129
FXUS63 KILX 190523
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1223 AM CDT SUN JUL 19 2026
KEY MESSAGES
- SCATTERED SEVERE STORMS THIS EVENING: SCATTERED THUNDERSTORMS
WILL MOVE THROUGH CENTRAL ILLINOIS THIS EVENING. THE PRIMARY
THREAT IS LOCALIZED DAMAGING WIND GUSTS FROM COLLAPSING
STORMS, ALONG WITH DOWNPOURS CAPABLE OF PRODUCING 1 TO 2
INCHES OF RAINFALL.
- WILDFIRE SMOKE SUNDAY: SMOKE FROM CANADIAN WILDFIRES WILL FILTER
SOUTHWEST ACROSS THE AREA OVERNIGHT, CREATING HAZY SKIES
THROUGH THE DAY SUNDAY. THOSE SENSITIVE TO POLLUTION SHOULD
TAKE PRECAUTIONS.
- SEVERE WEATHER RISK LATE MONDAY: THERE IS GROWING CONFIDENCE
IN A MORE ORGANIZED SEVERE WEATHER THREAT LATE MONDAY AND
MONDAY NIGHT. SEVERE STORMS CAPABLE OF DAMAGING WINDS AND
LOCALLY HEAVY RAIN ARE EXPECTED TO SWEEP SOUTHEAST INTO THE
REGION.
- DRY AND COOLER LATE WEEK: A STRONG HIGH-PRESSURE SYSTEM
BRINGS A RETURN TO QUIET WEATHER FROM WEDNESDAY THROUGH
FRIDAY. EXPECT DRY CONDITIONS WITH COMFORTABLE, SLIGHTLY
BELOW-NORMAL TEMPERATURES IN THE LOW TO MID-80S.
UPDATE
ISSUED AT 723 PM CDT SAT JUL 18 2026
COLD FRONT HAS ROUGHLY REACHED A MACOMB-HOOPESTON LINE EARLY
THIS EVENING. RADAR CURRENTLY SHOWS A LINE OF CONVECTION
CONTINUING TO ORGANIZE FROM JUST NORTH OF QUINCY TO DECATUR,
WITH ANOTHER CLUSTER OF STORMS NEAR CHAMPAIGN AND DANVILLE.
SEVERE ACTIVITY THUS FAR HAS BEEN MINIMAL, HOWEVER DOWNDRAFT
CAPE'S AROUND 1000 J/KG (PER OUR EVENING BALLOON SOUNDING)
ALONG THE LINE CONTINUE TO POINT TO LOCALIZED STRONG WIND GUSTS.
HEAVY RAINS ARE OCCURRING WITH THE STRONGER STORMS AS WELL, AS
PRECIPITABLE WATERS ARE IN THE 2 INCH VICINITY THIS HOUR. WITH
WEAK SHEAR, THE STORMS OVERALL SHOULD SEE A DIMINISHING TREND AS
WE GET CLOSER TO SUNSET. MOST OF THE FORECAST AREA SHOULD BE DRY
BY MIDNIGHT, THOUGH AREAS SOUTH OF I-70 MAY SEE STORMS LINGER
FOR ANOTHER HOUR OR TWO BEYOND THAT.
REGARDING THE INCOMING SMOKE, 21Z/4PM RUNS OF THE HRRR AND RRFS
CONTINUE TO SUPPORT THE EARLIER THINKING OF SMOKE BEGINNING TO
SPREAD INTO AREAS NORTH OF I-74 AS EARLY AS 3 AM, REACHING A
MACOMB-EFFINGHAM LINE BY AROUND 7 AM. RRFS VISIBILITY PLOTS
SUGGEST 3-5 MILE VISIBILITIES ARE PLAUSIBLE ON SUNDAY. AIR
QUALITY ALERT WAS ISSUED EARLIER PER ILLINOIS EPA GUIDANCE.
DISCUSSION
ISSUED AT 138 PM CDT SAT JUL 18 2026
SHORT TERM FORECAST & CONVECTION TODAY...
A WEST-EAST ORIENTED FRONTAL BOUNDARY CURRENTLY RESIDES NEAR
THE I-80 CORRIDOR IN NORTHERN ILLINOIS AND IS MAKING A SLOW
SOUTHWARD PROGRESSION INTO CENTRAL ILLINOIS. AHEAD OF THIS
FRONT, A WARM AND HUMID AIR MASS REMAINS IN PLACE WITH
TEMPERATURES IN THE UPPER 80S TO LOW 90S AND DEW POINTS IN THE
LOW TO MID 70S. RAP GUIDANCE INDICATES MLCAPE VALUES WILL PEAK
IN THE 2500-3000 J/KG RANGE THIS AFTERNOON, THOUGH DEEP-LAYER
SHEAR REMAINS MODEST AT 20-25 KT. GIVEN THE LACK OF ROBUST
FORCING AND SUB-OPTIMAL SHEAR PROFILES, EXPECT CONVECTIVE
COVERAGE TO REMAIN SCATTERED, WITH SOME STORM CLUSTERING LIKELY.
THE PRIMARY HAZARD WITH THIS ACTIVITY WILL BE DAMAGING WIND
GUSTS FROM COLLAPSING CORES. ADDITIONALLY, WITH MODEST STORM
MOTIONS OF 20-25 MPH TO THE SOUTHEAST, LOCALLY HEAVY RAINFALL IS
POSSIBLE. HREF LPMM GUIDANCE HIGHLIGHTS LOCALIZED SWATHS OF 1-2
INCHES OF RAIN, WHICH THE GROUND SHOULD BE ABLE TO HANDLE GIVEN
CURRENT 3-HOUR FLASH FLOOD GUIDANCE GENERALLY RUNNING BETWEEN 2
AND 3 INCHES. ACTIVITY SHOULD WANE AFTER SUNSET, THOUGH
LINGERING STORMS MAY PERSIST INTO THE OVERNIGHT HOURS ACROSS
PORTIONS OF EAST-CENTRAL AND SOUTHEAST ILLINOIS.
SUNDAY AIR QUALITY...
CANADIAN AND UPPER MIDWEST WILDFIRE ACTIVITY CONTINUES TO
PRODUCE A SIGNIFICANT SMOKE PLUME ACROSS PORTIONS OF THE GREAT
LAKES AND UPPER MIDWEST THIS AFTERNOON. NEAR-SURFACE SMOKE
GUIDANCE FROM THE HRRR SUGGESTS THIS PLUME WILL FILTER SOUTHWEST
ACROSS CENTRAL ILLINOIS BEHIND THE COLD FRONT OVERNIGHT
TONIGHT, LINGERING THROUGH THE DAY SUNDAY. THIS SMOKE, COMBINED
WITH A POST-FRONTAL AIRMASS, WILL LIKELY INHIBIT INSOLATION
SUNDAY, RESULTING IN TEMPERATURES SLIGHTLY BELOW NORMAL, WITH
HIGHS TOPPING OUT IN THE MID-80S. SLOW IMPROVEMENT IS EXPECTED
THROUGH THE DAY MONDAY AS THE FRONT LIFTS BACK NORTH ACROSS THE
REGION WITH SOUTH/SOUTHWEST WINDS OVERSPREADING THE AREA HELPING
TO CLEAR OUT THE SMOKE.
MONDAY SEVERE WEATHER POTENTIAL...
THE FRONT IS EXPECTED TO LIFT BACK NORTH ACROSS THE REGION ON
MONDAY, ALLOWING SOUTH-TO-SOUTHWEST FLOW TO RE-ESTABLISH,
PUSHING TEMPERATURES BACK INTO THE UPPER 80S TO LOWER 90S. WITH
DEW POINTS SURGING INTO THE MID-TO-UPPER 70S, STRONG INSTABILITY
WILL DEVELOP, WITH MLCAPE VALUES PEAKING AROUND 3000 J/KG
MONDAY AFTERNOON AND EVENING. AS A SHORTWAVE TROUGH DIGS ACROSS
THE UPPER MIDWEST, DEEP-LAYER SHEAR IS FORECAST TO INCREASE
SIGNIFICANTLY TO 40-50 KT, CREATING A FAVORABLE PARAMETER SPACE
FOR ORGANIZED SEVERE THUNDERSTORMS. STORMS SHOULD INITIATE OVER
THE UPPER MIDWEST MONDAY AFTERNOON, WITH A STRENGTHENING LOW-
LEVEL JET SUPPORTING MAINTENANCE AND PROPAGATION SOUTHEAST ALONG
THE INSTABILITY GRADIENT INTO CENTRAL ILLINOIS BY LATE EVENING
AND OVERNIGHT. THIS PERIOD WARRANTS CLOSE MONITORING FOR SEVERE
WEATHER POTENTIAL.
EXTENDED PERIOD...
BY TUESDAY, STORMS ARE EXPECTED TO CLEAR THE AREA ALONG A
TRAILING COLD FRONT. THE REMAINDER OF THE WORK WEEK, FROM
WEDNESDAY ONWARD, WILL FEATURE DRY CONDITIONS AND SLIGHTLY
BELOW-NORMAL TEMPERATURES AS A STRONG CANADIAN HIGH SETTLES
ACROSS THE MIDWEST. HIGHS ARE EXPECTED TO REMAIN IN THE LOW TO
MID-80S WITH NO NOTABLE PRECIPITATION CHANCES THROUGH THE LATTER
HALF OF THE WEEK.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1223 AM CDT SAT JUL 19 2026
OVERALL, CONDITIONS SHOULD BE VFR OVERNIGHT AT ALL SITES EXCEPT
CMI THAT WILL STILL BE DEALING WITH MVFR CIGS THROUGH 09Z. AFTER
THAT, THE SMOKE LAYER WILL BE ARRIVING OVERNIGHT AND REMAIN OVER
THE SITES THROUGH THE REMAINDER OF THE FORECAST PERIOD. OBS
UPSTREAM SHOWING VIS DOWN TO AROUND 3SM SO WILL GO WITH THAT TO
START. ALSO INCLUDING A SCATTERED CLOUD LAYER OF JUST ABOVE 3KFT
AT ALL SITES. SMOKE CONTINUES INTO THE EVENING BUT CLOUD LAYER
MAY BECOME MORE THIN HIGH CIRRUS. WINDS WILL BE LESS THAN 10KTS
AND OUT OF THE EAST DURING THE DAY, WITH LIGHT AND VARIABLE
OVERNIGHT AND TOMORROW EVENING.
ILX WATCHES/WARNINGS/ADVISORIES
AIR QUALITY ALERT UNTIL MIDNIGHT CDT SUNDAY NIGHT FOR
ILZ027>031-036>038-040>057-061>063-066>068-071>073.
KEY MESSAGES...DEUBELBEISS/GEELHART
UPDATE...GEELHART
DISCUSSION...DEUBELBEISS
AVIATION...AUTEN
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