013
FXUS63 KILX 201747
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1247 PM CDT SAT JUN 20 2026
KEY MESSAGES
- WIDESPREAD RAIN WILL OCCUR ACROSS CENTRAL ILLINOIS ON SUNDAY.
AMOUNTS OF 1.50 TO 2.50 WILL BE COMMON...WITH ISOLATED HIGHER
TOTALS WEST OF THE I-55 CORRIDOR.
- THERE IS A SLIGHT RISK (LEVEL 2 OF 5) FOR SEVERE WEATHER ALONG
AND SOUTH OF A JACKSONVILLE TO DANVILLE LINE ON SUNDAY.
DISCUSSION
ISSUED AT 1247 PM CDT SAT JUN 20 2026
*** HEAVY RAINFALL ON SUNDAY ***
12Z JUN 20 CAMS STILL DISPLAY A HIGH DEGREE OF SPREAD
CONCERNING CONVECTIVE TRENDS/TIMING FOR SUNDAY: HOWEVER, THE
OVERALL SYNOPTIC PATTERN REMAINS STRONGLY SUPPORTIVE OF HEAVY
RAINFALL. CLUSTERS OF THUNDERSTORMS WILL FORM ACROSS NEBRASKA
AND NORTHERN KANSAS THIS EVENING, THEN WILL SPREAD ACROSS
IOWA/MISSOURI OVERNIGHT AND INTO WEST-CENTRAL ILLINOIS TOWARD
DAWN SUNDAY. BASED ON THE EXPECTED TRAJECTORY OF THE CONVECTION,
IT APPEARS LOCATIONS NORTH OF THE I-70 CORRIDOR WILL EXPERIENCE
THE HEAVIEST RAINFALL FROM SUNDAY MORNING THROUGH MID-AFTERNOON
BEFORE IT PUSHES FURTHER EASTWARD INTO INDIANA. GIVEN A STRONG
LOW-LEVEL JET STREAK TRANSPORTING COPIOUS MOISTURE NORTHWARD
AND PRECIPITABLE WATER VALUES INCREASING TO 2.00-2.25, THE
SHOWERS/STORMS WILL BE EFFICIENT RAIN-PRODUCERS. 3-HOUR FLASH
FLOOD GUIDANCE RANGES FROM 1.75 TO 2.50 AND AM CONCERNED THE
STRONGEST STORMS WILL BE CAPABLE OF PRODUCING THAT MUCH
RAINFALL. SINCE THE SOIL IS SATURATED AND WATER IS STILL
STANDING IN SOME AREA FIELDS, HAVE EXPANDED THE FLOOD WATCH TO
INCLUDE THE PEORIA AREA NORTHWARD. STORM TOTAL RAINFALL WILL
GENERALLY RANGE FROM 1.50 TO 2.50: HOWEVER, A FEW LOCATIONS
ALONG/WEST OF I-55 COULD POTENTIALLY APPROACH 3 INCHES.
*** SEVERE WEATHER RISK ON SUNDAY ***
AS THUNDERSTORMS SPILL INTO THE ILLINOIS RIVER VALLEY SUNDAY
MORNING, THEY WILL BE NON-SEVERE HEAVY-RAIN PRODUCERS. HOWEVER
AS THE ATMOSPHERE DESTABILIZES TO THE EAST AND SOUTH OF THE
STORMS, THERE IS GROWING CONCERN THAT SOME OF THE CELLS ALONG
THE SOUTHERN PERIPHERY OF THE RAIN AREA COULD BECOME STRONG TO
SEVERE DURING THE AFTERNOON. WHILE THE STRONGEST INSTABILITY
WILL REMAIN FURTHER SOUTH FROM THE OZARKS INTO THE OHIO RIVER
VALLEY WHERE SBCAPES WILL REACH 2000-3000J/KG, INCREASING
DEEP-LAYER SHEAR WITH 0-6KM VALUES CLIMBING ABOVE 40KT WILL
LIKELY BE SUFFICIENT TO PRODUCE ORGANIZED CONVECTION. WHILE CAMS
HAVE NOT YET HONED IN ON AN EXACT SOLUTION, AM MOST CONCERNED
ABOUT LOCATIONS ALONG/SOUTH OF A JACKSONVILLE TO DANVILLE LINE
WHERE LOW-LEVEL SHEAR WILL BE MAXIMIZED IN THE VICINITY OF THE
PREVAILING OUTFLOW BOUNDARY. DAMAGING WIND GUSTS OF AROUND 60MPH
AND HAIL LARGER THAN QUARTERS WILL BE THE PRIMARY RISKS:
HOWEVER, A FEW TORNADOES WILL ALSO BE POSSIBLE. 12Z HREF
SIGNIFICANT TORNADO PARAMETER (STP) VALUES RANGE FROM 1-1.5
ACROSS THIS AREA FROM ROUGHLY 1PM TO 9PM. WHILE THIS EVENT DOES
NOT APPEAR TO BE CLOSE TO THE MAGNITUDE OF JUNE 17, ALL SEVERE
HAZARDS WILL BE POSSIBLE ACROSS THE SOUTHERN KILX CWA DURING THE
AFTERNOON AND EVENING. STAY TUNED TO LATER FORECASTS FOR
ADDITIONAL DETAILS.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 543 AM CDT SAT JUN 20 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A MID-LEVEL
CLOUD DECK IS IN PLACE PRESENTLY, AND WHILE THIS WILL SHIFT
SOUTH TODAY, ADDITIONAL DIURNAL CUMULUS DEVELOPMENT WILL KEEP
SKIES PARTLY CLOUDY. NORTHWEST WINDS WILL BE AROUND 10 KTS
DURING THE DAY. LATE IN THE PERIOD, A SYSTEM APPROACHES FROM THE
WEST, RESULTING IN INCREASING MID-LEVEL CLOUD COVER AND A
CHANCE FOR SHOWERS AT KPIA/KSPI AFTER ABOUT 09Z. THE POTENTIAL
FOR RAIN, STORMS, AND LOW CEILINGS INCREASES AT ALL TERMINALS
AFTER 12Z SUN.
ILX WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM SUNDAY MORNING THROUGH LATE SUNDAY NIGHT FOR
ILZ027>031-036>038-040>057-061>063-066>068-071>073.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...ERWIN
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