681
FXUS63 KILX 110515
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1215 AM CDT SUN OCT 11 2026
KEY MESSAGES
- THERE IS A DIMINISHING THREAT OF RAIN FROM THE REMNANTS OF
ISAIAS TONIGHT INTO SUNDAY IN OUR FORECAST AREA, WITH RAIN
CHANCES (20-30%) CONFINED TO A SMALLER PORTION OF SOUTHEAST
ILLINOIS.
- NEAR-RECORD WARMTH ARRIVES MONDAY, OCTOBER 12, WITH AFTERNOON
HIGH TEMPERATURES SURGING INTO THE UPPER 80S TO LOWER 90S.
TUESDAY LOOKS EQUALLY AS WARM FOR OUR COUNTIES SOUTH OF I-72.
- AN EXTENDED PERIOD OF RAIN CHANCES IS ON TRACK TUESDAY NIGHT THROUGH
THURSDAY. SEVERE WEATHER POTENTIAL IS UNCERTAIN BUT APPEARS
LOW AT THIS POINT.
- MUCH COLDER AIR WILL ARRIVE FOR THE WEEKEND OF OCTOBER 17-18,
WITH OUR FIRST APPROACH TOWARD PATCHY FROST SATURDAY NIGHT AND
ESPECIALLY SUNDAY NIGHT.
DISCUSSION
ISSUED AT 208 PM CDT SAT OCT 10 2026
THE TREND OF LOWERING POPS AND QPF TONIGHT INTO SUNDAY WILL
CONTINUE WITH THIS UPDATE. THE REMNANTS OF HURRICANE ISAIAS ARE
CURVING TO THE NORTHEAST SOONER, AND THE WESTWARD EXPANSION OF
THE PRECIP SHIELD WILL ONLY BE INTO OUR CWA THIS EVENING, WITH
DRY AIR DISSIPATING THE PRECIP POTENTIAL. THERE IS SOLID
AGREEMENT IN THE CAMS ON THAT SCENARIO (HRRR, RAP, HREF, AND
RRFS). THE PRIMARY FORECAST SOLUTION ADOPTS A CONSENSUS BLEND
OF THE HREF AND HRRR, KEEPING LOW-END PRECIPITATION CHANCES
(2030%) RESTRICTED TO FAR SOUTHEAST ILLINOIS WHILE CENTRAL
ILLINOIS REMAINS DRY.
GLOBAL DETERMINISTIC MODELS (GFS, ECMWF, ECMWF-AI) AND THEIR
RESPECTIVE ENSEMBLE SUITES (GEFS, LREF) ARE IN TIGHT ALIGNMENT
REGARDING AN UNSEASONABLY STRONG THERMAL RIDGE PEAKING ON
MONDAY, OCTOBER 12 AND NOW EXTENDING INTO TUESDAY. NBM GUIDANCE
INDICATES HIGH CONFIDENCE IN HIGH TEMPERATURES REACHING 88F TO
92F ON MONDAY AND THAT SAME TEMP RANGE SOUTH OF I-72 ON
TUESDAY, WHICH WILL CHALLENGE DAILY RECORD HIGHS ACROSS CENTRAL
ILLINOIS CLIMATE SITES.
FOR TUESDAY NIGHT THROUGH THURSDAY, MINOR TIMING DISCREPANCIES
EXIST BETWEEN THE GFS AND ECMWF/ECMWF-AI. THE GFS IS SLIGHTLY
FASTER WITH COLD FRONT PROGRESSION ON TUESDAY, WHEREAS THE
ECMWF AND ECMWF-AI HOLD THE FRONTAL ZONE NEARLY STATIONARY
PARALLEL TO UPPER-LEVEL SOUTHWESTERLY FLOW THROUGH WEDNESDAY
NIGHT. DESI LREF ENSEMBLE PROBABILITIES HIGHLIGHT A 6075%
CHANCE OF CUMULATIVE RAINFALL EXCEEDING 1.50 INCHES ACROSS
CENTRAL AND EAST-CENTRAL ILLINOIS. HEAVY RAINFALL POTENTIAL IS
SUPPORTED BY PWAT VALUES EXCEEDING 1.6 INCHES (ABOVE THE 90TH
PERCENTILE FOR MID-OCTOBER). SPC CONVECTIVE OUTLOOKS, BACKED BY
CIPS AND CSU MACHINE LEARNING SEVERE PROBABILITY GUIDANCE,
INDICATE SOME RISK FOR SEVERE THUNDERSTORMS ALONG AND AHEAD OF
THE BOUNDARY ON WEDNESDAY, BUT MAINLY JUST WEST OF OUR CWA. WPC
EXCESSIVE RAINFALL OUTLOOKS (ERO) HIGHLIGHT A MARGINAL TO SLIGHT
RISK FOR FLASH FLOODING.
FOLLOWING FRONTAL PASSAGE THURSDAY NIGHT, A HIGH-AMPLITUDE
CANADIAN UPPER TROUGH DIGS INTO THE CENTRAL AND EASTERN UNITED
STATES. ENSEMBLE GUIDANCE DISPLAYS REMARKABLE CONSISTENCY
REGARDING AN UNSEASONABLY COLD AIRMASS INTRUDING INTO THE
REGION. 850 MB TEMPERATURES DROP INTO THE -2C TO -8C RANGE BY
SATURDAY, OCTOBER 17. THAT COULD SUPPORT PATCHY FROST
DEVELOPING IN LOW LYING AREAS SATURDAY NIGHT. A BETTER CHANCE
FOR PATCHY FROST LOOKS TO COME NEXT SUNDAY NIGHT.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1215 AM CDT SUN OCT 11 2026
AREA OF CEILINGS JUST BELOW 3,000 FEET IS LOCATED JUST SOUTHEAST
OF KCMI. NIGHTTIME MICROPHYSICS SATELLITE DATA HAS SHOWN SOME
EROSION ON THE NORTHWEST EDGE, AND BLENDED MODEL GUIDANCE
SUGGESTS NOT MUCH OF AN ADDITIONAL PUSH NORTHWEST. CURRENTLY
FEEL THAT THIS WILL NOT REACH KCMI, THOUGH IT WILL BE A CLOSE
CALL, AND ANY MVFR CONDITIONS WILL BE TRANSIENT THROUGH ABOUT
09Z.
IN GENERAL, VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS OVER
CENTRAL ILLINOIS, WITH MAINLY HIGH-BASED CLOUDS DURING THE
BEGINNING AND ENDING PORTIONS OF THE FORECAST PERIOD.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...SHIMON
DISCUSSION...SHIMON
AVIATION...GEELHART
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