588
FXUS63 KILX 031755
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1255 PM CDT SUN MAY 3 2026
KEY MESSAGES
- A COUPLE THUNDERSTORMS ARE FORECAST OVER PARTS OF CENTRAL AND
SOUTHEAST ILLINOIS THIS EVENING INTO TONIGHT, WITH THE HIGHEST
CHANCES (30-50%) SOUTH OF A JACKSONVILLE TO ROBINSON LINE.
MORE NUMEROUS STORMS ARE FORECAST TOMORROW EVENING INTO EARLY
TUESDAY MORNING.
- EACH ROUND OF STORMS WILL CARRY A LEVEL 1 OF 5 (MARGINAL)
RISK FOR SEVERE WEATHER, WITH LOCALLY LARGE HAIL AND DAMAGING
WIND GUSTS THE PRIMARY HAZARDS.
DISCUSSION
ISSUED AT 150 AM CDT SUN MAY 3 2026
*** AM SHOWERS, TURNING BREEZY, FEW STORMS LATE TODAY ***
AT 145AM, RAP MESOANALYSIS REVEALS A POSITIVELY-TILTED MID-LEVEL
TROUGH EXTENDING FROM THE UPPER MIDWEST SOUTHWESTWARD INTO THE
CENTRAL HIGH PLAINS. CLOUD COVER AND A FEW LIGHT SHOWERS ARE
ACCOMPANYING THIS FEATURE UPSTREAM ACROSS MINNESOTA AND WISCONSIN,
AND CAMS SUGGEST THESE WILL SHIFT OVER THE LOCAL AREA BY MID
MORNING. THE 00Z RAOB IS QUITE DRY (PW OF 0.29"), SO WE SUSPECT MOST
OF THIS RAIN WON'T REACH THE SURFACE; NONETHELESS, WITH CAMS
SUGGESTING THE HEAVIEST SHOWERS WILL DROP A COUPLE HUNDREDTHS OF
RAINFALL WE FELT 15-30% POPS WERE WARRANTED. SHORTLY AFTER THIS
ACTIVITY WILL BE A PERIOD OF GUSTY SOUTHWEST WINDS AS THE GRADIENT
TIGHTENS BETWEEN THE APPROACHING SURFACE LOW AND DEPARTING HIGH
PRESSURE. BUFKIT SOUNDINGS SUGGEST SUSTAINED SPEEDS AND GUSTS MAY
BRIEFLY APPROACH 25 AND 40 MPH, RESPECTIVELY, ESPECIALLY BETWEEN THE
IL RIVER VALLEY AND I-57 DURING THE 1-4PM TIMEFRAME.
THIS PUSH OF WARM AIR ADVECTION (WAA) WILL BRING AFTERNOON
TEMPERATURES INTO THE LOW 70S WEST OF ROUGHLY I-55, WHILE AFTERNOON
HIGHS RUN A BIT COOLER (MID TO UPPER 60S) EAST OF THE I-57 CORRIDOR.
DURING THE EVENING, A MID LEVEL DISTURBANCE WILL COOL TEMPERATURES
ALOFT AND RESULT IN 500-1000 J/KG ELEVATED MUCAPE ROOTED AROUND THE
800MB LEVEL WHILE PROVIDING LIFT TO TRIGGER A COUPLE THUNDERSTORMS.
SUSTAINED WITH A STEADY SUPPLY OF MOISTURE VIA A 40-50 KT LLJ, AND
GIVEN 45-55 KT DEEP-LAYER SHEAR, THESE STORMS MAY BECOME STRONG
ENOUGH TO SUPPORT LOCALLY SEVERE HAIL WITH A LOWER BUT NONZERO WIND
RISK AS WELL. MODELS HAVEN'T FULLY AGREED ON WHERE THEY'LL SET UP,
BUT NEIGHBORHOOD PROBABILITIES FOR >40 DBZ REFLECTIVITY FROM THE
HIGH RESOLUTION ENSEMBLE FORECAST (HREF) SYSTEM SUGGEST THE HIGHEST
CONFIDENCE (30-50%) WILL BE ACROSS AREAS NEAR AND SOUTH OF A ROUGHLY
JACKSONVILLE TO ROBINSON LINE FROM 7PM TO 1AM.
*** CONTINUED STORM CHANCES MONDAY THROUGH TUESDAY NIGHT ***
THOUGH IT WON'T BE QUITE AS BREEZY AS TODAY, WAA WILL CONTINUE
TOMORROW, AND SINCE THE DAY WILL START ABOUT 10 DEGREES WARMER WE
SUSPECT THE HRRR AND RAP ARE REASONABLE IN DEPICTING AFTERNOON HIGHS
IN THE UPPER 70S TO LOW 80S. INSTABILITY IS FORECAST TO BUILD DURING
THE DAY WITH HREF AND REFS (RAPID ENSEMBLE FORECAST SYSTEM) MEAN
SHOWING OVER 1000 J/KG SBCAPE BY LATE AFTERNOON. LACK OF FORCING AND
A WEAK CAPPING INVERSION SHOULD FOSTER DRY CONDITIONS UNTIL MOISTURE
CONVERGENCE ON THE NOSE OF THE LLJ SPARKS SCATTERED SHOWERS AND
STORMS DURING THE EVENING. GUSTY TO LOCALLY SEVERE (58+ MPH) WINDS
MAY ACCOMPANY THE STRONGEST STORMS, PARTICULARLY IN ANY BOWING
LINEAR SEGMENTS, THOUGH WE CAN'T FULLY RULE OUT AN INSTANCE OF
SEVERE (1"+) HAIL. THE RISK WOULD APPEAR HIGHEST NORTH OF ROUGHLY I-
72/DANVILLE DURING THE 7PM TO MIDNIGHT TIMEFRAME, THOUGH SOME RISK
MAY EXTEND AS FAR SOUTH AS I-70 - ROUGHLY THE SOUTHERN BOUND OF
SPC'S LEVEL 1 OF 5 (MARGINAL) RISK.
A COLD FRONT WILL SINK SOUTHWARD ACROSS THE AREA TOMORROW NIGHT,
STALLING OVER SOUTHERN ILLINOIS AND SERVING AS A FOCUS FOR
ADDITIONAL WAVES OF SHOWERS AND A FEW THUNDERSTORMS THROUGH AT LEAST
TUESDAY NIGHT. IN FACT, TUESDAY IS SETTING UP TO BE QUITE THE DAMP
AND GLOOMY DAY WITH CLOUD COVER, NEARLY CONTINUOUS SHOWERS, AND
TEMPERATURES IN THE 50S. THE NATIONAL BLEND OF MODELS (NBM) EVEN
SUGGESTS THERE WILL BE A 40-60% (5-15%) CHANCE FOR MORE THAN AN INCH
(2 INCHES) OF RAINFALL SOUTH OF ROUGHLY THE I-72 CORRIDOR. IN THEORY
THIS SHOULDN'T FALL FAST ENOUGH TO RESULT IN HYDROLOGICAL ISSUES,
BUT GIVEN HOW MUCH RAIN (UP TO 5 INCHES) SOME OF THESE AREAS
RECEIVED LAST WEEK WE WILL NEED TO KEEP ONE EYE ON THIS.
*** STAYING COOL WITH LOW PRECIP CHANCES LATE WEEK ***
THE PARENT UPPER LEVEL TROUGH WILL LINGER OVER ONTARIO LATE WEEK,
WITH SHORTWAVES ORBITING IT AND OFFERING THE LOCAL AREA WITH
PERIODIC, LOW (15-30%) SHOWER CHANCES AND SHOTS OF CHILLY CANADIAN
AIR THROUGH THE EARLY PART OF THE WEEKEND. WHILE GLOBAL MODELS AND
THEIR RESPECTIVE ENSEMBLES DIFFER IN HOW LONG IT WILL TAKE FOR THIS
UPPER LEVEL TROUGH TO RETREAT TO THE NORTHEAST, NBM'S
PROBABILISTIC DISTRIBUTION FOR DAILY HIGH TEMPERATURES SHIFTS
UP EACH DAY THURSDAY THROUGH SATURDAY. FOR EXAMPLE, THE 10TH
PERCENTILE (90% CHANCE OF WARMER TEMPERATURES) IN LINCOLN
INCREASES FROM 56 THURSDAY TO 61 FRIDAY TO 66 SATURDAY.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1255 PM CDT SUN MAY 3 2026
SCATTERED TSRA POSSIBLE THIS EVENING AND OVERNIGHT MAINLY SOUTH
OF I-72, BUT COULD AFFECT KSPI-KDEC-KCMI. AT THIS POINT,
PROBABILITIES OF OCCURRENCE ARE TOO LOW FOR MENTION IN KCMI
TAF, BUT HAVE PROB30 FOR KSPI/KDEC. STRONGEST STORMS WOULD
MAINLY BE KSPI SOUTHWESTWARD SO HAVE NOT INCORPORATED MVFR
MENTION AT KDEC, BUT ANY STRONGER STORMS COULD CREATE MVFR
CONDITIONS AS WELL AS STRONG GUSTY WINDS. LOW CHANCES FOR
ISOLATED TSRA POSSIBLE AGAIN AFTER 18Z. WINDS SW 18-22 KTS WITH
GUSTS AROUND 30 KTS, DECREASING AFTER 21Z AND BECOMING SW UNDER
10 KTS BY 03Z. SW WINDS INCREASING TO 10-20 KTS WITH GUSTS 20-30
KTS BY 16Z MONDAY.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...BUMGARDNER
DISCUSSION...BUMGARDNER
AVIATION...37
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