333
FXUS63 KILX 060518
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1218 AM CDT SAT JUN 6 2026
KEY MESSAGES
- SCATTERED THUNDERSTORMS ARE POSSIBLE LATE TONIGHT THROUGH
SATURDAY. A FEW STORMS COULD HAVE THE POTENTIAL TO BECOME
STRONG TO SEVERE, POSING A RISK FOR HEAVY RAIN, LARGE HAIL,
AND DAMAGING WINDS.
- EXPECT A WARM AND HUMID SATURDAY WITH FEEL-LIKE TEMPERATURES
CLIMBING INTO THE LOW 90S.
- A STRONGER WARMING TREND ARRIVES TUESDAY THROUGH FRIDAY OF
NEXT WEEK, PUSHING HEAT INDEX VALUES NEAR 100 DEGREES.
DISCUSSION
ISSUED AT 241 PM CDT FRI JUN 5 2026
SURFACE ANALYSIS THIS AFTERNOON SHOWS RIDGING CENTERED OVER THE
SOUTHEAST US WITH SOUTHWEST RETURN FLOW OVER A GOOD PORTION OF THE
MIDWEST STATES. A DECAYING LINE OF SHOWERS MOVED THROUGH THE AREA
EARLIER TODAY WITH SOME ISOLATED ACTIVITY DEVELOPING IN ITS WAKE
OVER WESTERN AND CENTRAL ILLINOIS THIS AFTERNOON WHERE MODERATELY
STRONG INSTABILITY HAS DEVELOPED. DESPITE THIS, LITTLE FORCING
SHOULD LIMIT STORM ORGANIZATION THROUGH EARLY THIS EVENING. AN
APPROACHING COLD FRONT AND REMNANT OUTFLOW BOUNDARY WILL BE THE
FOCUS FOR THUNDERSTORM DEVELOPMENT FURTHER WEST OF HERE TONIGHT AS A
SHORTWAVE TROUGH AND LOW-LEVEL JET PROVIDE LARGE-SCALE ASCENT. THE
LATEST SUITE OF CAMS SUGGEST THE THUNDERSTORM ACTIVITY WILL SLIDE
EAST INTO NORTH-CENTRAL ILLINOIS LATE TONIGHT AFTER 1-2 AM (MAINLY
NEAR/NORTH OF I-74). THE 05.12Z HREF SHOWS 1-2K J/KG OF CAPE IN
PLACE NORTH OF I-72 OVERNIGHT, THOUGH THE BETTER SHEAR IS DISPLACED
WELL NORTH OF THE FORECAST AREA. DESPITE THIS, A FEW STORMS MAY
BECOME STRONG OVERNIGHT INTO SATURDAY MORNING AND POSE A THREAT FOR
ISOLATED LARGE HAIL AND DAMAGING WINDS. MORE NOTABLY, HEAVY RAIN
ASSOCIATED WITH THUNDERSTORMS COULD BE THE PRIMARY THREAT WITH
FORECAST PWATS OF 1.5 TO 2 INCHES AND WARM CLOUD DEPTHS OVER 3K
METERS - FAVORABLE FOR HIGH RAINFALL RATES. THE HREF'S 24 HOUR
PRECIPITATION LPMM SHOWS POCKETS OF 1-2" OF RAIN NEAR THE I-74
CORRIDOR THROUGH SATURDAY MORNING WITH WPC HIGHLIGHTING A MARGINAL
RISK FOR EXCESSIVE RAINFALL IN THIS SAME AREA.
SURFACE RIDGING BEGINS BUILDING IN FROM THE SOUTHWEST ON SATURDAY,
TURNING THINGS WARMER AND MORE HUMID FOR THE WEEKEND. LINGERING
CLOUD COVER MAY SUPPRESS AIR TEMPERATURES SOME ON SATURDAY, BUT ARE
STILL FORECAST TO CLIMB INTO THE MIDDLE 80S WITH DEWPOINTS
APPROACHING 70 DEGREES BY AFTERNOON, LEADING TO FEEL-LIKE
TEMPERATURES IN THE LOW 90S. THE OUTFLOW BOUNDARY FROM OVERNIGHT
STORMS WILL LINGER OVER CENTRAL ILLINOIS ON SATURDAY WITH CAMS
SUGGESTING STORMS REGENERATING ALONG IT BY LATE AFTERNOON/EVENING AS
SBCAPE APPROACHES 2000 J/KG. HOWEVER, WEAK SHEAR AND LARGE SCALE
SUBSIDENCE SHOULD MINIMIZE STORM ORGANIZATION. HAZARDS WITH ANY
STORMS THAT DO DEVELOP WILL BE HEAVY RAIN AND GUSTY WINDS AS STORMS
COLLAPSE.
UPPER RIDGING GETS PUSHED EAST BY SUNDAY AS A CLOSED UPPER LOW
APPROACHES FROM THE WEST. WIDESPREAD CLOUD COVER AND INCREASING
PRECIPITATION CHANCES WILL HOLD TEMPERATURES CLOSER TO NORMAL BOTH
SUNDAY AND MONDAY. UPPER RIDGING WILL BUILD OVER THE PLAINS STATES
EARLY NEXT WEEK PUSHING THE UPPER LOW OFF TO THE NORTHEAST,
RESULTING IN A BIG WARM UP IN TEMPERATURES BY THE MIDDLE TO END OF
NEXT WEEK. AIR TEMPERATURES LOOK TO CLIMB INTO THE UPPER 80S TO LOW
90S TUESDAY THROUGH FRIDAY, WITH HEAT INDICES APPROACHING 100
DEGREES. THE LREF (ENS, GEFS, GEPS) SHOWS A 20% CHANCE FOR HEAT
INDICES TO EXCEED 100 DEGREES WEDNESDAY THROUGH FRIDAY. THIS PAIRED
WITH LITTLE RELIEF IN TEMPERATURES OVERNIGHT COULD BECOME DANGEROUS,
ESPECIALLY FOR THOSE WHO HAVE LIMITED OR NO ACCESS TO INDOOR COOLING
SYSTEMS.
AVIATION /06Z TAFS THROUGH 06Z SUNDAY/
ISSUED AT 1218 AM CDT SAT JUN 6 2026
MAIN AVIATION CONCERN WILL BE WITH TIMING OF ANY THUNDERSTORM
ACTIVITY. AT 05Z, STORMS ARE MAINLY WELL INTO SOUTHERN IOWA,
THOUGH A FEW HAVE BEGUN PERCOLATING NEAR THE MISSISSIPPI RIVER.
SOME OVERALL UNCERTAINTY AS TO THE TIMING AND EASTWARD EXTENT OF
THIS ACTIVITY, AND WILL LIMIT ANY PROB30 MENTION IN THE SHORT
TERM TO KPIA/KBMI. THE STORMS ARE EXPECTED TO LAY OUT A BOUNDARY
THAT WILL SERVE AS FOCUS FOR RENEWED DEVELOPMENT FROM LATE
MORNING INTO THE AFTERNOON, PRIMARILY FROM KPIA-KCMI. ADDITIONAL
STORMS ARE POSSIBLE LATE IN THE PERIOD IN THIS SAME CORRIDOR.
OUTSIDE OF THE STORMS, VFR CONDITIONS ARE EXPECTED TO PREVAIL.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...NMA
DISCUSSION...NMA
AVIATION...GEELHART
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