278
FXUS63 KILX 262338
AFDILX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LINCOLN IL
638 PM CDT SUN JUL 26 2026
KEY MESSAGES
- OPPRESSIVE HEAT AND HUMIDITY CONTINUE THROUGH MONDAY WITH HEAT INDICES
PEAKING BETWEEN 100 AND 110 DEGREES.
- MULTIPLE THUNDERSTORM COMPLEXES WILL MOVE ACROSS THE MIDWEST
STATES THROUGH MONDAY, PRESENTING A CONDITIONAL THREAT FOR
SEVERE WEATHER AND HEAVY RAIN.
- A COLD FRONT WILL BRING RELIEF FROM THE HEAT ON TUESDAY,
TRANSITIONING US BACK TO NEAR-NORMAL TEMPERATURES.
DISCUSSION
ISSUED AT 149 PM CDT SUN JUL 26 2026
UPPER ANALYSIS SHOWS A LARGE RIDGE OF HIGH PRESSURE OVER THE WEST-
CENTRAL US WITH NORTHWEST FLOW OVER THE MIDWEST STATES. AT THE
SURFACE, A STATIONARY/WARM FRONT IS POSITIONED FROM ROUGHLY
BURLINGTON IA TO FLORA IL. ISENTROPIC UPGLIDE ON THE ~300K SURFACE
HAS RESULTED IN A CONSISTENT LOW STRATUS DECK NEAR/EAST OF THE
BOUNDARY, ULTIMATELY HOLDING TEMPERATURES DOWN SEVERAL DEGREES LOWER
THAN ORIGINALLY ANTICIPATED. CLEARER SKIES WEST OF THE FRONT HAVE
ALLOWED TEMPERATURES TO SURGE INTO THE UPPER 80S TO LOW 90S, PAIRED
WITH DEWPOINTS IN THE LOW 80S. HEAT INDICES IN THESE SAME AREAS HAVE
CLIMBED ABOVE 100 DEGREES WITH SPRINGFIELD AND JACKSONVILLE IL
REPORTING HEAT INDICES OVER 110 DEGREES AS OF 1 PM. ALTHOUGH CLOUD
COVER LOOKS TO BE SLOW TO DEPART, ANY POCKETS OF CLEARING
SHOULD ALLOW TEMPERATURES TO QUICKLY REBOUND. BECAUSE OF THIS,
NO CHANGES TO OUR CURRENT HEAT PRODUCTS HAVE BEEN MADE.
THINGS REMAIN HOT AND HUMID ON MONDAY AS THE 850 MB RIDGE AXIS MOVES
OVERHEAD, KEEPING 22-25C 850 MB TEMPERATURES LARGELY IN PLACE.
MONDAY HAS THE POTENTIAL TO BE THE HOTTEST DAY OF THE FORECAST
PERIOD, PENDING ANY THUNDERSTORM ACTIVITY/CONVECTIVE DEBRIS
CLOUDS. MULTIPLE THUNDERSTORM COMPLEXES COULD IMPACT PARTS OF
THE REGION THROUGH MONDAY NIGHT AS SEVERAL UPPER SHORTWAVES RIDE
THE EASTERN PERIPHERY OF THE UPPER RIDGE AND A COLD FRONT
APPROACHES FROM THE NORTH. CAMS CONTINUE TO STRUGGLE WITH
THUNDERSTORM PLACEMENT AND EVOLUTION, WHICH HAS LED TO
DIFFICULTY PINPOINTING TIMING. WATER VAPOR IMAGERY SHOWS A
SUBTLE SHORTWAVE DISTURBANCE OVER EASTERN SOUTH DAKOTA/SOUTHERN
MINNESOTA WITH COMPOSITE RADAR SHOWING SOME STORMS AHEAD OF THAT
WAVE, POTENTIALLY SERVING AS OUR FIRST OPPORTUNITY FOR
CONVECTIVE ACTIVITY LATER THIS AFTERNOON OR EVENING. ADDITIONAL
WAVES ARE EXPECTED TO TRACK THROUGH THE MIDWEST STATES
OVERNIGHT INTO MONDAY AND COULD IMPACT PARTS OF THE AREA. ANY
STORMS THAT DO DEVELOP WILL HAVE THE POTENTIAL TO BECOME SEVERE
AS THEY MOVE THROUGH AN ENVIRONMENT CHARACTERIZED BY VERY STRONG
INSTABILITY (4000+ J/KG SBCAPE) AND SEASONALLY STRONG WIND
SHEAR (30- 40 KTS). HAZARDS WITH ANY SEVERE STORMS WOULD BE
DAMAGING WIND GUSTS IN EXCESS OF 60 MPH AND TORRENTIAL RAINFALL.
TEMPERATURES AND DEWPOINTS DROP CLOSER TO SEASONAL NORMALS ON
TUESDAY AS THE AIRMASS MODIFIES BEHIND A COLD FRONT. NORTHWEST FLOW
WILL REMAIN IN PLACE ALOFT THROUGH THE UPCOMING WEEK AND MAY OPEN
THE DOOR FOR SHORTWAVE DISTURBANCES THROUGH NEXT WEEKEND. A BRIEF
WINDOW OF SURFACE HIGH PRESSURE SHOULD SHIELD PRECIPITATION CHANCES
THROUGH MIDWEEK BEFORE A STRONGER UPPER WAVE APPROACHES LATER IN THE
WEEK.
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 638 PM CDT SUN JUL 26 2026
MVFR CIGS FROM KDEC-KBMI EASTWARD ARE EXPECTED TO DISSIPATE THIS
EVENING, BRINGING A PERIOD OF VFR CONDITIONS UNTIL LOWERED
VISIBILITY IN BR DEVELOPS LATE TONIGHT INTO MONDAY MORNING, FOR
MVFR OR WORSE VSBY. THUNDERSTORMS APPEAR TO BE A LOW PROBABILITY
FOR MUCH OF THE UPCOMING 24 HOURS, ALTHOUGH THERE IS POTENTIAL
FOR MOST OF THE PERIOD. THE HIGHEST CHANCES APPEAR TO BE AT KCMI
AROUND 12Z-16Z AS A FORECAST STORM COMPLEX FROM THE NORTH CLIPS
THE AREA, AND A PROB30 IS IN THE KCMI TAF. WINDS LIGHT AND
VARIABLE TO S-SW AROUND 5 KTS TONIGHT, BECOMING S 8-10 KTS AFTER
15Z.
ILX WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING UNTIL 9 PM CDT MONDAY FOR ILZ027>029-036-
037-040>042-047>052.
HEAT ADVISORY UNTIL 9 PM CDT MONDAY FOR ILZ030-031-038-043-044-
053-054-061-066-071-072.
KEY MESSAGES...NMA
DISCUSSION...NMA
AVIATION...37
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page