456  
FXUS63 KIWX 270724  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
324 AM EDT FRI JUN 27 2025  
   
KEY MESSAGES  
 
- HEAT ADVISORY THIS AFTERNOON FOR HEAT INDICES APPROACHING 100  
DEGREES. AFTERNOON CONVECTION AND CLOUDS COULD LIMIT OVERALL  
DURATION OF IMPACTS.  
 
- SCATTERED (40 TO 50%) SHOWERS AND STORMS THIS AFTERNOON AND  
EVENING WITH LOCALLY GUSTY WINDS AND VERY HEAVY RAINFALL  
EXPECTED. SOMEWHAT BETTER CHANCES FOR SHOWERS AND STORMS  
MONDAY AFTERNOON/EVENING (60 TO 70%)  
 
- MORE SEASONABLE TEMPERATURES AND LOWER HUMIDITY VALUES  
EXPECTED TUESDAY AND BEYOND.  
 
 
   
DISCUSSION  
 
ISSUED AT 321 AM EDT FRI JUN 27 2025  
 
SHOWERS/STORMS CONTINUE TO PERCOLATE IN W/NW AREAS ON THE EDGE OF A  
HIGHER CAPE GRADIENT WITH AN UNCAPPED ATMOSPHERE AND MULTIPLE  
OUTFLOW BOUNDARIES ALLOWING FOR RE-DEVELOPMENT. OVERALL TRENDS  
CONTINUE HEADING SLOWLY DOWN, BUT CAN'T COMPLETELY RULE OUT A FEW  
SHOWERS POPPING HERE AND THERE THE REMAINDER OF THE NIGHT.  
 
WHILE THE FORECAST AREA WILL REMAIN ON THE EDGE OF THE SPRAWLING  
UPPER LEVEL RIDGE, SOME MODEST LOWERING OF HEIGHTS WILL TAKE PLACE  
IN RESPONSE TO A WEAK TROUGH THAT PASSES JUST TO OUR NORTH. AT THE  
SURFACE A "COOL FRONT" WILL MAKE ITS WAY ACROSS THE AREA DURING PEAK  
HEATING, INTERACTING WITH AN ATMOSPHERE THAT IS RELATIVELY UNCHANGED  
(1000-2000 J/KG OF MLCAPE, OVERALL SHEAR AOB 25 KTS AND MODEST LAPSE  
RATES) TO RESULT IN YET ANOTHER DAY OF PULSE TYPE STORMS INITIATING  
IN NW AREAS BETWEEN 18 AND 21Z AND THEN PROGRESSING SE. REMNANT  
OUTFLOW BOUNDARIES COULD ALLOW FOR EARLIER DEVELOPMENT IN SOME  
AREAS. WHILE THE GREATEST THREAT WILL BE LOCALLY HEAVY RAIN,  
STRONGER STORMS THAT CAN ATTAIN SUFFICIENT HEIGHTS DUE TO  
BOUNDARY AND STORM INTERACTIONS COULD PRODUCE POCKETS OF 50 TO  
LOCALLY AS HIGH AS 65 MPH WIND GUSTS. SPC MAINTAINED THE  
MARGINAL RISK (LEVEL 1 OF 5) WITH A SLIGHT RISK INTRODUCED JUST  
NE OF OUR AREA CLOSER TO SLIGHTLY BETTER SHEAR.  
 
THE ANTICIPATED CONVECTION RESULTED IN A LOT OF DISCUSSION ON  
HOW HIGH HEAT INDICES CAN GET AGAIN THIS AFTERNOON. EVEN WITH  
POCKETS OF STORMS THE PAST COUPLE OF DAYS, HEAT INDICES HAVE  
MANAGED TO REACH EITHER SIDE OF 100 DEGREES IN MANY AREAS. SOME  
MID/HIGH CLOUDS MAY EXIST THIS MORNING IN THE WEST, BUT WITH  
TEMPERATURES STARTING IN THE LOW TO MID 70S IT WON'T TAKE LONG  
TO WARM WELL INTO THE 80S TO NEAR 90 (ESPECIALLY SE AREAS). MUCH  
DISCUSSION TOOK PLACE IN HOUSE AND WITH OTHER OFFICES AND WHILE  
TRUE "HEAT ADVISORY" CRITERIA MAY FALL SHORT IN FINAL VALUES OR  
DURATION, GIVEN ABOVE NOTED CONCERNS HAVE OPTED TO ISSUE ONE  
MORE HEAT ADVISORY FOR THE ENTIRE AREA GIVEN THE LONGEVITY OF  
THIS OVERALL HEAT WAVE.  
 
THE FRONT WILL SAG SOUTH TONIGHT INTO SATURDAY AS THE UPPER TROUGH  
SHIFTS EAST BRINGING SOMEWHAT COOLER AND LESS HUMID CONDITIONS. THE  
RIDGE WILL EDGE BACK NORTH SUNDAY INTO EARLY MONDAY WITH  
TEMPERATURES MAKING ONE MORE RUN AT THE UPPER 80S TO AROUND 90.  
DEWPOINTS MAY REMAIN JUST LOW ENOUGH TO KEEP HEADLINES AT BAY, BUT  
LATER SHIFTS CAN SORT THAT OUT. A SOMEWHAT MORE PRONOUNCED TROUGH  
AND FRONT WILL FINALLY SEND TEMPERATURES BACK INTO THE 80S AND MOST  
NOTICEABLE LOWER HUMIDITY VALUES TO SOMEWHAT MORE TYPICAL  
LEVELS. SCATTERED TO NUMEROUS SHOWERS/STORMS ARE EXPECTED MONDAY  
AFTERNOON AND EVENING WITH A LOW LIKIHOOD OF SEVERE WEATHER AT  
THIS TIME.  
 
TUESDAY THROUGH THURSDAY LOOK TO BE GENERALLY RAIN FREE AND PLEASANT  
BEFORE A WARM FRONT BEGINS TO EDGE NORTH WITH SLGT CHC TO CHC POPS  
AT TIMES.  
 
 
   
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/  
 
ISSUED AT 113 AM EDT FRI JUN 27 2025  
 
THUNDERSTORMS CONTINUE TO PERCOLATE OVER NORTHWEST IN, IMPACTING  
KSBN. NUMEROUS OUTFLOW BOUNDARIES ARE NOTED AND THIS ACTIVITY IS  
ROOTED NOT ONLY ON THOSE OUTFLOWS BUT ON A MOISTURE GRADIENT  
ALOFT PER MID-LEVEL WATER VAPOR IMAGERY. THIS ACTIVITY OUGHT TO  
DECLINE IN COVERAGE ANY HOUR NOW WITH A LOSS OF DAYTIME HEATING  
AND EVENTUALLY A WORKED OVER ATMOSPHERE. STORMS ARE NOT EXPECTED  
TO ARRIVE TO KFWA AS THEY ARE MOVING NE.  
 
AS LOW PRESSURE MOVES THROUGH MI TODAY, WIND WILL BE ON THE  
INCREASE FOLLOWED BY A CHANCE FOR THUNDERSTORMS AHEAD OF A COLD  
FRONT. I DID ADJUSTED THE ONSET TIME OF STORMS LATER AT KSBN  
WHERE THERE IS SOME QUESTION AS TO WHETHER STORMS MAY FIRE EAST  
OF KSBN. HIGHER CONFIDENCE IN A TSRA AT KFWA DURING THE DAYTIME  
HOURS.  
 
 
   
IWX WATCHES/WARNINGS/ADVISORIES  
 
IN...HEAT ADVISORY FROM NOON EDT /11 AM CDT/ TODAY TO 8 PM EDT /7  
PM CDT/ THIS EVENING FOR INZ005>009-012>015-017-018-020-  
022>027-032>034-103-104-116-203-204-216.  
OH...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR  
OHZ001-002-004-005-015-016-024-025.  
MI...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR  
MIZ078>081-177-277.  
MARINE...NONE.  
 
 
 
 
 
DISCUSSION...FISHER  
AVIATION...BROWN  
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