219  
FXUS63 KIWX 181835  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
235 PM EDT THU JUL 18 2019  
   
SYNOPSIS
 
 
ISSUED AT 235 PM EDT THU JUL 18 2019  
 
AREAS OF RAIN AND THUNDERSTORMS THIS AFTERNOON WILL GIVE WAY TO  
MAINLY DRY CONDITIONS TONIGHT THROUGH SATURDAY MORNING. CHANCES  
FOR SHOWERS AND THUNDERSTORMS RETURN SATURDAY AFTERNOON THROUGH  
SUNDAY. HOT AND HUMID OTHERWISE ON FRIDAY AND SATURDAY AS HIGHS  
REACH THE 90S AND PEAK AFTERNOON HEAT INDICES REACH TO BETWEEN 100  
AND 100 DEGREES. THIS WILL BE FOLLOWED BY A PERIOD OF COOLER AND  
LESS HUMID WEATHER CONDITIONS NEXT WEEK.  
 

 
   
SHORT TERM
 
(THIS AFTERNOON THROUGH SATURDAY)  
ISSUED AT 235 PM EDT THU JUL 18 2019  
 
CLUSTERS OF SHOWERS/STORMS ASSOCIATED WITH A CONVECTIVELY ENHANCED  
WAVE AND WARM ADVECTION SURGE SHOULD EXIT EAST BY LATE THIS  
AFTERNOON. AN ISOLATED STRONG STORM WILL BE POSSIBLE. ESTABLISHED  
COLD POOL WITH THIS ACTIVITY REALLY PUT ON DAMPER ON HEAT/HUMIDITY  
TODAY, MAINLY ALONG/NORTHWEST OF US 24. SOME LATE DAY RECOVER IS  
EXPECTED HERE BUT LIKELY NOT ENOUGH FOR HEADLINE LEVEL APPARENT T  
VALUES. PUSHED BACK THE EXCESSIVE HEAT WARMING TO FRIDAY ACROSS  
NORTHERN ZONES AS A RESULT...AND MAY NEED TO DO SOMETHING SIMILAR  
IN OUR SOUTHERN ZONES.  
 
EXCESSIVE HEAT WILL FINALLY BE THE MAIN STORY THEN INTO FRIDAY  
AND SATURDAY AS SUBTROPICAL RIDGE BUILDS NORTH (592 DAM HEIGHTS AT  
500 MB) AND BAROCLINIC WESTERLIES SHIFT FARTHER NORTH TOWARD THE  
US/CANADA BORDER. THE MAIN/ACTIVE FRONTAL ZONE ON THE SOUTHERN  
FRINGE OF THESE ZONAL WESTERLIES WILL SET UP FROM THE UPPER  
MIDWEST EAST INTO THE CENTRAL/NORTHERN GREAT LAKES DURING THIS  
TIME. THIS SHOULD ALLOW A PLAINS EML CAP TO BUILD IN LOCALLY WITH  
CONVECTIVE COMPLEXES FOCUSED NORTH AND NORTHWEST OF THE IWX CWA.  
WITH THAT SAID, CANNOT COMPLETELY RULE OUT CONVECTION (10-30%  
POPS) LATER TONIGHT-FRIDAY IN LOWER MI/FAR NW OH, AND AGAIN  
SATURDAY AFTERNOON ACROSS THE ENTIRE AREA, AS OUTFLOW BOUNDARIES  
POSSIBLY SURVIVE INTO THIS INCREASINGLY UNSTABLE/HUMID AIRMASS.  
OVERALL EXPECTATIONS ARE FOR MAINLY DRY CONDITIONS TONIGHT THROUGH  
SATURDAY, WITH HEAT AND HUMIDITY THE MAIN CONCERN.  
 

 
   
LONG TERM
 
(SATURDAY NIGHT THROUGH THURSDAY)  
ISSUED AT 235 PM EDT THU JUL 18 2019  
 
FRONTAL BOUNDARY AND/OR COMPOSITE OUTFLOW WILL SINK SLOWLY SOUTH  
THROUGH THE AREA SATURDAY NIGHT INTO SUNDAY WITH PERIODIC CHANCES  
FOR SHOWERS/STORMS. LOCALLY HEAVY RAINFALL AND ISOLATED  
STRONG/SEVERE STORMS APPEAR BE THE PRIMARY THREATS. MAINLY DRY  
WEATHER, MUCH LOWER HUMIDITY LEVELS, AND TEMPS NEAR TO SLIGHTLY  
BELOW NORMAL WILL FOLLOW THIS FRONTAL PASSAGE FOR MUCH OF NEXT  
WEEK.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 120 PM EDT THU JUL 18 2019  
 
CONVECTION WILL KEEP CONFIDENCE LOW FOR THE 18Z TAF CYCLE. PRIMARY  
LINE OF CONVECTION HAS JUST MOVED THROUGH THE KFWA TERMINAL WHILE  
GENERAL SHOWERS ARE PREVAILING AT KSBN. HAVE HELD ONTO TEMPO GROUP  
FOR KFWA WHILE KEEPING SHOWERS PREVAILING AT KSBN FOR THE FIRST  
FEW HOURS. IN GENERAL A BROAD AREA OF CONVECTION WILL SLOWLY  
PROGRESS TO THE EAST THROUGH 21Z. HAVE THEN GONE WITH A GENERAL  
IMPROVING TREND WITH VFR CONDITIONS THROUGH THE OVERNIGHT HOURS.  
GUSTY WINDS ARE POSSIBLE.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR INZ009-017-  
018-020-022>027-032>034.  
 
EXCESSIVE HEAT WARNING FROM 8 AM EDT /7 AM CDT/ FRIDAY TO 8 PM  
EDT /7 PM CDT/ SATURDAY FOR INZ003>008-012>016.  
 
MI...EXCESSIVE HEAT WARNING FROM 8 AM FRIDAY TO 8 PM EDT SATURDAY FOR  
MIZ077>081.  
 
OH...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR OHZ001-002-  
004-005-015-016-024-025.  
 
LM...NONE.  

 
 

 
 
SYNOPSIS...STEINWEDEL  
SHORT TERM...STEINWEDEL  
LONG TERM...STEINWEDEL  
AVIATION...CM  
 
VISIT US AT WWW.WEATHER.GOV/IWX  
 
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:  
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA  
WWW.TWITTER.COM/NWSIWX  
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA  
 
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