809
FXUS63 KILX 260924
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
424 AM CDT FRI JUN 26 2026
KEY MESSAGES
- A FLOOD WATCH CONTINUES FOR LOCATIONS ALONG AND SOUTH OF A
JACKSONVILLE...TO DECATUR...TO PARIS LINE THROUGH SATURDAY
AFTERNOON.
- THE FIRST PROLONGED HEATWAVE OF THE SUMMER WILL ARRIVE NEXT
WEEK WHEN AIR TEMPERATURES RISE INTO THE 90S AND MAXIMUM HEAT
INDEX VALUES CLIMB WELL ABOVE 100 DEGREES SUNDAY THROUGH AT
LEAST THURSDAY.
DISCUSSION
ISSUED AT 424 AM CDT FRI JUN 26 2026
*** LOCALLY HEAVY RAINFALL ***
THE RAIN EVENT HAS SO FAR UNDERPERFORMED AS 08Z/3AM RADAR
IMAGERY CONTINUES TO SHOW JUST SPOTTY SHOWERS ACROSS CENTRAL
ILLINOIS. AS A 40-45KT 850MB JET STREAK CURRENTLY ORIENTED FROM
TEXAS NORTHWARD TO KANSAS SHIFTS TOWARD SOUTHERN ILLINOIS,
SHOWERS AND THUNDERSTORMS WILL BECOME MORE NUMEROUS AS THE
MORNING PROGRESSES AND WILL LINGER THROUGHOUT THE AFTERNOON.
GIVEN PRECIPITABLE WATER VALUES INCREASING INTO THE 2.00-2.25
RANGE AND FORECAST SOUNDINGS INDICATING A DEEP WARM LAYER, THE
SHOWERS WILL BE EFFICIENT RAIN-PRODUCERS. AS A RESULT, AM
EXPECTING OCCASIONAL DOWNPOURS...PARTICULARLY ALONG/SOUTH OF A
JACKSONVILLE...TO DECATUR...TO PARIS LINE WHERE A FLOOD WATCH
WILL REMAIN IN EFFECT. STORM TOTAL RAINFALL TODAY THROUGH THIS
EVENING WILL RANGE FROM 1.50-2.50 ACROSS THIS AREA...WITH
ISOLATED HIGHER AMOUNTS FOCUSED ALONG/SOUTH OF I-70 WHERE A FEW
STRONG STORMS WILL BE POSSIBLE LATE THIS AFTERNOON. FURTHER
N/NW, RAINFALL AMOUNTS WILL DECREASE TO LESS THAN 1 INCH
ALONG/NORTHWEST OF A MACOMB TO BLOOMINGTON LINE. THE SHOWERS
WILL LINGER INTO THIS EVENING, THEN WILL GRADUALLY
DISSIPATE/COME TO AN END OVERNIGHT.
*** HOT WEATHER RETURNS ***
AFTER A FEW MORE SHOWERS/THUNDERSTORMS SATURDAY NIGHT, THE
HIGHLY ADVERTISED HEATWAVE WILL COMMENCE ACROSS CENTRAL ILLINOIS
ON SUNDAY. AS UPPER TROUGHING DIGS WEST OF THE ROCKIES,
PRONOUNCED DOWNSTREAM RIDGING WILL OCCUR OVER THE MIDWEST AND
OHIO RIVER VALLEY. WHILE THERE WAS INITIALLY SOME DOUBT
CONCERNING THE EXACT STRENGTH/ORIENTATION OF THE RIDGE, MODEL
SOLUTIONS HAVE BEEN CONSISTENTLY SHOWING A DOMINANT UPPER RIDGE
CENTERED OVER THE REGION FOR MUCH OF NEXT WEEK. AS UPPER HEIGHTS
RISE, THE PERSISTENT FRONTAL BOUNDARY DRAPED FROM THE OZARKS
INTO KENTUCKY WILL LIFT NORTHWARD ON SUNDAY...ALLOWING AFTERNOON
HIGH TEMPERATURES TO CLIMB INTO THE UPPER 80S AND LOWER 90S.
WHILE PEAK HEAT INDEX READINGS MAY ECLIPSE 100 DEGREES ACROSS
THE W/SW KILX CWA, THE REAL HEAT AND HUMIDITY WILL ARRIVE ON
MONDAY...THEN PERSIST THROUGH AT LEAST THURSDAY. EXPECT DAILY
HIGH TEMPERATURES IN THE LOWER TO MIDDLE 90S WITH OVERNIGHT LOWS
IN THE MIDDLE 70S. WITH DEWPOINTS HOVERING IN THE LOWER TO
MIDDLE 70S, HEAT INDEX VALUES WILL SOAR ABOVE 105 DEGREES.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1217 AM CDT FRI JUN 26 2026
A WARM FRONT LIFTING THROUGH THE AREA WILL STALL OUT OVER CENTRAL
ILLINOIS AND PROMOTE SCATTERED SHOWERS AND STORMS THROUGH A GOOD
PORTION OF THE TAF PERIOD. CEILINGS WILL QUICKLY DROP FROM MVFR TO
IFR BY LATER THIS MORNING. PRECIPITATION WILL COME TO AN END BY LATE
AFTERNOON OR EARLY EVENING, THOUGH PROBABILITIES ARE HIGH THAT
CEILINGS REMAIN BELOW 1K FT THROUGH FRIDAY NIGHT ESPECIALLY AT
AIRFIELDS CLOSEST TO THE FRONT (KSPI-KDEC-KCMI).
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH SATURDAY AFTERNOON FOR ILZ049>057-061>063-
066>068-071>073.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...NMA
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