912
FXUS63 KILX 261602
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1102 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.
UPDATE
ISSUED AT 1050 AM CDT FRI JUN 26 2026
UPDATED THE FORECAST TODAY AND EVENING TO ADDRESS CHANCES OF
SHOWERS AND ISOLATED THUNDERSTORMS. THE HEAVIER RAINFALL SO FAR
TODAY HAS BEEN SOUTH OF I-70 WHERE POCKETS OF 1-2 INCHES OF RAIN
SINCE THU AFTERNOON. MUCH OF CENTRAL IL ONLY SEEING AROUND A
TENTH INCH OR LESS WITH POCKETS OF QUARTER TO A THIRD INCH RAIN.
THERE HAS BEEN AN UPTICK IN SHOWER COVERAGE AND INTENSITY PAST
HOUR OR SO AND EXPECT MORE WIDESPREAD SHOWERS WITH SOME
THUNDERSTORMS POSSIBLE WHICH COULD PRODUCE A FEW PERIODS OF
MODERATE TO HEAVIER RAIN SHOWERS. SPC DAY1 OUTLOOK HAS SLIGHT TO
MARGINAL RISK OF SEVERE STORMS OVER CLAY, RICHLAND, LAWRENCE
AND SOUTHERN REACHES OF JASPER AND CRAWFORD COUNTIES THIS
AFTERNOON AND EARLY EVENING. THE SLIGHT RISK AREA OVER MUCH OF
CLAY, RICHLAND AND LAWRENCE COUNTIES HAS 2 TO LESS THAN 5% RISK
OF TORNADOES AND 15% RISK OF DAMAGING WINDS. THE STRONGER
INSTABILITY HAS BEEN SOUTH OF CWA SO FAR TODAY, BUT SOME OF THIS
UNSTABLE AIR WILL MOVE NORTHWARD INTO SOUTHEAST IL DURING THIS
AFTERNOON AS SOUTHEAST IL REMAINS IN THE WARM SECTOR WITH WARM
FRONT ABOUT AS FAR NORTH AS A SHELBYVILLE TO PARIS LINE. THE
FLOOD WATCH OVER CENTRAL AND SOUTHERN PARTS OF CWA GOES INTO SAT
MORNING, BUT MAY BE ABLE TO END PART OF IT EARLY ESPECIALLY
NORTHERN/NW SECTIONS OF IT. PW VALUES RANGE FROM 1.5 INCHES FAR
NW CWA TO AROUND 2 INCHES SW CWA AND WILL SEE PW INCREASING TO
1.75 TO 2.2 INCHES DURING THIS AFTERNOON AND EARLY EVENING AS
LOW PRESSURE IN SOUTHEAST KS MOVES INTO CENTRAL MO AND
APPROACHES ST LOUIS AREA EARLY THIS EVENING.
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 /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 552 AM CDT FRI JUN 26 2026
10Z/5AM OBS SHOW VFR CEILINGS PERSISTING AT THE CENTRAL ILLINOIS
TERMINALS: HOWEVER, POCKETS OF IFR ARE EVIDENT ALONG I-70
WESTWARD INTO CENTRAL/SOUTHERN MISSOURI. AS THE ATMOSPHERE
MOISTENS FROM THE TOP-DOWN AND SHOWERS BECOME MORE WIDESPREAD,
CEILINGS WILL LOWER AS THE MORNING PROGRESSES. THE LATEST CAMS
HAVE SLOWED THE PROCESS BY A COUPLE OF HOURS WITH IFR DEVELOPING
AT KSPI BY 15Z AND FURTHER E/NE TO KDEC BY 16Z AND KCMI BY
AROUND 17Z. WITH THE BULK OF THE HEAVIER SHOWERS MOSTLY
ALONG/SOUTH OF THE I-72 CORRIDOR, THE NORTHERN SITES MAY TAKE
UNTIL LATE AFTERNOON OR EARLY EVENING TO LOWER TO IFR. THE
SHOWERS WILL GRADUALLY SHIFT EAST OF THE TERMINALS THIS EVENING,
WITH OVERCAST CONDITIONS LINGERING THROUGH 12Z SAT. WHILE A FEW
MODELS SUGGEST FOG/LOWERED VISBYS, THINK NE WINDS OF 5-10KT WILL
KEEP THE ATMOSPHERE MIXED AND RESULT IN A FURTHER LOWERING OF
THE CLOUD DECK TO 500FT OR LESS FROM MID-EVENING THROUGH THE
OVERNIGHT HOURS.
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH SATURDAY AFTERNOON FOR ILZ049>057-061>063-
066>068-071>073.
KEY MESSAGES...BARNES
UPDATE...07
DISCUSSION...BARNES
AVIATION...BARNES
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