814  
FXUS63 KIWX 212330  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
730 PM EDT SAT OCT 21 2017  
   
SYNOPSIS
 
 
ISSUED AT 722 PM EDT SAT OCT 21 2017  
 
MILD CONDITIONS WILL CONTINUE THE REST OF THIS WEEKEND BEFORE  
COOLER WEATHER ARRIVES TO START THE WORK WEEK. IT WILL REMAIN DRY  
TONIGHT WITH LOW TEMPERATURES DROPPING INTO THE 50S. HIGH  
TEMPERATURES ON SUNDAY WILL BE AROUND 75 WITH SKIES BECOMING  
CLOUDY. RAIN WILL SLOWLY SPREAD ACROSS THE AREA SUNDAY AFTERNOON  
AND SUNDAY NIGHT. MORE RAIN IS EXPECTED MONDAY INTO TUESDAY WITH  
HEAVY RAIN POSSIBLE. MUCH COOLER WEATHER IS FORECAST FOR MID WEEK  
WITH HIGHS ONLY AROUND 50 ON TUESDAY AND WEDNESDAY. EVEN COLDER  
TEMPERATURES LOOK POSSIBLE BY NEXT WEEKEND WITH A CHANCE FOR THE  
FIRST FREEZE OF THE SEASON.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH SUNDAY)  
ISSUED AT 344 PM EDT SAT OCT 21 2017  
 
SOME WEAK RETURNS OVER ILLINOIS THIS AFTERNOON WERE JUST ABLE TO  
GENERATE A HUNDREDTH OF AN INCH OF RAIN IN AN EXTREMELY DRY  
ENVIRONMENT PER MESONET SITES. MOISTURE IN THE LOWER LEVELS WILL  
BEGIN TO INCREASE TONIGHT; HOWEVER, GIVEN THE LACK OF FORCING,  
THERE IS NOT MUCH OF A CHANCE FOR MEASURABLE RAINFALL. RAIN  
CHANCES WILL BE INCREASING SUNDAY, ESPECIALLY LATER IN THE DAY  
OVER WEST AREAS INCLUDING NORTHWEST INDIANA AS A STRONG COLD FRONT  
AND UPPER LEVEL SYSTEM APPROACH. THERE IS AN OUTSIDE CHANCE FOR  
THUNDER; HOWEVER, LEFT THUNDER OUT GIVEN VIRTUALLY ZERO  
INSTABILITY.  
 

 
   
LONG TERM
 
(SUNDAY NIGHT THROUGH SATURDAY)  
ISSUED AT 344 PM EDT SAT OCT 21 2017  
 
A VERY WET PERIOD IS JUST AHEAD AS A COMBINATION OF SYSTEMS MOVES  
ACROSS THE AREA DURING THE FIRST HALF OF THIS UPCOMING WEEK. THE  
FIRST OF TWO FRONTS WILL MOVE ACROSS THE REGION SUNDAY NIGHT. EXPECT  
SHOWERS TO SPREAD ACROSS THE AREA WITH THIS SYSTEM SUNDAY NIGHT.  
MORE RAIN WILL FOLLOW MONDAY AS AN UPPER LEVEL LOW EJECTS NORTHEAST  
ALONG THE FRONT AND ACROSS THE OHIO RIVER. FOR THIS PACKAGE, FAVOR  
THE ECMWF THAT HAS BEEN CONSISTENT WITH A LARGE AREA OF DEFORMATION  
RAIN MONDAY INTO TUESDAY. THE EC HAS ALSO BEEN CONSISTENT WITH  
RAINFALL AMOUNTS OF 1 TO 3 INCHES DURING THIS PERIOD. FOR NOW, KEPT  
THE HEAVY RAIN MENTION IN THE HAZARDOUS WEATHER OUTLOOK. MUCH COLDER  
AIR WILL SPREAD ACROSS THE UPPER GREAT LAKES REGION TUESDAY  
ACCOMPANIED BY LAKE ENHANCED SHOWERS. LOWERED HIGHS TUESDAY TO  
AROUND 50 OVER MOST AREAS AS 850 MB TEMPS FALL BELOW 0C. THERE  
SHOULD BE A SHORT BREAK IN THE RAIN THURSDAY BEFORE EVEN COLDER AIR  
ARRIVES THIS COMING WEEKEND.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)  
ISSUED AT 721 PM EDT SAT OCT 21 2017  
 
VFR CONDITIONS EXPECTED THROUGH THE END OF THIS VALID PERIOD BUT  
CONDITIONS WILL LIKELY START TO DETERIORATE NEAR 00Z MONDAY AND  
BEYOND. RAIN SHOWERS LIKELY TO APPROACH KSBN LATE SUNDAY AFTERNOON  
BUT LOWERING CLOUD BASES STILL LOOK TO BE VFR UNTIL SUNDAY EVENING  
JUST BEYOND THIS VALID PERIOD.  
 

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

 
 

 
 
SYNOPSIS...LASHLEY  
SHORT TERM...SKIPPER  
LONG TERM...SKIPPER  
AVIATION...LASHLEY  
 
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