808
FXUS63 KILX 172358
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
658 PM CDT SUN MAY 17 2026
KEY MESSAGES
- SEVERAL ROUNDS OF CONVECTION WILL IMPACT CENTRAL ILLINOIS LATE
TONIGHT THROUGH TUESDAY EVENING. WHILE ALL SEVERE WEATHER
HAZARDS WILL BE POSSIBLE, DAMAGING WIND GUSTS IN EXCESS OF
60MPH WILL BE THE MOST LIKELY.
- A BLOWING DUST ADVISORY IS POSTED UNTIL 8 PM THIS EVENING FROM
CHRISTIAN, MACON, PIATT, CHAMPAIGN AND VERMILION COUNTIES
NORTHWEST TO THE IL RIVER. SOUTHERLY WINDS GUSTING 30-40 MPH
EARLY THIS EVENING ALONG WITH A DRYING TOPSOIL FROM RECENTLY
TILLED FIELDS, COULD CAUSE BLOWING DUST WITH VISIBILITIES
RESTRICTED BETWEEN A QUARTER MILE AND ONE MILE IN SPOTS.
DISCUSSION
ISSUED AT 259 PM CDT SUN MAY 17 2026
*** ROUND ONE OF CONVECTION ***
19Z/2PM REGIONAL ANALYSIS SHOWS RAPID THUNDERSTORM DEVELOPMENT
ACROSS EASTERN SOUTH DAKOTA AHEAD OF A SHORT-WAVE TROUGH
PIVOTING NORTHEASTWARD FROM COLORADO. AS THIS WAVE INTERACTS
WITH A FRONTAL BOUNDARY DRAPED ACROSS THE PLAINS, WIDESPREAD
STRONG TO SEVERE CONVECTION WILL ORGANIZE INTO ONE OR MORE
LINEAR STRUCTURES AS IT GRADUALLY SHIFTS EASTWARD LATER THIS
EVENING INTO THE OVERNIGHT HOURS. CAMS EXHIBIT A GOOD DEAL OF
SPREAD CONCERNING BOTH THE COVERAGE AND TIMING OF THE STORMS AS
THEY CROSS THE MISSISSIPPI RIVER WELL AFTER MIDNIGHT. THE NAM IS
THE FASTEST MODEL, SHOWING CELLS POTENTIALLY ARRIVING ACROSS THE
FAR NW KILX AS EARLY AS 09Z/4AM...WHILE THE HRRR CONTINUES TO
LAG BY A COUPLE OF HOURS. REGARDLESS OF WHICH SOLUTION PANS OUT,
THE STORMS WILL BE ENTERING AN ENVIRONMENT CHARACTERIZED BY
AMPLE ELEVATED INSTABILITY, BUT WEAK DEEP-LAYER SHEAR. NAM
MUCAPES RANGE FROM 1500-2500J/KG AHEAD OF THE STORMS, WHILE
0-6KM BULK SHEAR IS JUST 25-30KT. GIVEN THE ELEVATED NATURE OF
THE CONVECTION, THINK THE PRIMARY SEVERE WEATHER RISK WILL BE
SCATTERED DAMAGING WIND GUSTS FROM THE MISSISSIPPI RIVER
EASTWARD TO THE I-55 CORRIDOR THROUGH LATE MORNING.
*** ROUND TWO OF CONVECTION ***
AS THE BROKEN LINE OF THUNDERSTORMS CROSSES I-55, IT WILL BEGIN
TO ENCOUNTER AN INCREASINGLY UNSTABLE AIRMASS ACROSS EAST-
CENTRAL AND SOUTHEAST ILLINOIS WHERE HREF MEAN SBCAPES REACH
1500-2000J/KG. ONCE THE STORMS BECOME SURFACE-BASED, ALL SEVERE
HAZARDS WILL COME INTO PLAY EAST OF I-55 MONDAY AFTERNOON,
INCLUDING DAMAGING WIND GUSTS IN EXCESS OF 60MPH, HAIL LARGER
THAN QUARTERS, AND ISOLATED TORNADOES. ALL MODEL SOLUTIONS SHOW
THE STORMS EXITING INTO THE OHIO RIVER VALLEY PRIOR TO SUNSET,
FOLLOWED BY MAINLY QUIET CONDITIONS ACROSS THE BOARD THROUGH THE
EVENING.
*** ROUND THREE OF CONVECTION ***
A SIMILAR PROCESS TO WHAT WILL HAPPEN TONIGHT WILL UNFOLD MONDAY
NIGHT AS A VIGOROUS SHORT-WAVE NOTED ON LATEST WATER VAPOR
IMAGERY OVER NEVADA ROUNDS THE BASE OF THE ROCKIES TROUGH AND
GENERATES A RENEWED ROUND OF SEVERE CONVECTION FROM OMAHA AND
DES MOINES SOUTHWESTWARD TO KANSAS CITY LATE MONDAY AFTERNOON
AND EVENING. THESE CELLS WILL ALSO GROW UPSCALE INTO A LINE OF
STORMS, THEN PROGRESS EASTWARD INTO WEST-CENTRAL ILLINOIS
OVERNIGHT. DAMAGING WIND GUSTS AND ISOLATED TORNADOES WILL BE
THE PRIMARY HAZARDS BETWEEN ABOUT 06Z/1AM AND 11Z/6AM FROM THE
MISSISSIPPI RIVER EASTWARD TO THE I-55 CORRIDOR.
*** ROUND FOUR OF CONVECTION ***
OUTFLOW FROM THE MORNING STORMS AND/OR THE APPROACHING SYNOPTIC
COLD FRONT WILL BE THE PRIMARY FOCUSING MECHANISMS FOR
ADDITIONAL STORMS TUESDAY AFTERNOON AND EVENING. WHILE THE EXACT
GENERATION ZONE IS STILL IN QUESTION, AM CONTINUING TO FOCUS
ATTENTION ON LOCATIONS EAST OF I-55 FOR THE HIGHEST PROBABILITY
OF DAMAGING WIND GUSTS, LARGE HAIL, AND A COUPLE TORNADOES.
THESE STORMS WILL DEPART INTO INDIANA BY EVENING, FOLLOWED BY A
PERIOD OF COOLER AND MUCH QUIETER WEATHER CONDITIONS TUESDAY
NIGHT THROUGH THURSDAY BEFORE THE NEXT CHANCE FOR SHOWERS
ARRIVES BY THE END OF THE WEEK.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 646 PM CDT SUN MAY 17 2026
STRONG SOUTHERLY WINDS GUSTING 25-35 KTS UNTIL SUNSET (STRONGEST
AT BMI AND CMI) WILL SUBSIDE ABOUT 5-10 KTS BETWEEN 01-02Z.
CONTINUED MENTION OF LLWS STARTING BETWEEN 03-05Z WITH 2K FT SSW
WINDS 45-50 KTS (STARTING AT PIA FIRST) AND LASTING TIL 11-13Z.
A ROUND OF SHOWERS/THUNDERSTORMS LIKELY MOVES EASTWARD INTO PIA
TOWARD DAWN BETWEEN 11-12Z, ALONG I-55 FROM 13-14Z AND DEC AND
CMI BY 15-16Z WITH MVFR CONDITIONS POSSIBLE FOR ABOUT 3-4 HOURS
WITH BAND OF CONVECTION. CONVECTION TO PUSH SE OF PIA AROUND 18Z
MON, SE OF BMI BY 20Z THOUGH SHOWERS AND ISOLATED TS ALONG I-72
TO BECOME MORE ISOLATED DURING MID/LATE MON AFTERNOON AND MAY
CONTINUE TO SEE MVFR CEILINGS POSSIBLE. BREEZY SOUTH TO SSW
WINDS CONTINUE MONDAY WITH GUSTS 22-32 KTS COMMON.
ILX WATCHES/WARNINGS/ADVISORIES
BLOWING DUST ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ILZ031-
037-038-041>053.
KEY MESSAGES...BARNES
DISCUSSION...BARNES
AVIATION...07
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