521  
FXUS63 KIWX 211739  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
139 PM EDT THU OCT 21 2021  
   
SYNOPSIS
 
 
ISSUED AT 653 AM EDT THU OCT 21 2021  
 
NOTABLY COOLER TODAY WITH NEARLY STEADY TEMPERATURES. SCATTERED  
SHOWERS AND ISOLATED THUNDERSTORMS EAST OF INTERSTATE 69 WILL  
TAPER OFF BY LATE MORNING. HOWEVER, ADDITIONAL RAIN SHOWERS ARE  
POSSIBLE FOR SOME THIS AFTERNOON. OTHERWISE, EXPECT PARTLY TO  
MOSTLY CLOUDY SKIES WITH GUSTY WEST WINDS AND TEMPERATURES IN THE  
50S. SEASONABLY COOL THIS WEEKEND WITH WET WEATHER POSSIBLE  
SUNDAY.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 409 AM EDT THU OCT 21 2021  
 
SHOWERS AND THUNDERSTORMS ALONG A COLD FRONT WILL EXIT FROM WEST TO  
EAST THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. THE PARENT  
UPPER- LEVEL LOW WILL GRADUALLY MEANDER EAST TODAY THROUGH  
SOUTHERN MICHIGAN. ADEQUATE MOISTURE IS FOUND IN THE LOW- LEVELS,  
AND SHOWERS ARE ONGOING IN THE VICINITY OF THE UPPER-LEVEL LOW.  
SO, RAIN SHOWERS WILL REMAIN IN THE FORECAST TODAY FOR THOSE  
NORTH OF US 24. LAPSE RATES AND INSTABILITY ARE MAXIMIZED ALONG  
THE COLD FRONT, SO THE CHANCE OF THUNDER THIS AFTERNOON FROM THE  
UPPER- LEVEL LOW IS MINIMAL.  
 
DRY AIR ARRIVES OVERNIGHT, BRINGING AN END TO THE RAIN CHANCES.  
SEASONABLY COLD TONIGHT WITH LOWS NEAR 40 FOR MOST; MID- 40S FOR  
THOSE TOWARD WEST-CENTRAL INDIANA. AS AN ASIDE, THROUGH THE 20TH,  
FORT WAYNE IS STILL EXPERIENCING THE WARMEST START TO OCTOBER WITH  
AN AVERAGE TEMPERATURE OF 64.6. SOUTH BEND IS SEEING THEIR 2ND  
WARMEST (BEHIND OCTOBER 1928), WITH AN AVERAGE TEMPERATURE OF  
65.3.  
 

 
   
LONG TERM
 
(FRIDAY THROUGH WEDNESDAY)  
ISSUED AT 409 AM EDT THU OCT 21 2021  
 
CYCLONIC FLOW ALOFT WILL PREVAIL FRIDAY AND SATURDAY THANKS TO AN  
UPPER-LEVEL LOW OVER EASTERN ONTARIO. THIS SENDS LOBES OF VORTICITY  
THROUGH OUR AREA, WITH PERHAPS THE MOST PRONOUNCED LOBE PASSING  
THROUGH FRIDAY NIGHT/SATURDAY. MOISTURE ALOFT IS LACKING BY THAT  
TIME, SO THE DRY FORECAST WILL CONTINUE. OUR COLDEST LOWS OF THE  
FALL SEASON LOOM SATURDAY NIGHT, ESPECIALLY IN SOUTH- CENTRAL  
MICHIGAN WHERE LOWS IN THE MID-30S ARE FORECAST. PATCHY FROST HAS  
BEEN INTRODUCED.  
 
A WARM FRONT LIFTS IN ON SUNDAY AND STALLS OVER OUR AREA, LIKELY  
BRINGING WIDESPREAD RAIN TO THE AREA AS THE DAY PROGRESSES. FLOW  
THROUGH THE MID-LEVELS IS PARALLEL TO THE WARM FRONT AND CONVERGENT  
OVER NORTHERN INDIANA. THIS IS PAIRED WITH PWATS NEAR THE 90TH  
PERCENTILE FOR THIS TIME OF YEAR. AS A RESULT, THERE IS A NON-  
ZERO THREAT OF LOCALLY HEAVY RAIN. THE SURFACE LOW EXITS MONDAY  
NIGHT AT WHICH POINT RAIN CHANCES GRADUALLY DIMINISH.  
 
WE'LL MOST LIKELY BE BETWEEN SYSTEMS BY MIDWEEK WITH A TROUGH TO  
BOTH OUR WEST AND OUR EAST. DETERMINISTIC MODELS HAVE TRENDED DRY  
ON WEDNESDAY WITH THIS 00Z RUN, BUT ENSEMBLES STILL OFFER THE  
CHANCE FOR WET WEATHER. I HAVE BLENDED THE PREVIOUS AND LATEST  
FORECASTS, WITH A FURTHER POP REDUCTION THEREAFTER. THE WESTERN  
TROUGH AXIS SWINGS THROUGH THURSDAY NIGHT.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 139 PM EDT THU OCT 21 2021  
 
A COLD FRONT HAS BEEN TRAVERSING WEST TO EAST ACROSS THE REGION  
TODAY. LATEST RADAR TRENDS HAVE SHOWN THE INITIAL PRECIPITATION  
TO BE WELL EAST OF THE TERMINAL SITES. WITH THE APPROACH OF THE  
UPPER LOW REDEVELOPMENT OF SHRA IS EXPECTED THIS AFTN THAT COULD  
IMPACT THE KSBN TERMINAL LATER IN THE AFTN/EVENING TIME PERIOD.  
EXPECT MVFR CIGS AT KSBN THROUGH THE FCST PD WHILE BEGINNING AS  
MVFR AT KFWA AND IMPROVING TO VFR AFTER 08Z TONIGHT. WEST WINDS  
GUSTING TO 25 KTS AT TIMES WILL TURN NW THIS EVENING CLOSER TO  
00Z.  
 

 
   
IWX WATCHES/WARNINGS/ADVISORIES
 
 
IN...NONE.  
MI...NONE.  
OH...NONE.  
LM...SMALL CRAFT ADVISORY UNTIL 11 AM EDT FRIDAY FOR LMZ043-046.  
 

 
 

 
 
SYNOPSIS...BROWN  
SHORT TERM...BROWN  
LONG TERM...BROWN  
AVIATION...MF  
 
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  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab IN Page
The Nexlab OH Page
The Nexlab MI Page Main Text Page