244
FXUS63 KILX 220511
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1211 AM CDT SAT AUG 22 2026
KEY MESSAGES
- A SLIGHT RISK OF SEVERE THUNDERSTORMS EXISTS THIS EVENING
ALONG AND NORTH OF A LINE FROM BEARDSTOWN TO LINCOLN TO GIBSON
CITY. HAIL (15%), WIND (15%), AND TORNADO (2%) THREATS WILL
EXIST IN THIS AREA, WITH LOWER PROBABILITIES FURTHER SOUTH TO
NEAR I-70.
DISCUSSION
ISSUED AT 215 AM CDT FRI AUG 21 2026
WEAK HIGH PRESSURE RIDGE ~1018 MB WAS OVER NEAR CENTRAL IL EARLY
THIS AFTERNOON AND PROVIDING A DELIGHTFUL LATE SUMMER DAY WITH
MOSTLY SUNNY SKIES. TEMPERATURES WERE IN THE LOWER 80S AT 2 PM
WHILE DEWPOINTS WERE IN THE MID TO UPPER 60S EXCEPT LOWER 70S
FROM GALESBURG AND MACOMB WEST/NW. A WEAK COLD FRONT WAS OVER
CENTRAL WI INTO SOUTHEAST IOWA. RADAR MOSAIC SHOWS SCATTERED
CONVECTION OVER NORTHERN IL FROM I-88 NORTH INTO SOUTHERN WI AND
TRACKING ESE. MODERATELY UNSTABLE AIRMASS IN PLACE OVER THE IL
RIVER VALLEY WHERE MLCAPES 1500-2500 J/KG NW OF I-55 WHILE BULK
SHEAR VALUES OF 30-35 KTS OVER IL RIVER VALLEY AND OVER 40 KTS
WEST OF IL OVER CENTRAL AND NORTHERN MO. SPC JUST ISSUED A
MESOSCALE DISCUSSION OVER NORTHERN HALF OF IL NORTH OF LINCOLN
WHERE SEVERE STORM THREAT IS INCREASING AND MONITORING A POSSIBLE
WATCH BOX. HRRR AND RRFS MODELS SHOW BROKEN BAND OF CONVECTION
MOVING INTO FAR NORTHERN CWA JUST AFTER SUNSET AND TOWARD I-55
BY LATE EVENING, AND WEAKENING AS IT MOVES TOWARD I-70 AROUND 3
AM. SPC CONTINUES SLIGHT RISK OF SEVERE STORMS THIS EVENING
ALONG AND NORTH OF A LINE FROM BEARDSTOWN TO LINCOLN TO GIBSON
CITY. HAIL (15%), WIND (15%), AND TORNADO (2%) THREATS WILL
EXIST IN THE SLIGHT RISK AREA. CAPES REACH 2000-3000 J/KG OVER
THE IL RIVER VALLEY NW OF I-55 WHILE WIND SHEAR VALUES 30-40 KTS
AND ALSO IN FAVORABLE REGION OF SE MOVING UPPER LEVEL JET FOR
ENHANCED LIFT. FURTHER SOUTH A MARGINAL RISK EXISTS AS FAR
SOUTHEAST AS NEAR I-70, WITH MAINLY LOW END HAIL/WIND (5%)
THREATS FOR THIS EVENING IN THIS AREA. WPC DAY1 OUTLOOK HAS
MARGINAL RISK OF EXCESSIVE RAINFALL OVER NORTHERN CWA THIS
EVENING WHERE POCKETS OF 1 INCH OR MORE OF RAIN POSSIBLE ON A
SATURATED GROUND. BUT CONVECTION BANDS WILL BE MORE PROGRESSIVE
THAN WED NIGHT SYSTEM SO RAINFALL AMOUNTS SHOULD BE MUCH LOWER.
QUIETER WEATHER IS GENERALLY EXPECTED THIS WEEKEND INTO EARLY
NEXT WEEK OVER CENTRAL/SE IL, THOUGH A FEW MODEL MEMBERS SHOW
ISOLATED CONVECTION (20% OR LESS) OVER NE CWA SAT AFTERNOON
WHERE MUCAPES GET TO 1000-1500 J/KG. THE STRONGER SHORT WAVE
FORCING IS NE OF CWA SAT AFTERNOON OVER NE IL INTO NORTHERN IN
WHERE BETTER CHANCE OF CONVECTION WILL BE. A NORTHWEST UPPER
LEVEL FLOW TO PREVAIL OVER IL THROUGH MIDDLE OF NEXT WEEK WITH
STRONG MID/UPPER LEVEL RIDGE OVER SOUTHWEST STATES AND UPPER
LEVEL LOW/TROF IN EASTERN CANADA AND NORTHEAST US. ANOTHER
NORTHERN STREAM SHORT WAVE DISTURBANCE TO MOVE SE INTO THE
MIDWEST FOR MIDDLE OF NEXT WEEK AND BRING NEXT CHANCE OF
CONVECTION AROUND WEDNESDAY THOUGH CURRENT NBM JUST HAS SLIGHT
POPS OVER AREA. TEMPS TO BE NEAR A BIT BELOW NORMAL EARLY NEXT
WEEK WITH HIGHS IN THE UPPER 70S TO LOWER 80S SUN/MONDAY AND
COOLEST NIGHT SUNDAY NIGHT WITH LOWS IN MID TO UPPER 50S. TEMPS
MODERATE A BIT FOR MIDDLE OF NEXT WEEK ALONG WITH INCREASING
HUMIDITY LEVELS/DEWPOINTS WITH HIGHS BACK IN THE LOW TO MID 80S
TUE-FRI (MID TO UPPER 80S SOUTHERN CWA WED-FRI).
THE CLIMATE PREDICTION CENTER (CPC) 8-14 DAY OUTLOOK FOR AUG
29-SEP 4 HAS 40-50% CHANCE OF ABOVE NORMAL TEMPERATURES OVER
CENTRAL/SE IL AND PRECIPITATION TRENDING NEAR NORMAL EXCEPT
SLIGHT ABOVE NORMAL NEAR THE INDIANA BORDER.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1210 AM CDT SAT AUG 22 2026
A LINE OF THUNDERSTORMS WILL CONTINUE SOUTHEAST ACROSS CENTRAL
ILLINOIS DURING THE EARLY OVERNIGHT HOURS, BUT SHOULD BE CLEAR
OF THE I-72 TERMINALS BY AROUND 07Z. BEHIND THE STORMS, WINDS
WILL GRADUALLY SET UP OUT OF THE NORTHWEST THE REMAINDER OF THE
PERIOD, PICKING UP INTO THE 10-12KT RANGE DURING THE DAY
SATURDAY.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...07
DISCUSSION...07
AVIATION...DEUBELBEISS
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