682  
FXUS63 KIND 201833  
AFDIND  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE INDIANAPOLIS IN  
233 PM EDT SUN SEP 20 2026  
   
KEY MESSAGES  
 
- SCATTERED TO NUMEROUS SHOWERS AND STORMS LATE TODAY THROUGH TONIGHT  
 
- AN ISOLATED SEVERE STORM WITH DAMAGING WINDS THROUGH EARLY  
EVENING BUT LOCALLY HEAVY RAIN REMAINS THE PRIMARY THREAT.  
 
- MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WEEK, GRADUALLY  
WARMING BACK TO NEAR NORMAL LEVELS BY NEXT WEEKEND  
 
 
   
DISCUSSION (THIS EVENING THROUGH SUNDAY)  
 
ISSUED AT 233 PM EDT SUN SEP 20 2026  
 
A SLOW MOVING COLD FRONT WILL REMAIN THE FOCAL POINT FOR PERIODIC  
CONVECTION TONIGHT INTO EARLY MONDAY. THE FRONT WILL MOVE SOUTH OF  
THE OHIO RIVER ON MONDAY BUT ISOLATED SHOWERS WILL REMAIN POSSIBLE  
INTO EARLY TUESDAY PRIOR TO THE PASSAGE OF AN UPPER LEVEL WAVE. MUCH  
COOLER AIR WILL OVERSPREAD THE REGION IN THE WAKE OF THE FRONT. AN  
UPPER LOW WILL CUTOFF OVER THE MID ATLANTIC DURING THE SECOND HALF  
OF THE WEEK...WITH MUCH DRIER AIR BEING PULLED SOUTH INTO THE OHIO  
VALLEY. THIS WILL RESULT IN PLEASANT EARLY FALL CONDITIONS LATE THIS  
WEEK INTO THE UPCOMING WEEKEND.  
 
REST OF TODAY THROUGH TUESDAY NIGHT  
 
MID AND HIGH LEVEL CLOUDS CONTINUE TO OVERSPREAD THE REGION THIS  
AFTERNOON WITH A FRONTAL BOUNDARY DRAPED ACROSS CENTRAL INDIANA.  
TEMPERATURES VARIED ACROSS THE BOUNDARY...RANGING FROM THE MID 70S  
OVER NORTH CENTRAL INDIANA TO NEAR 90 ALONG OUR SOUTHERN BORDER AT  
18Z.  
 
THE FRONTAL BOUNDARY WILL SERVE AS A FOCAL POINT FOR RENEWED  
CONVECTIVE DEVELOPMENT LATE TODAY INTO TONIGHT AS A SURFACE WAVE  
RIDES ALONG IT. SHOWERS OVER NORTHWEST INDIANA WILL DRIFT EAST WITH  
ADDITIONAL DEVELOPMENT BACK TO THE WEST ACROSS ILLINOIS. WHILE  
INITIAL MOVEMENT SHOULD KEEP THE BULK OF THE SHOWERS AND STORMS  
LARGELY TO THE NORTH OF THE FORECAST AREA...EXPECT A GRADUAL  
SOUTHERN DRIFT INTO THE NORTHEAST HALF OF THE FORECAST AREA BY EARLY  
EVENING WITH ADDITIONAL SHOWERS AND STORMS RIDING ALONG THE BOUNDARY  
OVERNIGHT.  
 
THERE REMAINS A NON-ZERO THREAT FOR A FEW SEVERE STORMS BUT OVERALL  
THE THERMODYNAMICS REMAIN UNIMPRESSIVE. PEAK CAPE VALUES ARE ONLY AT  
ABOUT 1000 J/KG WITH LIMITED BL SHEAR. THERE IS A NARROW WINDOW  
BETWEEN NOW AND 22-23Z WHERE MLCAPE VALUES MAY NUDGE UP SLIGHTLY IN  
AN AXIS ALONG AND JUST NORTH OF THE FRONT ACROSS THE NORTHERN HALF  
OF THE FORECAST AREA WHERE ANY STRONGER CELL THAT CAN DEVELOP MAY  
CARRY AN ISOLATED DAMAGING WIND RISK. ALL IN ALL THOUGH...THE  
SEVERE RISK APPEARS VERY LOW INTO THIS EVENING.  
 
THE GREATER THREAT FROM CONVECTION WILL BE LOCALLY HEAVY RAINFALL AS  
AN AXIS OF PWATS IN EXCESS OF 1.75 INCHES PIVOTS SOUTH ACROSS THE  
AREA TONIGHT. MODEL SOUNDINGS CONTINUE TO ADVERTISE A DEEP WARM LAYER  
UP TO NEAR 500MB AND THE PRESENCE OF A MODEST WESTERLY LOW LEVEL JET  
TONIGHT ALL SUPPORT POTENTIAL FOR EFFICIENT RAINFALL RATES AND SOME  
BACKBUILDING OF SHOWERS AND STORMS IN THE VICINITY OF THE BOUNDARY.  
BRIEFLY CONSIDERED A FLOOD WATCH OVER FAR NORTHEAST PORTIONS OF THE  
FORECAST AREA FOR TONIGHT BUT THE BULK OF THE HEAVIER RAINFALL OVER  
THE LAST 72 HOURS HAS BYPASSED US TO THE NORTH AND EAST. 1- AND 3-  
HOUR FLASH FLOOD GUIDANCE NUMBERS ARE MANAGEABLE AND ALSO ARGUE  
AGAINST A FLOOD WATCH. WILL CERTAINLY MONITOR CONVECTIVE TRENDS INTO  
THE EVENING BUT WILL NOT CARRY ANY FLOOD HEADLINES AT THIS TIME.  
 
SHOWERS WILL LINGER INTO MONDAY BUT COVERAGE WILL STEADILY DECREASE  
THROUGHOUT THE DAY AS THE FRONT SHIFTS INTO THE TENNESSEE VALLEY.  
ABUNDANT MOISTURE WILL PERSIST THROUGH THE BOUNDARY LAYER HOWEVER  
TRAPPED BENEATH A STOUT INVERSION. THIS WILL KEEP SKIES MOSTLY  
CLOUDY THROUGH MONDAY NIGHT AND LIKELY EVEN INTO TUESDAY AS AN UPPER  
WAVE APPROACHES FROM THE NORTHWEST. CANNOT RULE OUT A FEW SHOWERS  
MONDAY NIGHT AND TUESDAY BUT WILL BE ISOLATED AT BEST WITH MOISTURE  
LARGELY CONFINED TO THE BOUNDARY LAYER. A DECREASE IN CLOUDS WILL  
COMMENCE TUESDAY NIGHT AS DRIER AIR ATTEMPTS TO ADVECT SOUTH ON THE  
BACK SIDE OF THE DEPARTING WAVE ALOFT. THE DEVELOPMENT OF AN UPPER  
LOW OVER THE EASTERN GREAT LAKES TUESDAY NIGHT MAY SERVE HOWEVER TO  
DELAY MORE SUBSTANTIAL CLEARING FROM THE WEST.  
 
TEMPS...TODAY WILL BE THE LAST VERY WARM DAY AS THE PASSAGE OF THE  
FRONT BY EARLY MONDAY WILL ADVECT MUCH COOLER AIR INTO THE REGION  
FROM THE NORTH. LOW LEVEL THERMALS SUPPORT HIGHS IN THE UPPER 60S  
NORTH TO NEAR 80 IN THE LOWER WABASH VALLEY MONDAY WITH UPPER 60S TO  
LOWER 70S TUESDAY. THE CURRENT FORECAST HIGH OF 69 DEGREES FOR KIND  
FOR TUESDAY WOULD BE THE FIRST SUB-70 DEGREE DAY SINCE MAY 23. LOWS  
WILL TRANSITION DOWN INTO THE LOWER AND MIDDLE 50S BY MONDAY/TUESDAY  
NIGHTS AS WELL.  
 
WEDNESDAY THROUGH SUNDAY  
 
STRONG SIGNALS IN THE EXTENDED MODEL SUITE SUGGEST THE  
AFOREMENTIONED UPPER LOW WILL AMPLIFY AND BECOME CUTOFF FROM THE  
MEAN FLOW ALOFT OVER THE MID ATLANTIC REGION DURING THE SECOND HALF  
OF THE WEEK. COOL E/NE FLOW AND AT LEAST SOME LINGERING CLOUD COVER  
ON THE BACK SIDE OF THE DEVELOPING CUTOFF LOW WILL MAINTAIN BELOW  
NORMAL TEMPERATURES WEDNESDAY AND FOR PARTS OF THE AREA THURSDAY AS  
WELL WITH HIGHS RANGING FROM THE UPPER 60S TO THE MID 70S FROM  
NORTHEAST TO SOUTHWEST. A FEW LIGHT SHOWERS CANNOT BE ENTIRELY RULED  
OUT OVER FAR EASTERN PORTIONS OF THE FORECAST AREA WEDNESDAY BUT  
CONFIDENCE IS FAR TOO LOW FOR A MENTION IN THE FORECAST AS BETTER  
FORCING ALOFT WILL BE EAST OF THE REGION.  
 
AS THE UPPER LOW BECOMES BETTER ORGANIZED OVER THE MID ATLANTIC  
FRIDAY INTO THE WEEKEND...AN AXIS OF DEEPENING SUBSIDENCE WILL BE  
ADVECTED SOUTH FROM CANADA AND ACROSS THE OHIO VALLEY. A NARROW  
RIDGE ALOFT WILL EXPAND INTO THE AREA ALLOWING TEMPERATURES TO  
RECOVER BACK TO LATE SEPTEMBER NORMALS WITH ABUNDANT SUNSHINE AND  
PLEASANT EARLY AUTUMN CONDITIONS FOR THE FORECAST AREA. HIGHS WILL  
BE IN THE 70S THIS WEEKEND WITH LOW 80S POSSIBLE ACROSS THE  
SOUTHWEST HALF OF THE AREA BY SUNDAY. COMFORTABLE LOWS IN THE 50S  
ARE EXPECTED THROUGHOUT THE PERIOD...ALTHOUGH A FEW LOCATIONS OVER  
NORTHEAST COUNTIES MAY SLIP INTO THE UPPER 40S MAINLY THURSDAY  
THROUGH SATURDAY NIGHTS.  
 
 
   
AVIATION (18Z TAF ISSUANCE)  
 
ISSUED AT 1232 PM EDT SUN SEP 20 2026  
 
IMPACTS:  
 
- SCATTERED CONVECTION LATE TODAY THROUGH TONIGHT AND INTO MONDAY  
MORNING  
- DETERIORATING CEILINGS THIS EVENING WITH IFR CONDITIONS DEVELOPING  
OVERNIGHT INTO MONDAY MORNING  
- WINDS BECOMING NORTHEAST TONIGHT AND MONDAY  
 
DISCUSSION:  
 
A FRONTAL BOUNDARY BISECTS CENTRAL INDIANA EARLY THIS AFTERNOON WITH  
WINDS ALREADY HAVING SHIFTED TO A NORTHERLY DIRECTION AT ALL BUT  
KBMG. MID AND HIGH LEVEL CLOUDS WERE INCREASING OVER THE AREA...WITH  
AN AXIS OF SCATTERED CU IN THE VICINITY OF THE FRONT. THE FRONT  
WILL CONTINUE A SLOW SOUTHWARD DRIFT THROUGH THE REST OF THE  
AFTERNOON AND WILL PASS THROUGH KBMG BY EARLY EVENING.  
 
THE APPROACH OF A SURFACE WAVE ALONG THE BOUNDARY LATER TODAY WILL  
LEAD TO AN INCREASE IN CONVECTIVE DEVELOPMENT EXTENDING INTO  
TONIGHT. COULD SEE BRIEF RESTRICTIONS WITHIN ANY HEAVIER SHOWERS OR  
STORMS BUT THE PRIMARY IMPACT TO AVIATORS WILL BE THE EXPANSION OF A  
BROAD STRATUS DECK FROM NORTH TO SOUTH LATE THIS AFTERNOON INTO THE  
EVENING. CEILINGS WILL EVENTUALLY SETTLE INTO THE IFR CATEGORY  
OVERNIGHT WITH MODEL SOUNDINGS SHOWING SATURATED CONDITIONS IN THE  
LOW LEVELS. CEILINGS MAY LIFT BACK INTO MVFR LEVELS BY LATE MORNING  
MONDAY AS SHOWERS DECREASE IN COVERAGE. NORTHEAST WINDS WILL REMAIN  
AROUND 10KTS TONIGHT AND MONDAY WITH THE POTENTIAL FOR PERIODIC  
GUSTS AT KLAF.  
 
 
   
IND WATCHES/WARNINGS/ADVISORIES  
NONE.  
 
 
 
 
 
AVIATION...RYAN  
DISCUSSION...RYAN  
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