026
FXUS63 KILX 140813
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
313 AM CDT TUE APR 14 2026
KEY MESSAGES
- THE STRETCH OF WARM WEATHER IS EXPECTED TO LAST THROUGH
FRIDAY, WITH DAILY TEMPERATURES CLIMBING NEAR 80 DEGREES, AND
AT TIMES, THE MID-80S. BREEZY WINDS, OCCASIONALLY REACHING
25-35 MPH, WILL ACCOMPANY THIS WARM PERIOD.
- THIS WEEK WILL BE RIDDLED WITH THUNDERSTORM POTENTIAL. TODAY,
WEDNESDAY, AND FRIDAY CURRENTLY EXHIBIT THE HIGHEST
PROBABILITY (15-30%) OF SEVERE WEATHER.
- THERE IS ALSO POTENTIAL FOR SUBSTANTIAL ACCUMULATIVE RAINFALL
THROUGHOUT THE WEEK, WITH OUR MULTI-MODEL ENSEMBLE PREDICTING
A MEDIUM (30-50%) CHANCE OF EXCEEDING 2 INCHES THROUGH
SATURDAY IN AREAS NORTH OF INTERSTATE 72.
DISCUSSION
ISSUED AT 301 AM CDT TUE APR 14 2026
SATELLITE IMAGERY REVEALS TWO KEY AREAS OF CONVECTION THIS
MORNING. FIRST, A CLUSTER OF DECAYING THUNDERSTORMS IN CENTRAL
MISSOURI, AS SHOWN BY WARMING CLOUD TOPS. THE ASSOCIATED
CONVECTIVELY-AUGMENTED SHORTWAVE IS ANTICIPATED TO MOVE EASTWARD
ALONG THE I-70 CORRIDOR INTO CENTRAL ILLINOIS LATER THIS
MORNING. SECOND, A PERSISTENT AREA OF CONVECTION IS SITUATED
FURTHER NORTH OVER NORTHEAST IOWA AND SOUTHERN WISCONSIN, NEAR
THE PRIMARY SURFACE BOUNDARY, WITH ITS OUTFLOW BOUNDARY SLOWLY
ADVANCING SOUTHWARD INTO NORTHERN ILLINOIS.
THE REGION SITUATED BETWEEN THESE TWO FEATURES REMAINS
FAVORABLE FOR RENEWED THUNDERSTORM DEVELOPMENT. A STRONG 40-50
KNOT LOW- LEVEL JET (LLJ) IS PRESENT, MAINTAINING A HEALTHY SINK
OF MUCAPE (1500-2000 J/KG). FURTHERMORE, THE EASTWARD-TRACKING
CONVECTIVELY-AUGMENTED SHORTWAVE IS EXPECTED TO BOOST EFFECTIVE
LAYER SHEAR TO NEARLY 40 KNOTS AND SUSTAIN FAVORABLE MID-LEVEL
LAPSE RATES.
GIVEN THIS COMBINATION OF SUFFICIENT CAPE, SHEAR, AND RESIDUAL
FORCING MECHANISMS, THE RE-IGNITION OF CONVECTION INTO CENTRAL
AND EAST-CENTRAL ILLINOIS IS CONSIDERED PLAUSIBLE THIS MORNING.
MODEL GUIDANCE, SPECIFICALLY THE HRRR AND RRFS, SUGGESTS THE
POTENTIAL DEVELOPMENT OF AN ELEVATED THUNDERSTORM CLUSTER. IF
THIS MATERIALIZES, THE PRIMARY CONVECTIVE HAZARD THROUGH MID-
MORNING WILL BE HAIL.
DESPITE THE DEVELOPMENT OF A HIGHLY VOLATILE ATMOSPHERE THIS
AFTERNOON, FEATURING SURFACE TEMPERATURES IN THE MID-80S, 60S
DEWPOINTS, FAVORABLE MID-LEVEL LAPSE RATES, AN INTENSIFYING MID-
LEVEL JET, AND ROBUST SBCAPE (2500-3500 J/KG), THE POTENTIAL FOR
THUNDERSTORMS REMAINS LOW. THIS IS PRIMARILY DUE TO A
PERSISTENT CAP, MAINTAINED BY RESIDUAL SUBSIDENCE AND MARGINAL
MID-LEVEL HEIGHT INCREASES FOLLOWING THE MORNING SHORTWAVE. THIS
CAP, PARTICULARLY IN THE 1-3 KM LAYER, COULD SIGNIFICANTLY
LIMIT, OR EVEN PREVENT, CONVECTIVE DEVELOPMENT.
SYNOPTIC FORCING TODAY APPEARS NEBULOUS, COMPOUNDING THE
FORECAST DIFFICULTY: THE MAIN SURFACE FRONT IS EXPECTED TO STAY
NORTH; THE LOCATION OF POTENTIAL CONVECTIVE OUTFLOWS IS UNKNOWN;
AND NO STRONG SHORTWAVE IS LIFTING ACROSS THE AREA. THIS HAS
LED TO SUBSTANTIAL UNCERTAINTY IN THE TIMING AND LOCATION OF
STORM INITIATION, WITH CAMS STRUGGLING TO ACCURATELY PREDICT
STORM EVOLUTION.
HOWEVER, IF UPDRAFTS MANAGE TO BREACH THE CAP LATER THIS
AFTERNOON OR EARLY EVENING, THE ENVIRONMENT IS PRIMED TO SUPPORT
SIGNIFICANT-SEVERE CONVECTIVE HAZARDS. THE PROFILE IS A CLASSIC
"LOADED GUN", BUT THE TRIGGER (FORCING) IS LARGELY MISSING, OR
AT LEAST UNKNOWN AT THE MOMENT.
REGARDLESS OF TODAY'S CONVECTIVE OUTCOME, THE LIKELIHOOD OF
WIDESPREAD CONVECTION INCREASES SIGNIFICANTLY BY WEDNESDAY
MORNING. THIS IS EXPECTED AS A LOW-LEVEL JET AXIS ESTABLISHES
ACROSS THE REGION AND A PRECEDING SHORTWAVE DISTURBANCE EJECTS
AHEAD OF A MORE POTENT TROUGH TRACKING ACROSS THE LEE OF THE
ROCKIES.
ADDITIONAL ROUNDS OF STORMS ARE THEN LIKELY THROUGH WEDNESDAY
EVENING AS THE MAIN TROUGH SWINGS ACROSS THE MID-MISSISSIPPI
VALLEY. A FAVORABLE CAPE/SHEAR ENVIRONMENT IS ANTICIPATED TO
SUPPORT ELEVATED SUPERCELL AND MULTICELL STRUCTURES OVER CENTRAL
ILLINOIS THROUGHOUT THE DAY, CAPABLE OF PRODUCING ALL SEVERE
HAZARDS, INCLUDING LOCALIZED HEAVY RAINFALL.
THURSDAY LOOKS TO BE A REGION-WIDE BREAK FROM STORMS DUE TO
SYNOPTIC-SCALE SUBSIDENCE MOVING IN BEHIND THE DEPARTING UPPER
TROUGH.
THUNDERSTORM ACTIVITY IS THEN EXPECTED TO RETURN OVER THE
WEEKEND, SPECIFICALLY FRIDAY NIGHT INTO SATURDAY. THIS IS
ASSOCIATED WITH A COMPACT SHORTWAVE TROUGH LIFTING ACROSS THE
MID-MISSISSIPPI VALLEY AHEAD OF A PIVOTING, MORE VIGOROUS TROUGH
AND ITS ACCOMPANYING COLD FRONT. THE CAPE/SHEAR PARAMETER SPACE
APPEARS VOLATILE ENOUGH TO SUPPORT AN ORGANIZED SEVERE
CONVECTIVE RISK, EVEN THOUGH THE FRONT APPEARS TO PASS DURING A
DIURNALLY UNFAVORABLE TIME.
FOLLOWING THE COLD FRONTAL PASSAGE, TEMPERATURES WILL COOL
SIGNIFICANTLY FROM SATURDAY NIGHT THROUGH MONDAY AS THE WARM,
MOIST AIR MASS FROM THE PREVIOUS WEEK IS FLUSHED OUT. THE LATEST
NBM DETERMINISTIC GUIDANCE SUPPORTS SUNDAY AFTERNOON HIGH
TEMPERATURES NEAR 60 DEGREES, WITH OVERNIGHT LOWS AROUND 40
DEGREES.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1205 AM CDT TUE APR 14 2026
A WEAK DISTURBANCE CROSSING THE REGION LATE TONIGHT WILL BRING A
1-2 HOUR WINDOW OF LOW -TSRA CHANCES TO CENTRAL IL. THE HIGHER
PROBABILITIES OF THIS OCCURRING ARE NEAR/NORTH OF THE I-74
CORRIDOR WHERE A PROB30 GROUP WAS INCLUDED. OTHERWISE, AS
DIURNAL HEATING COMMENCES, BKN MVFR CEILINGS ARE FORECAST TO
DEVELOP, ESPECIALLY AT KPIA-KBMI-KCMI, WITH LOWER PROBABILITIES
TO THE SOUTH. THESE SHOULD RISE ABOVE 3K FEET BY MIDDAY. AN
ISOLATED STORM CAN'T BE RULED OUT THIS AFTERNOON BUT
PROBABILITIES ARE TOO LOW TO MENTION IN THE TAF. SOUTHWEST WINDS
WILL REMAIN GUSTY THROUGH THE PERIOD, NEAR 25 KT AT TIMES.
CLIMATE
ISSUED AT 307 AM CDT TUE APR 14 2026
RECORD HIGHS FOR 4/14:
PEORIA: 86 (2024)
SPRINGFIELD: 89 (2006)
LINCOLN: 87 (2006)
NORMAL: 84 (2006)
URBANA: 84 (2010)
DECATUR: 88 (1941)
FORECAST HIGHS FOR 4/14/2026:
PEORIA: 84
SPRINGFIELD: 87
LINCOLN: 86
NORMAL: 84
URBANA: 84
DECATUR: 85
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...MJA
DISCUSSION...MJA
AVIATION...25
CLIMATE...25/MJA
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