170
FXUS63 KILX 231042
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
542 AM CDT WED SEP 23 2026
KEY MESSAGES
- NO SIGNIFICANT WEATHER IS EXPECTED ACROSS CENTRAL ILLINOIS
OVER THE NEXT WEEK.
DISCUSSION
ISSUED AT 239 AM CDT WED SEP 23 2026
07Z/2AM SURFACE ANALYSIS SHOWS A SPRAWLING RIDGE OF HIGH
PRESSURE EXTENDING FROM QUEBEC SOUTHWESTWARD INTO THE
MID-MISSISSIPPI RIVER VALLEY. DESPITE SYNOPTIC SUBSIDENCE
BENEATH THE RIDGE AND DRY NORTHEASTERLY FLOW FROM THE GREAT
LAKES, AMPLE BOUNDARY LAYER MOISTURE REMAINS TRAPPED BENEATH AN
INVERSION. WHILE SKIES PARTIALLY CLEARED YESTERDAY AFTERNOON,
THE LOW OVERCAST HAS RETURNED EVERYWHERE ALONG/EAST OF A PEORIA
TO SPRINGFIELD LINE EARLY THIS MORNING. WHILE THE WESTWARD
ADVANCE OF THE CLOUD SHIELD HAS SLOWED SOMEWHAT OVER THE PAST
HOUR OR TWO, THINK OVERCAST CONDITIONS WILL EXIST ACROSS THE
ENTIRE KILX CWA BY SUNRISE. FORECAST SOUNDINGS STRONGLY SUGGEST
THE LOW-LEVEL MOISTURE WILL REMAIN LOCKED IN PLACE TODAY:
HOWEVER, THE RRFS SKY FORECAST ONCE AGAIN OFFERS HOPE FOR SOME
PARTIAL SUNSHINE THIS AFTERNOON...PARTICULARLY ALONG/WEST OF THE
I-55 CORRIDOR. GIVEN CLOUD COVER AND A COOL NE BREEZE, HIGH
TEMPERATURES WILL REMAIN BELOW NORMAL FOR THIS TIME OF YEAR IN
THE UPPER 60S TO AROUND 70 DEGREES. ANY PARTIAL CLEARING THAT
OCCURS WILL VANISH BY TONIGHT AS LOW CLOUDS ONCE AGAIN SPREAD
AND/OR DEVELOP WESTWARD ACROSS THE AREA AFTER DARK.
THE UPPER AIR PATTERN CURRENTLY FEATURES A WEAK REX BLOCK WITH
A HIGH OVER SOUTHERN CANADA AND A LOW ACROSS CENTRAL ILLINOIS
INTO THE OHIO RIVER VALLEY. MODELS CONTINUE TO SHOW THE BLOCK
GRADUALLY SHIFTING EASTWARD AND BREAKING DOWN AS THE LOW DEEPENS
OVER THE MID-ATLANTIC REGION. WITH AN INCREASINGLY STRONG UPPER
LOW TO THE EAST ESSENTIALLY BLOCKING THE PROGRESS OF ANY SYSTEMS
ACROSS THE CENTRAL/EASTERN CONUS, A NARROW UPPER RIDGE WILL FORM
OVER THE MIDWEST AND REMAIN IN PLACE THROUGH EARLY NEXT WEEK.
DESPITE THE PRESENCE OF THE RIDGE, CLOUD COVER WILL BE SLOW TO
CLEAR FROM CENTRAL ILLINOIS AS BOUNDARY LAYER FLOW REMAINS E/NE
INTO THE WEEKEND. AM THEREFORE EXPECTING MOSTLY CLOUDY SKIES
AGAIN ON THURSDAY BEFORE PARTIAL SUNSHINE FINALLY RETURNS BY
FRIDAY.
A SHORT-WAVE TROUGH CROSSING THE ROCKIES INTO THE PLAINS WILL
RUN INTO THE BLOCKING PATTERN AND COME TO A HALT OVER THE
WEEKEND. THIS SYSTEM WILL COME CLOSE ENOUGH TO CAUSE AN
INCREASE IN CLOUD COVER AND PERHAPS SOME LIGHT SHOWERS WEST OF
THE I-55 CORRIDOR SATURDAY/SUNDAY. ALL MODELS EVENTUALLY WEAKEN
THE WAVE AS THE NARROW RIDGE AXIS HOLDS FIRM. AS A RESULT, ANY
RAIN CHANCES ACROSS THE WESTERN KILX CWA WILL COME TO AN END BY
SUNDAY AFTERNOON/MONDAY AS TEMPERATURES CLIMB BACK TO SEASONAL
NORMALS IN THE MIDDLE TO UPPER 70S. AFTER THAT, THE MID-ATLANTIC
UPPER LOW IS PROGGED TO WEAKEN AND EJECT NORTHEASTWARD AS A
PROMINENT TROUGH SWINGS ACROSS THE PLAINS BY EARLY NEXT WEEK. AS
THIS WAVE AND ITS ASSOCIATED COLD FRONT APPROACH, BOUNDARY
LAYER FLOW WILL BECOME S/SW AND TEMPS WILL SOAR INTO THE 80S BY
NEXT TUESDAY. THE NEXT SIGNIFICANT CHANCE FOR PRECIPITATION
WILL ARRIVE WITH THE FRONT, WHICH IS CURRENTLY PROJECTED TO PUSH
INTO CENTRAL ILLINOIS TUESDAY NIGHT INTO WEDNESDAY.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 542 AM CDT WED SEP 23 2026
10Z/5AM SATELLITE IMAGERY/LOCAL OBS REVEAL MVFR CEILINGS
ALONG/SOUTH OF A KAAA TO KCMI LINE. FURTHER NORTH, DRIER
BOUNDARY LAYER ADVECTING INTO THE AREA FROM THE GREAT LAKES HAS
RESULTED IN VFR CEILINGS AT BOTH KPIA AND KBMI EARLY THIS
MORNING. BASED ON SATELLITE TRENDS AND THE LATEST
HRRR/CONSSHORT, IT APPEARS THE LOW OVERCAST WILL SCATTER AND/OR
LIFT TO VFR AT KSPI BY AROUND 16Z...BUT SHOULD REMAIN MVFR
FURTHER EAST AT KDEC/KCMI THROUGH THE REMAINDER OF THE 12Z TAF
PERIOD. MODELS ARE CONSISTENTLY SHOWING THE LOW CLOUDS
RE-DEVELOPING AND SPREADING BACK WESTWARD LATER TODAY INTO
TONIGHT, RESULTING IN A RETURN TO MVFR AT KBMI BY 17Z, AT KPIA
BY 23Z, AND AT KSPI BY 00Z. WINDS WILL BE NE AT 10-15KT.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...BARNES
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