDEC-
KCMI. WINDS GENERALLY E 3-6 KTS OVERNIGHT THEN BECOMING S-SW 4-7
KTS BY 15Z.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...DEUBELBEISS
DISCUSSION...DEUBELBEISS
AVIATION...37
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