488
FXUS63 KILX 160910
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
410 AM CDT THU JUL 16 2026
KEY MESSAGES
- SEASONABLY WARM AND HUMID WEATHER CONTINUES THROUGH SATURDAY
WITH MAXIMUM AFTERNOON HEAT INDICES AROUND 100 DEGREES, GIVE
OR TAKE A FEW DEGREES.
- SHOWER AND THUNDERSTORM CHANCES RETURN THIS AFTERNOON THROUGH
SATURDAY EVENING. THERE IS A MARGINAL RISK OF SEVERE STORMS
FROM MID TO LATE SATURDAY AFTERNOON INTO THE EVENING FOR
MAINLY DAMAGING WINDS. THERE IS ALSO A MARGINAL RISK OF
EXCESSIVE RAINFALL IN SOUTHEAST IL THIS AFTERNOON AND OVER
EASTERN IL ON FRIDAY.
DISCUSSION
ISSUED AT 355 AM CDT THU JUL 16 2026
PATCHY SHALLOW GROUND FOG WAS BEGINNING TO DEVELOP OVER PARTS OF
CENTRAL IL ESPECIALLY NEAR RIVER VALLEYS AND RURAL CORNFIELDS.
HRRR, RAP13 AND GFSLAMP SHOW PATCHY FOG AND LOCALLY DENSE IN
SPOTS THROUGH 12Z ESPECIALLY OVER WABASH AND IL RIVER VALLEYS
AND FROM LINCOLN AND SPI EASTWARD AND DISSIPATE BETWEEN 12-13Z.
A 593-594 DECAMETER 500 MB HIGH PRESSURE RIDGE REMAINS NEAR IL
TODAY THOUGH WE ARE SEEING A FEW WEAK FORCING MECHANISMS AT
PLAY THIS AFTERNOON OVER PARTS OF CENTRAL/SE IL. A WEAKENING
COLD FRONT OVER NE IL TO APPROACH FAR NE CWA DURING THIS MORNING
BEFORE RETREATING BACK TO THE NE THIS AFTERNOON. ITS ISOLATED
TO SCATTERED CONVECTION THIS AFTERNOON TO BE NE OF CWA.
MEANWHILE A WEAK DISTURBANCE OVER THE MID MS RIVER VALLEY HAS
DEEPER TROPICAL MOISTURE PUSHING NORTHWARD OVER CENTRAL AND
ESPECIALLY SOUTHEAST IL THIS AFTERNOON. CAMS SHOWS ISOLATED TO
SCATTERED CONVECTION DEVELOPING DURING THIS AFTERNOON FROM SPI
TO PARIS SOUTH WITH BEST CHANCES IN SE IL WHERE WPC DAY1 ERO HAS
MARGINAL RISK OF EXCESSIVE RAINFALL. A FEW CELLS COULD ALSO
HAVE GUSTY WINDS IN SOUTHEAST IL THIS AFTERNOON ALONG WITH
POSSIBLE FUNNEL CLOUDS INTO EARLY EVENING. AIR QUALITY ALERTS
REMAIN IN EFFECT INTO THIS EVENING NORTHERN/NE IL INTO
CENTRAL/NORTHEAST INDIANA. HRRR SURFACE SMOKE FORECAST HAS IT
GETTING ABOUT AS FAR SW AS A LASALLE TO PONTIAC TO LAFAYETTE
LATER TODAY AND TONIGHT BEFORE RETREATING BACK TO THE NORTHEAST
ON FRIDAY. WE WILL LIKELY SEE SOME THIN ELEVATED SMOKE ALOFT
AROUND CIRRUS CLOUD LEVEL TODAY AND TONIGHT AND MORE PROMINENT
THE FURTHER NE YOU GO. HIGHS TODAY AROUND 90F TO LOWER 90S WITH
DEWPOINTS IN THE LOW TO MID 70S GIVING AFTERNOON HEAT INDICES IN
UPPER 90S TO LOWER 100S. MUGGY LOWS OVERNIGHT IN THE LOWER 70S.
DEEPER TROPICAL MOISTURE GETS FURTHER NORTH INTO CENTRAL IL ON
FRIDAY AND WILL SEE ISOLATED TO SCATTERED CONVECTION ESPECIALLY
FRI AFTERNOON AND BEST CHANCES EAST OF THE IL RIVER. HRRR 06Z
MODEL SHOWS LESS COVERAGE OF CONVECTION ON FRIDAY LIKELY DUE TO
WEAKER FORCING AND WORKING WITH MODERATELY UNSTABLE AIR MASS
WITH WEAK WIND SHEAR. WPC DAY2 ERO HAS MARGINAL RISK OF
EXCESSIVE RAINFALL IN EASTERN IL FRIDAY MAINLY FRI AFTERNOON.
HREF HAS LOCALIZED POCKETS OF 1.5-3 INCHES IN LESS THAN 6 HOURS
POSSIBLE IN SOUTHEAST IL THIS AFTERNOON, AND OVER AREAS EAST OF
THE IL RIVER ON FRIDAY. THOUGH MOST AREAS WILL RECEIVE MUCH
LESS RAINFALL BETWEEN A TENTH AND QUARTER INCH SOUTHERN CWA THIS
AFTERNOON, AND FROM IL RIVER EAST ON FRIDAY. HIGHS FRI IN THE
UPPER 80S TO NEAR 90F WITH AFTERNOON HEAT INDICES IN UPPER 90S
TO NEAR 100F.
A STRONGER NORTHERN STREAM SHORT WAVE MOVES INTO SOUTHERN
ONTARIO AND EASTERN GREAT LAKES LATE SATURDAY PUSHING A COLD
FRONT SOUTHWARD INTO NORTHERN IL LATE SAT AFTERNOON AND SOUTH
THROUGH CWA DURING SAT NIGHT. WILL SEE ANOTHER HOT AND HUMID
DAY AHEAD OF THIS FRONT ON SATURDAY WITH HIGHS IN THE LOWER 90S
AND AFTERNOON HEAT INDICES 100-105 AND GETTING CLOSER TO HEAT
ADVISORY CRITERIA SAT AFTERNOON. CHANCES OF CONVECTION TO
INCREASE DURING MID/LATE SAT AFTERNOON INTO SAT EVENING WITH
HIGHEST POPS IN EASTERN IL AS COLD FRONT APPROACHES LATE IN THE
DAY. SPC DAY3 OUTLOOK HAS MARGINAL RISK OF SEVERE STORMS FROM
MID TO LATE SAT AFTERNOON INTO SAT EVENING OVER CWA FOR MAINLY
DAMAGING WINDS. LOCALLY HEAVY RAINS ALSO POSSIBLE WITH PWATS
NEAR 2 INCHES.
CONVECTION CHANCES SHIFT SOUTH OF CWA LATER SAT NIGHT AND SUNDAY
WITH PASSAGE OF COLD FRONT, WITH SEASONABLE HIGHS IN MID TO
UPPER 80S SUNDAY AND A BIT LOWER DEWPOINTS IN THE UPPER
60S/LOWER 70S (HIGHEST DEWPOINTS IN SE IL AND SW CWA). SW WINDS
ON MONDAY TO BRING WARMER AND MORE HUMID AIR BACK ESPECIALLY
WEST CENTRAL/SW IL WHERE HIGHS MON IN LOWER 90S AND HEAT INDICES
MON AFTERNOON LIKELY TOP 100F. A STRONGER NORTHERN STREAM SHORT
WAVE MOVING THROUGH THE GREAT LAKES REGION MONDAY NIGHT TO PUSH
A STRONGER COLD FRONT SE THROUGH IL AND BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS. TEMPERATURES TO COOL BACK DURING MID
WEEK ESPECIALLY WED/THU WITH HIGHS IN THE LOW TO MID 80S AND
MORE COMFORTABLE DEWPOINTS IN THE LOW TO MID 60S.
THE CLIMATE PREDICTION CENTER (CPC) 6-10 DAY OUTLOOK FOR JULY
21-25 HAS 33-40% CHANCE OF BELOW NORMAL TEMPERATURES OVER
CENTRAL AND NORTHEAST IL, WITH PRECIPITATION TRENDING NEAR
NORMAL. CPC 8-14 DAY OUTLOOK FOR JULY 23-29 HAS TEMPERATURES AND
PRECIPITATION TRENDING NEAR NORMAL OVER CENTRAL AND SOUTHEAST
IL. SO HOPEFULLY WE WILL KEEP HEAT WAVES AT BAY.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1245 AM CDT THU JUL 16 2026
PATCHY SHALLOW GROUND FOG EXPECTED TO DEVELOP AGAIN DURING
OVERNIGHT AND LIFT BETWEEN 12-13Z. SPI TENDS TO BE MORE PRONE
TO THIS OCCURRENCE PAST FEW NIGHTS, SO WILL ONLY INCLUDE A
MENTION THERE AT THIS POINT WITH IFR TO MVFR CONDITIONS FROM
10-13Z. SCATTERED DIURNALLY DRIVEN CUMULUS CLOUDS WITH 3-5K FT
BASES TO APPEAR BY 15Z AND DISSIPATE AROUND DUSK/02Z. ISOLATED
TO SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP DURING MID TO
LATE AFTERNOON FROM SPI AND DEC SOUTH AND DISSIPATE AROUND
SUNSET. CONTINUED PROB30 FOR MVFR CONDTIONS WITH TSRA AT
SPI/DEC FROM 22Z-01Z. ISOLATED TO SCATTERED CONVECTION TO APPEAR
OVER NORTHEAST IL LATE THU AFTERNOON UNTIL SUNSET, BUT THIS
CONVECTION SHOULD STAY NE OF THE I-74 AIRPORTS (PIA, BMI, CMI).
ANOTHER CONCERN IS CANADIAN WILDFIRE SMOKE WHICH CURRENTLY NEAR
GROUND SMOKE AND VSBYS RESTRICTIONS SHOULD BE CONFINED TO
NORTHEAST IL, NE OF I-74 THOUGH A THIN SMOKE LAYER ALOFT AT 25K
FT COULD IMPACT THE CENTRAL IL AIRPORTS ESPECIALLY ALONG I-74.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...07
DISCUSSION...07
AVIATION...07
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