300
FXUS63 KILX 201044
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
544 AM CDT SAT JUN 20 2026
KEY MESSAGES
- WIDESPREAD RAIN WILL OCCUR ON SUNDAY. A FLOOD WATCH HAS BEEN
ISSUED ROUGHLY FROM MACOMB TO DANVILLE AND SOUTHWARD, WHERE
THE NBM INDICATES A 30-50% CHANCE OF RAINFALL AMOUNTS
EXCEEDING 3".
- SEVERE STORMS ARE POSSIBLE ON SUNDAY, WITH A SLIGHT RISK
(LEVEL 2 OF 5) ALONG AND SOUTH OF A JACKSONVILLE TO
CHARLESTON LINE, AND A MARGINAL RISK (LEVEL 1 OF 5) TO THE
NORTH.
DISCUSSION
ISSUED AT 249 AM CDT SAT JUN 20 2026
REGIONAL MOSAIC SHOWS A FEW SHOWERS PERSIST NORTH OF
I-72/DANVILLE AS OF 230AM/0730Z SAT, DRIVEN IN PART BY WEAK
FGEN. KEPT SOME LOW POPS IN THE FORECAST THROUGH 7-8AM FOR THIS
ACTIVITY. OTHERWISE, NO WEATHER IMPACTS ARE EXPECTED ON SAT WITH
PARTLY CLOUDY SKIES AND HIGHS IN THE UPPER 70S TO LOW 80S. MUCH
OF THE FORECAST ATTENTION REMAINS ON SUNDAY'S SYSTEM AND THE
POTENTIAL FOR BOTH HEAVY RAIN AND SEVERE STORMS.
*** FLOOD WATCH IN EFFECT SUNDAY ***
A SHORTWAVE CURRENTLY LOCATED OVER THE INTERMOUNTAIN WEST IS SET
TO EMERGE TODAY AND AID CONVECTIVE DEVELOPMENT ACROSS NE/KS,
LEADING TO AN MCS APPROACHING IL FROM THE WEST BY SUN MORNING.
SW WINDS WILL FEED RICH MOISTURE INTO THE SYSTEM, WITH VERY HIGH
PWATS EXCEEDING 2". THERE IS STILL UNCERTAINTY AS TO THE EXACT
TRACK OF THE MCS SUN AM, WHICH IMPACTS BOTH THE HEAVY RAIN AND
SEVERE STORM FORECAST. OTHER SYNOPTIC SCALE SOURCES FOR ASCENT,
SUCH AS DPVA FROM THE APPROACHING LOW AND ISENTROPIC UPGLIDE
NEAR THE WARM FRONT, WILL RESULT IN WIDESPREAD RAIN DURING THE
DAY SUN.
UNSEASONABLY STRONG WIND FIELDS MAY KEEP INDIVIDUAL CONVECTIVE
ELEMENTS PROGRESSIVE, BUT WITH AN EAST-WEST MOTION TO THE LARGER
SYSTEM AND A ROUGHLY EAST-WEST ORIENTED FRONT, THE EXPECTATION
IS A CORRIDOR OF 2-3"+ RAINFALL WILL OCCUR. THE LATEST NBM PROBS
OF EXCEEDING 3" OF RAIN ARE MAXIMIZED ROUGHLY ALONG A
QUINCY/MACOMB TO DANVILLE/PARIS CORRIDOR (30-50%), WHICH IS
SIMILAR TO WHERE THE HIGHEST HREF LPMM VALUES OCCUR. THE HREF
SHOWS POTENTIAL FOR LOCALIZED AMOUNTS IN EXCESS OF 4 INCHES.
IN ADDITION TO THE HEAVY RAIN SIGNAL, SOILS REMAIN SATURATED WITH 50-
70% SOIL MOISTURE (0-100CM) PER NASA SPORT, AREA RIVERS AND
STREAMS ARE SWOLLEN WITH NUMEROUS RIVERS NEARING OR INTO MINOR
FLOOD STAGE CURRENTLY, AND MANY FIELDS STILL HAVE STANDING WATER
AFTER THE PREVIOUS RAIN EVENT. THIS RESULTS IN LOWER THAN
NORMAL RAIN NEEDED FOR FLASH FLOODING, WITH 3-HR FFG LESS THAN
2" ACROSS MUCH OF THE AREA. THE NATIONAL WATER MODEL DEPICTS A
25-50% CHANCE OF RAPID ONSET FLOODING ACROSS PORTIONS OF CENTRAL
IL.
COLLECTIVELY, THESE CONSIDERATIONS WERE ENOUGH TO WARRANT AN
UPGRADE TO A MODERATE RISK (LEVEL 3 OF 4) OF EXCESSIVE RAINFALL
FOR PORTIONS OF THE AREA ON SUNDAY, AND A FLOOD WATCH WAS
ISSUED FROM FULTON TO LOGAN TO VERMILION COUNTIES SOUTHWARD.
CONSIDERED INCLUDING ANOTHER TIER OF COUNTIES NORTHWARD (TO
ENCOMPASS PEORIA AND BLOOMINGTON- NORMAL), BUT OPTED TO KEEP THE
WATCH CONFINED CLOSER TO THE HIGHEST NBM/HREF PROBS FOR NOW.
WATCH EXPANSIONS MAY BE NEEDED PENDING EVALUATION OF FUTURE
GUIDANCE. THE FLOOD WATCH EXPIRES AT 06Z MON (1 AM), BY WHICH
POINT MOST, IF NOT ALL, OF THE PRECIP SHOULD BE SOUTH/EAST OF
THE FORECAST AREA.
*** CONDITIONAL SEVERE STORM THREAT SUNDAY ***
DUE TO SEASONABLY HIGH WIND SHEAR (~40 KTS) ASSOCIATED WITH THE
SYSTEM ON SUNDAY, THERE REMAINS A CONDITIONAL, BUT LOW
CONFIDENCE, SEVERE STORM RISK. CONFIDENCE IS LOWER DUE TO AM
STORMS ASSOCIATED WITH THE INCOMING MCS, AND UNCERTAINTY AS TO
WHAT DEGREE THE ATMOSPHERE RECOVERS DURING THE AFTERNOON. IF
THESE MORNING STORMS PRODUCE AN OUTFLOW BOUNDARY, AND SUFFICIENT
AIRMASS RECOVERY OCCURS, A LOCALIZED CORRIDOR OF GREATER
TORNADO POTENTIAL COULD DEVELOP. BASED ON THE SLIGHT SOUTHWARD
TRENDS IN MODELS, THE SLIGHT RISK (LEVEL 2 OF 5) REMAINING SOUTH
OF I-72 (WITH A MARGINAL RISK TO THE NORTH) SEEMS APPROPRIATE.
IT'S WORTH NOTING THERE ARE STILL OUTLIER SOLUTIONS, SUCH AS THE
00Z NAMNEST, WHICH TRACK THE SFC LOW MUCH FURTHER NORTH AND
WOULD SUBSEQUENTLY BRING THE SEVERE RISK NORTHWARD. HOWEVER,
THAT PARTICULAR SOLUTION SEEMS UNREALISTICALLY WEAK WITH THE
MORNING MCS. ULTIMATELY, THE SEVERE STORM OUTLOOK WILL REMAIN
FUZZY UNTIL WE SEE HOW STORMS EVOLVE SUNDAY MORNING.
*** REST OF THE WEEK ***
THE UPPER PATTERN WILL GENERALLY BE CHARACTERIZED BY RIDGING
OVER THE FOUR CORNERS REGION AND BROAD TROUGHING OVER THE UPPER
MIDWEST/NEW ENGLAND. MONDAY AND TUESDAY ARE EXPECTED TO BE
MOSTLY DRY IN THE WAKE OF OUR DEPARTING LOW, BUT NW FLOW ALOFT
WILL GUIDE ADDITIONAL WAVES TOWARDS THE REGION DURING THE LATTER
HALF OF THE WEEK. IN RESPONSE, THE NBM HAS OCCASIONAL LOW
(20-40%) PRECIP CHANCES FROM WED ONWARD. TEMPS REMAIN BELOW
NORMAL, BUT THERE ARE SIGNS THAT SUMMER-LIKE TEMPS RETURN AT THE END
OF JUNE. THE NBM PROBS OF TEMPS ABOVE 90 DEGF IS ESSENTIALLY 0%
AREA- WIDE THROUGH SAT JUN 27, BUT RISES TO 30-50% BY TUES JUN
30.
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
ILZ036-040>057-061>063-066>068-071>073.
KEY MESSAGES...ERWIN
DISCUSSION...ERWIN
AVIATION...ERWIN
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