931
FXUS63 KILX 231930
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
230 PM CDT SUN AUG 23 2026
KEY MESSAGES
- SEASONAL AND MOSTLY DRY WEATHER IS EXPECTED THROUGH AT LEAST
TUESDAY EVENING OVER CENTRAL AND SOUTHEAST IL.
- THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS ARRIVES ON
WEDNESDAY AFTERNOON AND WEDNESDAY EVENING. SOME OF THESE
THUNDERSTORMS COULD BE STRONG TO MARGINALLY SEVERE.
DISCUSSION
ISSUED AT 230 PM CDT SUN AUG 23 2026
NICE LATE SUMMER WEATHER PATTERN EXPECTED THROUGH TUESDAY ACROSS
CENTRAL AND SOUTHEAST IL AFTER A VERY ACTIVE WEATHER PATTERN 1ST
3 WEEKS OF THE MONTH. WEAK 1021 MB SURFACE HIGH PRESSURE OVER NW
MO INTO CENTRAL IOWA AND UPPER MS RIVER VALLEY TO SETTLE OVER IL
DURING TONIGHT AND INTO THE MID OHIO RIVER VALLEY ON MON AND MON
NIGHT WHILE RIDGING BACK INTO CENTRAL/NE IL. THIS WILL CONTINUE
FAIR WX ACROSS THE PRAIRIE STATE INTO TUESDAY WITH DRY CONDITIONS
AND MORE COMFORTABLE HUMIDITY LEVELS. NW WINDS 5-15 MPH AND
SCATTERED DIURNALLY DRIVEN CUMULUS CLOUDS OVER CENTRAL AND NE
IL TO DISSIPATE AFTER SUNSET WHILE VEIL OF HIGH CLOUDS OVER MO
AND CENTRAL/SE IOWA IS CLIPPING WEST CENTRAL AND SW IL. A
DISTURBANCE OVER THE CENTRAL PLAINS TO KEEP CHANCES OF
CONVECTION WELL SW OF IL OVER CENTRAL AND SW MO TONIGHT INTO
EARLY MONDAY AS IT TRACKS SE ACROSS THE MO VALLEY/OZARKS. PATCHY
SHALLOW GROUND FOG MAY DEVELOP DURING OVERNIGHT INTO EARLY MON
MORNING MAINLY NEAR RIVER VALLEYS AND LOW LYING RURAL ARES. HREF
ONLY HAS 15-30% CHANCE OF VSBYS GETTING TO 5 MILES OR LESS OVER
PORTIONS OF CWA LATER TONIGHT. HRRR AND RAP SHOW VERY LITTLE
FOG FORMATION WITH DRIER AIR IN PLACE WHILE NAM AND GFSLAMP SHOW
SOME PATCHY FOG DEVELOPMENT MAINLY NEAR RIVER VALLEYS.
COMFORTABLE NIGHT AHEAD WITH LOWS IN THE MID TO UPPER 50S. HIGHS
MONDAY AROUND 80F WITH LOWER 80S SOUTHEAST IL AND SW CWA, WITH
SCATTERED CUMULUS CLOUDS DEVELOPING BY MIDDAY GIVING PARTLY TO
MOSTLY SUNNY SKIES. LOWS 55-60F MONDAY NIGHT AND HIGHS IN THE
LOW TO MID 80S TUESDAY. WINDS TO STAY FAIRLY LIGHT GENERALLY
UNDER 10 MPH TONIGHT THROUGH TUE.
A NORTHERN STREAM UPPER LEVEL SHORTWAVE MOVING OVER THE SOUTHERN
CANADIAN PRAIRIE PROVINCES NEXT FEW DAYS, WILL TRACK SE THROUGH
THE NORTHERN GREAT LAKES REGION, SENDING A COLD FRONT SE THROUGH
IL DURING WED AFTERNOON AND WED NIGHT. THIS WILL LIKELY BRING
OUR NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS. INCREASING SOUTH
TO SW FLOW AHEAD OF THE COLD FRONT TO BRING IN WARMER AND MORE
HUMID AIR INTO CENTRAL/SE IL ON WED. HIGHS IN THE MID TO UPPER
80S WED AND POSSIBLY APPROACHING 90F FROM SPRINGFIELD SW WITH
DEWPOINTS CLIMBING INTO THE UPPER 60S/LOWER 70S. A CAP
INITIALLY IN PLACE ON WED COULD BREAK LATER IN THE AFTERNOON AND
WED EVENING ALLOWING THUNDERSTORMS TO DEVELOP IN A MODERATE
INSTABILITY WITH WIND SHEAR ENVIRONMENT. ALTHOUGH THE BETTER
UPPER FORCING WILL BE DISPLACED TO OUR NORTH, A FEW STRONG TO
MARGINALLY SEVERE STORMS COULD DEVELOP LATER WEDNESDAY
AFTERNOON AND EVENING, POSING A THREAT FOR DAMAGING WIND GUSTS.
COULD SEE LINGERING LOW CHANCES OF SHOWERS/THUNDERSTORMS IN SE
IL EARLY THU, OTHERWISE FAIR WEATHER WITH SEASONABLE
TEMPERATURES TO RETURN THU THROUGH AT LEAST FRIDAY NIGHT AS HIGH
PRESSURE SETTLES INTO THE REGION. STRONG MID/UPPER LEVEL RIDGE
OVER THE SOUTHWEST STATES THROUGH THIS WORK WEEK BEGINS TO BREAK
DOWN/FLATTEN THIS WEEKEND, AND MAY SEE DISTURBANCE TRACKING
INTO THE MIDWEST DURING THIS WEEKEND ESPECIALLY BY SUNDAY. A FEW
MODEL MEMBERS SHOWS SOME CONVECTION CHANCES AS EARLY AS
SATURDAY OVER THE IL RIVER VALLEY, WHILE MORE MEMBERS WAIT UNTIL
SUNDAY FOR CONVECTION CHANCES, THOUGH GEM AND ECMWF ARE DRY
THRU THE WEEKEND. NBM KEEPS POPS LOW THIS WEEKEND WITH 20% POPS
OVER IL RIVER VALLEY SAT AND SAT EVENING AND 20-40% POPS
OVERNIGHT SAT NIGHT AND SUNDAY.
THE CLIMATE PREDICTION CENTER (CPC) 8-14 DAY OUTLOOK FOR AUG
31-SEP 6TH HAS A 35-45% CHANCE OF ABOVE NORMAL TEMPERATURES
OVER CENTRAL/SE IL AND 33-40% BELOW NORMAL PRECIPITATION FROM
QUINCY TO DANVILLE NORTH AND TRENDING NEAR NORMAL SOUTH.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1245 PM CDT SUN AUG 23 2026
VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL NEXT 24 HOURS
THROUGH 18Z/1 PM MONDAY ACROSS THE CENTRAL IL AIRPORTS. THE ONLY
EXCEPTION WOULD BE IF ANY PATCHY SHALLOW GROUND FOG DEVELOPS
LATE TONIGHT/EARLY MON MORNING. HREF HAS ONLY A 15-30% CHANCE
OF VISIBILITIES GETTING TO 5 MILES OR LESS FROM 09Z-14Z OVER
CENTRAL IL AIRPORTS. BEST CHANCES OF FOG WILL BE NEAR THE RIVER
VALLEYS AND LOW LYING RURAL AREAS. DIURNALLY DRIVEN FEW TO
SCATTERED CUMULUS CLOUDS WITH BASES OF 4-6K FT THIS AFTERNOON
TO DISSIPATE AT SUNSET AND COULD REAPPEAR AFTER 16Z MON. WEAK
1020 MB HIGH PRESSURE OVER CENTRAL/NORTHERN MO AND RIDGING INTO
CENTRAL IOWA AND UPPER MS RIVER VALLEY, TO DRIFT OVER THE
CENTRAL OH RIVER VALLEY MONDAY MORNING WHILE RIDGING BACK INTO
NORTHEAST IL. NW WINDS 5-10 KTS THIS AFTERNOON (ISOLATED GUSTS
TO 15 KTS EARLY LIKE AT DEC) TO DIMINISHING LIGHT AND VARIABLE
TO CALM TONIGHT AFTER SUNSET. WINDS REMAIN LIGHT MONDAY MORNING
AND COULD BE VARIABLE DIRECTION YET WITH WEAK HIGH PRESSURE
RIDGE NEARBY.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...07
DISCUSSION...07
AVIATION...07
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