978
FXUS63 KILX 150029
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
729 PM CDT TUE APR 14 2026
KEY MESSAGES
- PERIODS OF THUNDERSTORMS WILL CONTINUE THROUGH EARLY SATURDAY.
A 15-30% RISK FOR SEVERE WEATHER EXISTS THIS AFTERNOON,
TOMORROW NIGHT, AND LATE FRIDAY INTO SATURDAY. THE PRIMARY
RISKS THIS AFTERNOON WILL BE LARGE HAIL AND DAMAGING WINDS.
- WITH ANY TRAINING STORMS, HEAVY RAINFALL MAY RESULT IN LOCALIZED
FLOODING. THERE IS A LEVEL 2 OF 5 (SLIGHT) RISK FOR EXCESSIVE
RAINFALL THIS EVENING NORTHEAST OF A ROUGHLY GALESBURG TO
MATTOON LINE.
- AFTER A WARM WORK WEEK, CONDITIONS WILL TURN SHARPLY COOLER ON
SATURDAY. THERE WILL BE A LOW (20-30%) CHANCE FOR FROST
SATURDAY NIGHT NORTH OF I-70, AND A HIGHER CHANCE AREA-WIDE
SUNDAY NIGHT.
UPDATE
ISSUED AT 728 PM CDT TUE APR 14 2026
WE CONTINUE TO CLOSELY MONITOR STORM POTENTIAL ACROSS CENTRAL
ILLINOIS THIS EVENING, HOWEVER, THE THREAT REMAINS BEST ACROSS
NORTHERN ILLINOIS IN THE NEAR TERM. LOCALLY, VERY UNSTABLE
CONDITIONS (MLCAPE IN EXCESS OF 2000 J/KG) ARE IN PLACE AS
SAMPLED BY BOTH 18Z AND 00Z SOUNDINGS, ALBEIT STRONGLY CAPPED AT
18Z AROUND 800MB. WHILE THE CAP HAS LARGELY ERODED, THE EARLY
AFTERNOON SHORTWAVE TROUGH HAS LEFT SUBSIDENCE IN ITS WAKE
ACROSS CENTRAL ILLINOIS THIS EVENING, WHICH WHEN COUPLED WITH
LOSS OF PEAK DAYTIME HEATING, HAS RESULTED IN DRAMATIC THINNING
OF THE CUMULUS FIELD ACROSS THE CENTRAL PART OF THE STATE. GIVEN
THE LACK OF FORCING, LOWERED POPS CONSIDERABLY TO AROUND 20%
ACROSS CENTRAL ILLINOIS THROUGH THE REMAINDER OF THE EVENING. IF
ON THE OFF CHANCE A STORM IS ABLE TO DEVELOP (PERHAPS
ASSOCIATED WITH OUTFLOW FROM NORTHERN STORMS OR STRENGTHENING
LOW LEVEL JET), SHEAR AND INSTABILITY REMAIN FAVORABLE FOR ANY
STORMS TO BE SEVERE.
DISCUSSION
ISSUED AT 133 PM CDT TUE APR 14 2026
***** BOOM OR BUST CONVECTIVE SCENARIO THIS AFTERNOON *****
AT 1PM, A WARM AIRMASS WAS IN PLACE ACROSS CENTRAL AND SOUTHEAST
ILLINOIS WITH TEMPERATURES IN THE UPPER 70S TO LOW 80S. GULF
MOISTURE CONTINUES TO SURGE INTO THE REGION ON 15-20 (GUSTING TO 30)
MPH SOUTHWEST BREEZES, WITH DEWPOINTS CURRENTLY IN THE MID 60S.
CONSEQUENTLY, THE AIRMASS IS BECOMING INCREASINGLY UNSTABLE WITH RAP
MESOANALYSIS INDICATING 1500-3000 J/KG SBCAPE. A CAPPING INVERSION
SHOULD PREVENT CONVECTIVE INITIATION UNLESS AND UNTIL A TRIGGER
LIFTS PARCELS TO THE LFC, WHICH AT THIS POINT REMAINS UNCLEAR.
RECENT ITERATIONS OF THE HRRR AND SEVERAL MEMBERS OF THE 12Z REFS
SUGGEST THAT CAP WILL BREAK, RESULTING IN EXPLOSIVE CONVECTIVE
DEVELOPMENT AND SCATTERED SEVERE WEATHER ACROSS THE CWA BY MID
AFTERNOON. HOWEVER, ABOUT 60-70% OF CAMS KEEP THE CAP IN PLACE
THROUGHOUT THE EVENING - MAINTAINING WARM AND BREEZY CONDITIONS.
THE 18Z RAOB CONFIRMS THIS NOTION, DEPICTING A 3 DEGC CAPPING
INVERSION AROUND 800MB WHICH WOULD TAKE A LOT OF FORCING TO
OVERCOME. GIVEN THE PARAMETER SPACE FOR SEVERE WEATHER IS
FORECAST TO BECOME VOLATILE OVER THE NEXT FEW HOURS, WITH
SBCAPES CLIMBING TO 2500-4000 J/KG, 700-500 LAPSE RATES REACHING
8-8.5C/KM, AND 45-55 KT EFFECTIVE BULK WIND SHEAR, ANY STORMS
THAT FORM WOULD POSE A RISK FOR SEVERE WEATHER, ESPECIALLY LARGE
HAIL WHERE STORM RELATIVE INFLOW (FROM THE SSW/SW) IS UNIMPEDED
IN RIGHT- MOVING SUPERCELLS (FAVORED BY CLOCKWISE CURVED
HODOGRAPHS). IN ADDITION, A FEW OF THE MORE BULLISH MODELS SHOW
LOCALIZED POCKETS OF 3+ INCHES OF RAIN FALLING IN A FEW HOURS
WITH TRAINING STORMS, WHICH COULD RESULT IN SOME HYDROLOGICAL
ISSUES; ACCORDINGLY, WPC HAS EXPANDED THE LEVEL 2 OF 5 (SLIGHT)
RISK FOR EXCESSIVE RAINFALL SOUTHWARD INTO MUCH OF OUR CWA.
WE'LL BE KEEPING A CLOSE EYE ON MESOSCALE TRENDS THIS AFTERNOON
TO ASSESS THE POTENTIAL AND ISSUE ANY NECESSARY WARNINGS.
***** MORE NUMEROUS SHOWERS AND STORMS TOMORROW *****
WE'LL LIKELY (50-70% CHANCE) HAVE A FEW MORE STORMS OVERNIGHT
TONIGHT AS A WEAKENING MCS LIFTS UP INTO OUR AREA FROM NORTHEAST
MISSOURI. WE MAY END UP NEEDING SOME SHORT-FUSED WIND HEADLINE IF
THE HRRR AND RRFS ARE CORRECT IN THEIR DEPICTION OF A MESO-HIGH
FEATURE IMPACTING OUR WEST/SOUTHWEST COUNTIES BETWEEN 11PM AND 4AM,
THOUGH CONFIDENCE IN THIS SCENARIO IS ALSO LOW.
THE UPPER LEVEL LOW WILL SLOWLY APPROACH OUR AREA TOMORROW, WITH
CONTINUED WARM ADVECTION AHEAD OF IT BRINGING WAVES OF THUNDERSTORMS
THROUGH THE PRAIRIE STATE. IT APPEARS INSTABILITY WILL BE A BIT
WEAKER TOMORROW DUE TO WIDESPREAD CLOUDS AND SCATTERED STORMS
LIMITING SURFACE HEATING, THOUGH THE RISK FOR SEVERE WEATHER WILL
INCREASE DURING THE LATE EVENING OR EARLY OVERNIGHT PERIOD (8PM-2AM)
WEST OF I-55 WHERE A FEW CAMS BRING A WEAKENING LINE OF STORMS
CAPABLE OF LOCALLY SEVERE WINDS.
***** DRY THURSDAY(?), STORMS RETURN FRIDAY NIGHT *****
A WEAK COLD FRONT WILL SETTLE ACROSS THE DISTRICT ON THURSDAY,
BRINGING A MOMENT'S REPOSE FROM THE ACTIVE PATTERN. HOWEVER, THE
FRONT WILL LIFT BACK NORTH THURSDAY NIGHT INTO FRIDAY, WHEN
INSTABILITY WILL BUILD AHEAD OF A MORE POTENT KINEMATIC SYSTEM. AS
WITH TODAY, WE'LL BE IN THE WARM SECTOR ON FRIDAY, SO A VOLATILE
THERMODYNAMIC ENVIRONMENT WOULD SUPPORT SEVERE WEATHER IF A TRIGGER
RUPTURES THE CAPPING INVERSION. OTHERWISE, MORE NUMEROUS SHOWERS AND
STORMS WILL PASS THROUGH THE AREA ALONG THE COLD FRONT SOMETIME LATE
FRIDAY NIGHT OR SATURDAY MORNING. WHILE THIS IS NOT A DIURNALLY
FAVORABLE PERIOD FOR SEVERE WEATHER, THE STRONG FORCING WITH THE
COLD FRONT AND 45-55 KT DEEP LAYER SHEAR COULD RESULT IN AT LEAST
SCATTERED SEVERE WINDS IF A MATURE LINE OF STORMS ENTERS OUR AREA
FROM THE WEST FRIDAY NIGHT...OR DEVELOPS ALONG THE COLD FRONT IN
EASTERN ILLINOIS ON SATURDAY.
***** COOLER WEATHER RETURNS SATURDAY *****
A COLD FRONT WILL CROSS THE AREA SOMETIME ON SATURDAY, WITH STIFF
WEST WINDS USHERING IN A MORE SEASONABLY COOL AIRMASS FOR THE SECOND
HALF OF THE WEEKEND. NBM INDICATES A 30-50% CHANCE LOW TEMPERATURES
BY SATURDAY NIGHT FALL TO 36 DEG OR COOLER NORTH OF I-70, THOUGH
WINDS SHOULD REMAIN ELEVATED TO PREVENT FROST FORMATION. THE BETTER
OPPORTUNITY WILL BE SUNDAY NIGHT, WHEN NBM CHANCES ARE 30-60% AREA-
WIDE FOR SUB 37 DEGF LOWS AND WINDS SHOULD BE CALM WITH SURFACE HIGH
PRESSURE PARKED ACROSS THE CWA. PROTECTIVE ACTION MAY BE NEEDED TO
PREVENT FROST FROM DAMAGING TENDER VEGETATION.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 603 PM CDT TUE APR 14 2026
A TROUGH OF LOW PRESSURE WILL GENERALLY REMAIN DRAPED ACROSS
IOWA INTO SOUTHERN WISCONSIN THROUGH THE PERIOD. ACROSS
CENTRAL ILLINOIS, MODERATE S/SSW WINDS WILL CONTINUE THROUGH THE
PERIOD WITH GUSTS IN THE 20-30KT RANGE MUCH OF THE TIME.
UNSTABLE AND UNSETTLED CONDITIONS WILL BE IN PLACE; HOWEVER,
WITH NO NOTABLE FORCING MECHANISM ACROSS THE LOCAL AREA,
SPECIFIC TIMING OF PRECIP CHANCES REMAINS DIFFICULT TO PIN DOWN.
IN THE WAKE OF AN INITIAL SHORTWAVE AND ROUND OF STORMS NOW
OVER IN, CENTRAL IL IS FAVORED TO REMAIN DRY THIS EVENING AND
OVERNIGHT, BUT THERE REMAINS A LOW (20%) CHANCE FOR STORMS.
ADDITIONAL ROUNDS OF SHOWERS AND STORMS ARE POSSIBLE THROUGH THE
DAY WEDNESDAY, BUT CONFIDENCE IN SPECIFICS REMAINS LOW AND
ANTICIPATE THAT THERE WILL BE TIMING ADJUSTMENTS AS THE PICTURE
BECOMES MORE CLEAR.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BUMGARDNER
UPDATE...DEUBELBEISS
DISCUSSION...BUMGARDNER
AVIATION...DEUBELBEISS
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