700  
FXUS63 KIWX 291027  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
627 AM EDT SAT APR 29 2017  
   
SYNOPSIS
 
 
ISSUED AT 401 AM EDT SAT APR 29 2017  
 
A WARM FRONT WILL MOVE SLOWLY NORTH FROM THE OHIO RIVER THIS  
MORNING TO SOUTHERN MICHIGAN SUNDAY CAUSING SHOWERS AND SCATTERED  
THUNDERSTORMS IN OUR AREA. HEAVY RAINFALL IS POSSIBLE, ESPECIALLY  
OVER NORTHWEST INDIANA AND SOUTHWEST MICHIGAN TONIGHT THROUGH  
SUNDAY NIGHT. COOL TEMPERATURES TONIGHT WILL WARM CONSIDERABLY  
SUNDAY BEHIND THE WARM FRONT. A COLD FRONT WILL SWEEP ACROSS THE  
AREA SUNDAY NIGHT CAUSING SHOWERS AND POSSIBLY THUNDERSTORMS.  
WINDY AND COOLER CONDITIONS WITH A CHANCE OF SHOWERS WILL FOLLOW  
THE FRONT MONDAY AND TUESDAY.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 401 AM EDT SAT APR 29 2017  
 
WARM FRONT EXTENDING NE FROM LOW OVER TX INTO TO THE OH RIVER THIS  
MORNING WITH WIDESPREAD TSTM ACTIVITY IN VCNTY OF THIS BOUNDARY.  
THIS FRONT IS EXPECTED TO LIFT SLOWLY NORTH ACROSS SRN IN TODAY  
RESULTING IN AN INCREASE IN SHOWER COVERAGE FROM SOUTH TO NORTH  
ACROSS OUR CWA. ELEVATED INSTABILITY WILL ALSO BE OVERSPREADING  
THE AREA PROVIDING CHANCE OF TSTMS TO REACH AS FAR NORTH AS THE  
TOLL ROAD. WITH THE FRONT REMAINING TO OUR SOUTH TODAY TEMPS WILL  
NOT RISE MUCH WITH HIGHS FCST TO RANGE FROM THE M50S NORTH TO THE  
M60S SOUTH. AS THE SRN PLAINS LOW LIFTS NE, WARM FRONT EXPECTED TO  
LIFT NORTH INTO CENTRAL IN TONIGHT. HEAVIEST RAINFALL EXPECTED TO  
BE ACROSS OUR NW CLOSER TO NOSE OF LLJ AHEAD OF THE EJECTING LOW.  
GIVEN VERY MOIST AIRMASS OVER-RUNNING THE FRONT AND DEEP WARM  
CLOUD LAYER, LOCALLY HEAVY RAINFALL PSBL ACROSS THE REST OF THE  
AREA, BUT STRONGER FORCING ACROSS THE NW SUPPORTS NOT EXPANDING  
THE FFA IN PLACE FOR THAT AREA ATTM. WITH WARM FRONT APCHG,  
LITTLE DIURNAL TEMP DROP EXPECTED TONIGHT WITH LOWS RANGING FROM  
THE M40S NORTH TO THE M50S SOUTH.  
 

 
   
LONG TERM
 
(SUNDAY THROUGH FRIDAY)  
ISSUED AT 401 AM EDT SAT APR 29 2017  
 
WARM FRONT EXPECTED TO LIFT INTO SRN MI SUNDAY, FOLLOWED BY A  
STRONG OCCLUDING CDFNT SWEEPING FROM SW TO NE ACROSS THE CWA  
SUNDAY NIGHT. MAIN FOCUS FOR WIDESPREAD AND POTENTIALLY HEAVY  
RAINFALL REMAINS ACROSS THE NW PORTION OF THE CWA CLOSER TO THE  
SLOW MOVING WARM FRONTAL BOUNDARY, WHILE SE SHOULD GET MORE  
SOLIDLY INTO THE WARM SECTOR SUNDAY. MODERATE INSTABILITY SHOULD  
DEVELOP IN THIS WARM SECTOR SUNDAY AFTN, BUT WK CAPPING AND LACK  
OF FORCING IN THIS AREA SUPPORTS JUST CHC TSTM POPS. TEMPS SHOULD  
WARM INTO THE 70S OVER MOST OF THE CWA SUNDAY AND IN THE L-M80S  
FAR SE.  
 
STRONG OCCLUDING COLD FRONT WILL SWEEP FROM SW TO NE ACROSS THE  
CWA SUNDAY NIGHT. DIURNAL INSTABILITY WILL BE WANING AS FRONT  
MOVES THROUGH BUT GIVEN VERY STRONG WIND FIELDS THERE COULD BE  
SOME POCKETS OF DAMAGING WIND GUSTS WITH STRONGER CONVECTIVE  
ELEMENTS ALONG THE FRONT. STRONG CAA MONDAY WILL RESULT IN STEADY  
OR SLOWLY FALLING TEMPS, MAINLY IN THE 50S WEST AND LOWER 60S  
EAST. CYCLONIC FLOW ASSOCIATED WITH SLOWLY DEPARTING DEEP LOW  
ACROSS THE UPR GRTLKS/SE CANADA MAY KEEP SOME SHOWERS IN THE AREA  
INTO TUE.  
 
MEDIUM RANGE MODELS HAVE TRENDED FARTHER NW WITH TRACK OF ANOTHER  
DEEP LOW EXPECTED MIDDLE-LATE NEXT WEEK. THIS NECESSITATED  
BUMPING UP POPS A BIT MAINLY FOR SERN PORTION OF THE CWA, THOUGH  
JUST TO CHC AS STILL QUESTIONABLE IF THIS SYSTEM WILL TRACK FAR  
ENOUGH TO THE NW TO IMPACT OUR AREA. TEMPS SHOULD REMAIN BLO  
NORMAL THROUGH THE WEEK AS UPR TROFFING BECOMES ESTABLISHED OVER  
THE ERN U.S..  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)  
ISSUED AT 622 AM EDT SAT APR 29 2017  
 
LIFR CONDITIONS HAVE SETTLED INTO KFWA AS LARGE AREA OF RAIN AND  
EMBEDDED STORMS CONTINUES TO WORK SLOWLY NORTH TOWARDS THE SITE.  
THUNDER THUS FAR HAS REMAINED JUST SOUTH OF THE SITE AND CURRENT  
TRENDS WOULD SUGGEST THIS MAY CONTINUE. HOWEVER, WILL ERR ON SIDE  
OF CAUTION AND HAVE A FEW HOURS OF VCTS. RAIN WILL EITHER SHIFT  
NORTH OR MORE LIKELY DISSIPATE THIS MORNING, POSSIBLY NOT REACHING  
KSBN. OPTIMISTIC AT LEAST SLIGHT IMPROVEMENT TO LOW END MFR/IFR  
CONDITIONS AT KFWA AS DRIER AIR WORKS IN BRIEFLY.  
 
RAIN CHANCES PERSIST THROUGH THE REMAINDER OF THE PERIOD WITH  
LITTLE OVERALL CHANGE TO PAST TAFS. HAVE KEPT VCTS FOR A PERIOD AT  
BOTH SITES WHEN INSTABILITY APPEARS BEST.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...FLASH FLOOD WATCH FROM THIS EVENING THROUGH MONDAY MORNING FOR  
INZ003-004-012.  
 
MI...FLASH FLOOD WATCH FROM THIS EVENING THROUGH MONDAY MORNING FOR  
MIZ077-078.  
 
OH...NONE.  
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT SUNDAY FOR LMZ043-046.  
 

 
 

 
 
SYNOPSIS...JT  
SHORT TERM...JT  
LONG TERM...JT  
AVIATION...FISHER  
 
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