222  
FXUS63 KIWX 221041  
AFDIWX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NORTHERN INDIANA  
641 AM EDT SUN OCT 22 2017  
   
SYNOPSIS
 
 
ISSUED AT 350 AM EDT SUN OCT 22 2017  
 
ANOTHER UNSEASONABLY WARM DAY IS EXPECTED TODAY WITH HIGHS INTO  
THE 70S. CHANCES FOR RAIN WILL INCREASE WEST OF INTERSTATE 69  
LATER TODAY INTO TONIGHT ALONG A FRONTAL BOUNDARY. RAIN WILL  
LIKELY ENGULF THE ENTIRE FORECAST AREA MONDAY INTO MONDAY EVENING  
AS LOW PRESSURE DEVELOPS INTO THE GREAT LAKES REGION. RAINFALL  
AMOUNTS BETWEEN 1 AND 3 INCHES WILL BE POSSIBLE IN NORTHEAST  
INDIANA, NORTHWEST OHIO, AND SOUTH-CENTRAL LOWER MICHIGAN. MUCH  
COOLER AND SHOWERY WEATHER IS EXPECTED BEHIND THIS SYSTEM INTO  
TUESDAY AND WEDNESDAY, WITH HIGHS ON WEDNESDAY LIKELY STRUGGLING  
TO GET OUT OF THE 40S.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 350 AM EDT SUN OCT 22 2017  
 
MILD AND SOMEWHAT BRISK SOUTHWEST FLOW WILL YIELD ANOTHER UNUSUALLY  
WARM LATE OCTOBER DAY WITH HIGHS ONCE AGAIN WELL INTO THE 70S.  
CLOUDS AND CHANCES FOR RAIN WILL INCREASE INTO NW IN/SW LOWER MI  
LATER TODAY INTO THIS EVENING, AND TOWARD THE I-69 CORRIDOR TONIGHT,  
AS A FRONTAL BOUNDARY AND ASSOCIATED DEEP MOISTURE PLUME SLOWS EAST  
INTO THE LOCAL AREA. THESE FEATURES EXIST ON THE LEADING EDGE OF A  
DEEP CENTRAL US UPPER TROUGH. ENERGY WITHIN THE TROUGH WILL SPLIT  
WITH SOUTHERN PIECE TOWARD THE LOWER MS VALLEY AND NORTHERN STREAM  
JET ENERGY NORTHEAST THROUGH THE NORTHERN GREAT LAKES AND ONTARIO.  
THE RESULT WILL BE A WEAKENING/SLOWING TREND TO THE AFOREMENTIONED  
FRONTAL CIRCULATION ONCE IT REACHES OUR AREA. WITH THAT SAID, AT  
LEAST LIGHT RAIN SHOULD ACCOMPANY THE FRONT BY TONIGHT INTO AREAS  
MAINLY WEST OF I-69 GIVEN AMPLE MOISTURE, WEAK HEIGHT FALLS, AND  
RIGHT ENTRANCE UPPER JET ASSOCIATED WITH THE NORTHERN STREAM  
ENERGY.  
 

 
   
LONG TERM
 
(MONDAY THROUGH SATURDAY)  
ISSUED AT 350 AM EDT SUN OCT 22 2017  
 
A PATTERN CHANGE TO A MUCH MORE ACTIVE/WET/COOLER REGIME THE STORY  
NEXT WEEK/WEEKEND...  
 
A POWERHOUSE NORTHEAST PACIFIC JET WILL EVENTUALLY HELP TO CARVE OUT  
A RATHER IMPRESSIVE NEGATIVE HEIGHT ANOMALY OVER THE EASTERN US BY  
TUESDAY AND WEDNESDAY. PHASE OF THIS JET ENERGY WITH LEFTOVER  
SOUTHERN STREAM WAVE, A COUPLED JET STRUCTURE, AND SURGE OF GULF  
MOISTURE SHOULD ALLOW A DEEPENING SFC CYCLONE TO TRACK NORTHEAST  
ALONG FRONTAL BOUNDARY MONDAY INTO MONDAY NIGHT IN THIS  
TRANSITION. FAVOR THE STRONGER/FARTHER WEST/WETTER SOLUTIONS OF  
ECMWF/GEM/UKMET OVER THE GFS/NAM AT THIS TIME RESULTING IN A BUMP  
TO QPF/POPS...ESPECIALLY ACROSS NE IN/SC LOWER MI/NW OH NEAR  
DEFORMATION PIVOT. RAINFALL TOTALS IN THE 1-3 INCH RANGE APPEAR  
POSSIBLE HERE.  
 
STRONG COLD ADVECTION WING WRAPS IN UNDER LOW PRESSURE ON TUESDAY  
WITH BREEZY/SHARPLY COLDER CONDITIONS. SHOULD ALSO SEE SCATTERED  
TO NUMEROUS RAIN SHOWERS GIVEN EXPECTED LAKE ENHANCEMENT AND MOIST  
CYCLONIC FLOW WITHIN DEEP TROUGH AXIS. ADDITIONAL TRAILING  
SHORTWAVE ENERGY INTO THE UPPER TROUGH MAY SUPPORT ADDITIONAL LAKE  
ENHANCED SHOWER ACTIVITY INTO WEDNESDAY. HIGH TEMPERATURES ON  
WEDNESDAY ARE NOT EXPECTED TO GET OUT OF THE 40S IN MOST LOCATIONS  
(10-15 DEGREES BELOW NORMAL).  
 
FAIR WX AND BRIEF WARMING IS EXPECTED INTO THURSDAY AND POSSIBLY  
FRIDAY AS SHORTWAVE RIDGING WORKS THROUGH IN BETWEEN SYSTEMS. THE  
NEXT UPPER TROUGH IS MODELED TO AMPLIFY INTO THE CENTRAL US BY LATER  
FRIDAY AND NEXT WEEKEND. MODELS DIFFER ON TIMING OF A STRENGTHENING  
BAROCLINIC ZONE ON THE LEADING EDGE. COVERED WITH BROADBRUSH CHANCE  
POPS FOR RAIN AND COOLING TEMPS FOR NOW.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)  
ISSUED AT 640 AM EDT SUN OCT 22 2017  
 
CONDITIONS STILL ON TRACK FOR AN INITIALLY SLOW DETERIORATION  
THIS EVENING AT KSBN AND DURING THE OVERNIGHT HOURS OF MONDAY FOR  
KFWA. WHILE KSBN WILL LIKELY DROP INTO IFR NEAR/AFTER 6Z MONDAY.  
HAVE CONTINUED A DOWNWARD TREND, BUT NOT INTRODUCED THAT LOW QUIET  
YET. AT KFWA, FLIGHT CONDITION IMPACTS MAY NOT OCCUR UNTIL CLOSER  
TO THE END OF THE PERIOD WITH SLOW ARRIVAL OF THE PRECIP. HAVE  
KEPT VFR CONDITIONS THROUGH THE PERIOD, BUT WILL LIKELY NEED TO  
DROP FURTHER WITH NEXT FORECAST.  
 

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

 
 

 
 
SYNOPSIS...STEINWEDEL  
SHORT TERM...STEINWEDEL  
LONG TERM...STEINWEDEL  
AVIATION...FISHER  
 
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