573
FXUS63 KILX 280508
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
1208 AM CDT TUE JUL 28 2026
KEY MESSAGES
- IN THE WAKE OF THE PASSAGE OF A COLD FRONT OVERNIGHT, DRIER
AIR WILL SLOWLY FILTER INTO THE REGION ON TUESDAY, WITH MORE
SUBSTANTIAL LOWER DEW POINTS ARRIVING TUESDAY NIGHT.
DISCUSSION
ISSUED AT 218 PM CDT MON JUL 27 2026
OUTSIDE OF THE STORM RISK TODAY, IT HAS BEEN VERY HOT AND HUMID
TODAY. HEAT INDICES HAVE BEEN AROUND 100-105 SO FAR BUT STILL HAVE
TIME TO INCREASE TO ABOUT 115 DEGREES IN SOME SPOTS. THE EXTREME
HEAT WARNING CONTINUES UNTIL TONIGHT AT 9 PM. IF THUNDERSTORMS
MATERIALIZE AND MOVE IN DURING THE AFTERNOON AND EARLY EVENING, IT
WOULD COOL TEMPS/HEAT INDICES AND WOULD LIKELY END THE HEAT
HEADLINES EARLIER THAN 9 PM. BEYOND TODAY, TEMPERATURES BECOME MORE
SEASONABLE AND LESS HUMID WITH HIGHS IN THE 80S AND LOWS IN THE 60S
THROUGH NEXT WEEK.
TODAY'S FORECAST HAS BEEN A DOOZY. THE MODELS HAVEN'T BEEN OF THE
GREATEST ASSISTANCE RECENTLY WITH THIS ROUND OF CONVECTION. WE HAVE
AN ENHANCED RISK (LEVEL 3 OF 5) FOR AREAS NEAR AND NORTH OF A HENRY
TO MARSHALL LINE AND A SLIGHT RISK (LEVEL 2 OF 5) ELSEWHERE FOR
TODAY. PRIMARILY THIS RISK IS FOR DAMAGING WINDS, POTENTIALLY
STRONGER THAN 70 MPH, BUT THERE IS ALSO A 2% TORNADO RISK FOR THE
AREA WITHIN THE ENHANCED RISK.
OUR 12Z SOUNDING SHOWS MUCAPE OVER 5500 J/KG, EFFECTIVE SHEAR OF ~50
KNOTS, AND PWATS OF NEARLY 2 INCHES. A SHORTWAVE IS PULSING THROUGH
THIS AFTERNOON ACROSS ILLINOIS AND INDIANA, BASED OFF GFS 500 MB
VORTICITY. THE STORMS CURRENTLY OVER THE CHICAGO-LAND AREA MAY CLIP
EASTERN IL AS IT DROPS SOUTH INTO INDIANA AND THEY ARE EVOLVING INTO
A DAMAGING WIND THREAT AS IT TRANSITIONS TO A LINEAR MODE RATHER
THAN SUPERCELLULAR. IT IS STARTING TO TREND TOWARDS AREAS WEST OF I-
55 MAY NOT SEE ANY OF THE SEVERE THREAT TODAY. THERE MAY BE SOME
SHOWERS/STORMS THAT DIRECTION BUT IT LOOKS LIKE THE MAIN SHOW WILL
REMAIN EAST OF I-55 THIS AFTERNOON/EVENING. AN ADDITIONAL WAVE MAY
MOVE BEHIND IT THAT WILL ALSO DROP SOUTH, POTENTIALLY RIDING THE
IL/IN BORDER, BUT COULD POSSIBLY BE WEAKER IN STRENGTH, BASED OFF
THE HRRR. THE HRRR'S 16Z AND 17Z RUNS ARE PICKING UP THE ACTIVE
CONVECTION WELL. THE STORMS SHOULD HAVE EXITED BY 10 PM TONIGHT.
STORMS WILL BE MOVING TO THE SOUTH-SOUTHEAST AT 30-40 MPH THIS
AFTERNOON/EVENING.
THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS COMES IN ON FRIDAY
INTO SATURDAY AS A SHORTWAVE MOVES THROUGH THE AREA.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1208 AM CDT TUE JUL 28 2026
COLD FRONT IS DROPPING SOUTHWARD AND WILL SWITCH WINDS AROUND TO
THE NORTHWEST OVER THE NEXT FEW HOURS, BEFORE BECOMING MORE
NORTH-NORTHEAST TOWARD 12Z. MAIN AVIATION CONCERN IS WITH MVFR
CEILINGS DEVELOPING UPSTREAM, PUSHING TOWARD THE SOUTHWEST. HREF
CEILING PROBABILITIES SUGGEST KBMI/KCMI ARE MOST AT RISK OF THE
LOWER CEILINGS, AND WILL START OFF THE NEW TAF SET WITH TEMPO
MENTIONS AT THESE SITES UNTIL THE EXTEND OF THE LOWER CLOUD
SHIELD BECOMES MORE APPARENT.
ILX WATCHES/WARNINGS/ADVISORIES
NONE.
KEY MESSAGES...GEELHART
DISCUSSION...COPPLE
AVIATION...GEELHART
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