652  
FXUS63 KLOT 131134  
AFDLOT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL  
634 AM CDT SAT JUN 13 2026  
   
KEY MESSAGES
 
 
- SCATTERED THUNDERSTORMS LATE THIS AFTERNOON THROUGH EARLY  
SUNDAY MORNING. A FEW STORMS COULD BE STRONG TO SEVERE.  
 
- POSSIBLE DANGEROUS SWIMMING CONDITIONS AT INDIANA LAKE  
MICHIGAN BEACHES SUNDAY.  
 
- COOLER TEMPERATURES EARLY NEXT WEEK WITH PRECIPITATION  
CHANCES RETURNING MIDWEEK.  
 

 
   
DISCUSSION
 
 
ISSUED AT 210 AM CDT SAT JUN 13 2026  
 
OVERALL CONFIDENCE REMAINS LOW FOR CONVECTIVE/PRECIP TRENDS  
LATER TODAY INTO TONIGHT. THIS MORNING IS EXPECTED TO BE DRY  
AREAWIDE AND THEN THERE WILL BE A LOW CHANCE (20%) FOR SHOWERS  
AND THUNDERSTORMS MAINLY ACROSS THE SOUTHERN CWA THIS AFTERNOON.  
AS A COLD FRONT APPROACHES THE AREA THIS EVENING, THAT SEEMS TO  
BE THE BEST TIME WINDOW FOR THUNDERSTORMS, LATE AFTERNOON ACROSS  
FAR NORTHWEST IL AND THEN FOR AREAS ALONG AND NORTH OF I-80  
DURING THE EVENING. SHOWERS MAY INCREASE IN COVERAGE LATER THIS  
EVENING AND INTO THE OVERNIGHT HOURS WITH PERHAPS JUST ISOLATED  
THUNDERSTORMS AT THAT TIME. THE POTENTIAL FOR A FEW STORMS TO  
BECOME STRONG TO SEVERE REMAINS WITH THE BEST TIMING IN THE LATE  
AFTERNOON INTO THE EVENING HOURS. HEAVY RAIN AND LOCALIZED  
FLOODING WOULD ALSO BE POSSIBLE WITH ANY STRONGER STORMS. END  
TIME OF THE PRECIPITATION IS ALSO SOMEWHAT UNCERTAIN, ENDING  
FROM NORTHWEST TO SOUTHEAST SUNDAY MORNING WITH SOME SHOWER  
ACTIVITY STILL POSSIBLE ALONG/SOUTHEAST OF I-57 AFTER DAYBREAK  
SUNDAY MORNING.  
 
WITH THE EXPECTATION THAT MUCH OF THE DAYLIGHT HOURS TODAY COULD  
BE DRY WITH AT LEAST SOME SUNSHINE THROUGH EARLY AFTERNOON,  
HIGH TEMPS MAY MAKE A RUN AT UPPER 80S FOR MANY AREAS TODAY AND  
NUDGED TEMPS UP SOME. SOUTHWEST WINDS WILL ALSO QUICKLY  
INCREASE AFTER SUNRISE WITH GUSTS INTO THE 30 MPH RANGE POSSIBLE  
TODAY.  
 
A COLD FRONT WILL MOVE ACROSS THE AREA EARLY SUNDAY MORNING,  
SHIFTING WINDS NORTHERLY AND BRINGING IN MUCH COOLER AIR. HIGH  
TEMPS ON SUNDAY MAY STRUGGLE TO REACH THE LOWER 70S AND LIKELY  
BE DEPENDENT ON HOW LONG CLOUD COVER PERSISTS ON SUNDAY WITH  
SOME SUNSHINE EXPECTED BY AFTERNOON. NORTH/NORTHWEST WINDS MAY  
GUST AS HIGH AS 30 MPH ON SUNDAY AND THESE STRONGER WINDS WILL  
ALLOW WAVES TO BUILD ACROSS SOUTHERN LAKE MICHIGAN, LEADING TO  
DANGEROUS SWIMMING CONDITIONS AT LAKE MICHIGAN BEACHES IN  
INDIANA AND POSSIBLY SOME OF THE ILLINOIS BEACHES DEPENDING ON  
THE EXACT WIND DIRECTION.  
 
NO SIGNIFICANT CHANGES IN THE MODELS FOR THE PATTERN NEXT WEEK.  
AN UPPER TROUGH IS EXPECTED TO MOVE ACROSS THE GREAT LAKES  
REGION MIDWEEK BRINGING INCREASING PRECIPITATION CHANCES BY  
WEDNESDAY AND WEDNESDAY NIGHT AHEAD OF ANOTHER COLD FRONT WHICH  
MAY BRING ANOTHER SHORT BURST OF COOLER AIR FOR THE END OF THE  
WEEK. CMS  
 

 
   
AVIATION /12Z TAFS THROUGH 18Z SUNDAY/
 
 
ISSUED AT 634 AM CDT SAT JUN 13 2026  
 
FORECAST CONCERNS INCLUDE...  
 
CHANCE OF THUNDERSTORMS LATE THIS AFTERNOON INTO THIS EVENING.  
GUSTY SOUTHWEST WINDS TODAY AND GUSTY NORTHWEST WINDS SUNDAY.  
WIND SHIFT TO NORTH/NORTHWEST EARLY SUNDAY MORNING.  
POSSIBLE MVFR CIGS TONIGHT INTO SUNDAY MORNING.  
 
PREVIOUS FORECAST REMAINS ON TRACK WITH NO SIGNIFICANT CHANGES  
WITH THIS 12Z FORECAST. WHILE THERE REMAINS UNCERTAINTY FOR  
SHOWER AND THUNDERSTORM COVERAGE AND TIMING LATER THIS AFTERNOON  
INTO TONIGHT, LATEST GUIDANCE SUPPORTS BEST TIMING FOR THUNDER  
DURING THE EVENING HOURS, WHICH IS COVERED WITH PROB THUNDER  
MENTION IN THE FORECAST. SHOWERS MAY CONTINUE INTO THE LATE  
EVENING AND OVERNIGHT AND SOME PROB OR TEMPO MENTION MAY BE  
NEEDED WITH LATER FORECASTS.  
 
SOUTHWEST WINDS WILL STEADILY INCREASE THROUGH MID MORNING WITH  
GUSTS INTO THE MID 20KT RANGE EXPECTED THROUGH EARLY EVENING.  
WINDS WILL SLOWLY TURN WESTERLY THIS EVENING, THEN SHIFT TO THE  
NORTH/NORTHWEST AS A COLD FRONT MOVES ACROSS THE AREA EARLY  
SUNDAY MORNING. THESE NORTH/NORTHWEST WINDS MAY GUST INTO THE  
20KT RANGE SUNDAY MORNING.  
 
MVFR CIGS WILL BE POSSIBLE TONIGHT INTO SUNDAY MORNING AND WILL  
BE DEPENDENT ON THE PRECIPITATION COVERAGE WITH PERHAPS THE BEST  
CHANCE FOR MVFR CIGS ALONG AND BEHIND THE COLD FRONT. MOST  
RECENT GUIDANCE SUGGESTS ANY MVFR CIGS WILL BE BRIEF AND OPTED  
TO MAINTAIN SCATTERED MENTION FOR NOW. CMS  
 

 
   
LOT WATCHES/WARNINGS/ADVISORIES
 
 
IL...NONE.  
IN...NONE.  
LM...NONE.  
 

 
 

 
 
VISIT US AT WEATHER.GOV/CHICAGO  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab IL Page
The Nexlab IN Page Main Text Page