761
FXUS63 KILX 190455
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1155 PM CDT TUE AUG 18 2026
KEY MESSAGES
- WHILE HEAVIER RAIN WITH AN OVERNIGHT THUNDERSTORM COMPLEX
STAYS TO OUR SOUTH, PERIODS OF SHOWERS AND A FEW THUNDERSTORMS
ARE EXPECTED LATE TONIGHT INTO WEDNESDAY MORNING.
- A PERSISTENT NORTHWEST FLOW WILL KEEP TEMPERATURES AND
HUMIDITY LEVELS IN CHECK THE NEXT SEVERAL DAYS, WITH HIGHS IN
THE UPPER 70S TO LOWER 80S COMMON.
DISCUSSION
ISSUED AT 125 PM CDT TUE AUG 18 2026
A GENERAL NORTHWEST UPPER FLOW WILL PREVAIL OVER THE NEXT
SEVERAL DAYS, AS A LARGE LOW OVER NORTHERN ONTARIO DRIFTS EAST
AND RIDGING BUILDS WEST OF THE ROCKIES. THIS WILL KEEP ANY SORT
OF HOT WEATHER AT BAY, WITH HIGH TEMPERATURES GENERALLY IN THE
UPPER 70S OR LOWER 80S INTO EARLY NEXT WEEK.
MORNING HIGH-RES MODELS DEVELOP AN MCS OVER NORTHWEST MISSOURI/
NORTHEAST KANSAS THIS EVENING, NEAR THE NOSE OF A 700 MB JET.
MORNING HIGH-RES GUIDANCE IS IN DECENT AGREEMENT WITH THE CORE
OF THE MCS PASSING JUST TO OUR SOUTH, THOUGH THE NAM-NEST HAS IT
SCRAPING AS FAR NORTH AS JACKSONVILLE AND SPRINGFIELD. REMNANTS
OF THIS MCS SHOULD REACH SOUTHEAST ILLINOIS EARLY WEDNESDAY
MORNING. ENSEMBLE GUIDANCE SUGGESTS THE HEAVIEST RAIN STAYING
SOUTH OF OUR AREA, THOUGH LOCALLY HEAVY RAIN SOUTH OF I-70
ISN'T OUT OF THE QUESTION AS PRECIPITABLE WATER VALUES IN THAT
AREA WILL BE CLOSE TO 2 INCHES. BY DAYBREAK, A SHORTWAVE WILL
BE DROPPING SOUTH INTO CENTRAL ILLINOIS, THOUGH LOITERING UNTIL
A MORE SUBSTANTIAL WAVE SWEEPS ACROSS EARLY THURSDAY. THIS
SECOND WAVE WILL BRING A PERIOD OF DRY CONDITIONS FOR LATE IN
THE WORK WEEK.
AS THE RIDGE BUILDS ACROSS THE WESTERN U.S. LATE THIS WEEK,
ANOTHER WEAK WAVE WILL SWEEP ACROSS THE MIDWEST, PRIOR TO A
DEEP UPPER TROUGH DIGGING TO OUR EAST. THIS MAY BRING A FEW
SHOWERS AND THUNDERSTORMS FRIDAY NIGHT INTO EARLY SATURDAY.
HOWEVER, ANY SUBSTANTIAL RAIN CHANCES SHOULD STAY TO OUR WEST
LATE WEEKEND INTO EARLY NEXT WEEK, WITH SURFACE HIGH PRESSURE
DOMINATING THE REGION.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1155 PM CDT TUE AUG 18 2026
CONVECTION IS EXPECTED TO PASS SOUTHWEST OF CENTRAL IL TONIGHT,
PROVIDING AN INCREASE IN HIGH CLOUDS. THE NEXT WAVE IS PROGGED
FOR WED AFTERNOON AND EVENING AND THIS LOOKS TO BE MORE FOCUSED
OVER THE CENTRAL IL TERMINALS. KEPT PROB30 TSRA MENTION FOR ALL
SITES AS COVERAGE AND LOCATION IS STILL LOW-MEDIUM CONFIDENCE,
BUT IF CURRENT TRENDS HOLD TEMPO AND PREDOMINANT GROUPS WILL BE
ADDED LATER. OTHERWISE, A BKN MVFR STRATOCU DECK LOOKS TO
DEVELOP OVER THE AREA WED MORNING, LIFTING TO VFR DURING EARLY
TO MID AFTERNOON.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...GEELHART
DISCUSSION...GEELHART
AVIATION...25
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