685  
FXUS63 KIWX 211936  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
336 PM EDT MON JUL 21 2025  
   
KEY MESSAGES
 
 
- HOT AND HUMID CONDITIONS WILL DEVELOP WEDNESDAY AND PERSIST  
THROUGH FRIDAY WITH HIGHS IN THE LOWER 90S AND HEAT INDICES  
FROM 100 TO 105.  
 
- SHOWER AND THUNDERSTORM CHANCES RETURN FOR THE UPCOMING  
WEEKEND.  
 

 
   
DISCUSSION
 
 
ISSUED AT 101 PM EDT MON JUL 21 2025  
 
PRETTY QUIET WEATHER IN THE SHORT TERM WITH NORTHWESTERLY FLOW  
ALOFT OVER THE AREA. DEW POINTS WILL ALSO BE SLIGHTLY  
DRIER THAN THE LAST COUPLE OF DAYS WITH SURFACE DEW POINT VALUES  
IN THE UPPER 50S TO MID 60S THROUGH TUESDAY. HIGH TEMPERATURES  
WILL ALSO ONLY GET INTO THE LOW TO MID 80S ACROSS THE AREA  
THROUGH TUESDAY.  
 
AS THE RETROGRADING RIDGE OVER THE SOUTHEAST MOVES WEST AND THEN  
BEGINS TO PUSH NORTHWARD INTO THE LOWER MIDWEST ON WEDNESDAY.  
THIS RIDGING MOVING INTO THE REGION WILL BRING A CAPPING  
INVERSION ALONG WITH AN INFLUX OF HOTTER TEMPERATURES AND AN  
INCREASE IN MOISTURE INTO THE AREA. BY WEDNESDAY AFTERNOON DEW  
POINTS WILL INCREASE INTO THE MID TO UPPER 70S FOR A GOOD  
PORTION OF THE AREA AND HIGH TEMPERATURES WILL WARM TO THE UPPER  
80S TO LOW 90S ESPECIALLY FOR THE WESTERN HALF OF OUR CWA. HEAT  
INDICES AROUND 100 WILL BE EXPECTED ACROSS THE WESTERN HALF OF  
THE CWA AND 90S OVER THE EASTERN PORTIONS.  
 
THURSDAY WILL SEE SLIGHTLY MORE HUMIDITY AND SLIGHTLY HOTTER  
TEMPERATURES WITH HEAT INDICES ACROSS THE ENTIRE AREA AT OR  
ABOVE 100 DEGREES. A FEW LOCATIONS MAY SEE HEAT INDICES CLOSE TO  
110, ESPECIALLY THE SOUTHERN CENTRAL PORTIONS OF THE CWA.  
 
BEGINNING LATE THURSDAY WE WILL SEE CHANCES OF SHOWERS AND  
STORMS RETURN THROUGH SATURDAY WITH DISTURBANCES MOVING ALONG  
THE SOUTHWESTERLY TO WESTERLY FLOW ALOFT AS THE RIDGE AXIS  
MOVES EASTWARD OUT OF THE AREA. THIS WILL INCREASE THE CLOUD  
COVER AND ALLOW FOR SLIGHTLY COOLER TEMPERATURES BY FRIDAY AND  
INTO THE WEEKEND. HIGHS WILL BE IN THE MID TO UPPER 80S FRIDAY  
THROUGH MONDAY. WE WILL REMAIN MOIST WITH DEW POINTS REMAINING  
IN THE 70S THROUGH MONDAY AS WELL.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
 
 
ISSUED AT 1258 PM EDT MON JUL 21 2025  
 
TRANQUIL WEATHER PERSISTS THROUGH THE TAF FORECAST PERIOD AS  
HIGH PRESSURE BUILDS INTO THE UPPER GREAT LAKES REGION. WINDS  
WILL BE LIGHT OUT OF THE EAST/SOUTHEAST AND VFR CEILINGS ARE  
EXPECTED TO CONTINUE THROUGH TOMORROW. AS SKIES CLEAR OUT  
TONIGHT AND WINDS DIMINISH, PATCHY FOG WILL ONCE AGAIN BE  
POSSIBLE. HAVE ADDED A TEMPO GROUP TO ACCOUNT FOR THIS  
POTENTIAL AT KFWA. UNSURE HOW LOW VISIBILITIES MAY DROP DOWN TO  
IF FOG DEVELOPS SO KEPT IT AT 4 MILES FOR NOW.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
OH...NONE.  
MI...NONE.  
MARINE...NONE.  
 

 
 

 
 
DISCUSSION...ANDERSEN  
AVIATION...JOHNSON  
 
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