366  
FXUS63 KIND 120609  
AFDIND  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE INDIANAPOLIS IN  
209 AM EDT SAT SEP 12 2026  
   
KEY MESSAGES  
 
- SHOWERS AND EMBEDDED THUNDERSTORMS EARLY THIS MORNING, ESPECIALLY  
ACROSS THE SOUTHEAST HALF OF CENTRAL INDIANA  
 
- ADDITIONAL ISOLATED TO SCATTERED STORMS THIS AFTERNOON  
 
- SCATTERED STORMS SUNDAY AFTERNOON AND EVENING  
 
- HEAT RETURNING TUESDAY AND WEDNESDAY  
 
 
   
DISCUSSION (TODAY THROUGH FRIDAY)  
 
ISSUED AT 209 AM EDT SAT SEP 12 2026  
 
AN UPPER LEVEL WAVE WILL BRING SCATTERED SHOWERS AND EMBEDDED  
THUNDERSTORMS THIS MORNING FOCUSED MAINLY ACROSS THE SOUTHEAST HALF  
OF CENTRAL INDIANA. ADDITIONAL ISOLATED STORMS ARE POSSIBLE THIS  
AFTERNOON BEFORE WEAK HIGH PRESSURE BUILDS IN TONIGHT. AFTER A BRIEF  
COOLDOWN MONDAY...UPPER RIDGING WILL EXPAND NORTH INTO THE REGION  
THROUGH THE MIDDLE OF NEXT WEEK WITH HOT TEMPERATURES RETURNING. A  
COLD FRONT WILL BECOME NEARLY STATIONARY ACROSS THE LOWER GREAT  
LAKES BEFORE GRADUALLY SLIDING INTO THE OHIO VALLEY DURING THE  
SECOND HALF OF NEXT WEEK WITH INCREASING CHANCES FOR SHOWERS AND  
THUNDERSTORMS.  
 
TODAY THROUGH MONDAY NIGHT  
 
CLOUDS WERE INCREASING FROM THE SOUTHWEST EARLY THIS MORNING IN  
RESPONSE TO AN APPROACHING UPPER LEVEL WAVE. CONVECTION HAS BEEN  
ONGOING ACROSS THE WESTERN TENNESSEE AND LOWER OHIO VALLEYS SINCE  
FRIDAY EVENING AND HAD NOW ADVANCED INTO THE LOWER WABASH VALLEY.  
06Z TEMPERATURES RANGED FROM THE MID 60S NORTH TO THE MID 70S SOUTH.  
 
THE UPPER WAVE IS THE PRIMARY FEATURE OF INTEREST IN THE NEAR TERM  
AS IT PIVOTS ACROSS THE REGION THROUGH THIS AFTERNOON. AN ORGANIZED  
AREA OF CONVECTION WILL CONTINUE TO TRACK NORTHEAST ACROSS THE  
FORECAST AREA THROUGH DAYBREAK. WHILE STORMS HAVE HAD A HISTORY OF  
STRONGER WINDS ACROSS FAR SOUTHWEST INDIANA...ANTICIPATE A GRADUAL  
DECREASE IN INTENSITY AS IT LIFTS NORTHEAST THROUGH THE FORECAST  
AREA WITH LESS INSTABILITY PRESENT. THE MAIN CONCERN FROM THE STORMS  
WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS PWATS NEAR 2  
INCHES ADVECT INTO THE AREA AND THE AIRMASS BELOW 500MB IS  
EXCEPTIONALLY MOIST. HIGH RAINFALL RATES HAVE ALREADY BEEN NOTED  
WEST OF KEVV EARLIER AND WHILE A DOWNTREND IN CONVECTIVE INTENSITY  
SHOULD LEAD TO DIMINISHING RATES...THERE ARE LIKELY TO BE SOME  
LOCATIONS OVER THE LOWER WABASH VALLEY AND SOUTHERN PARTS OF THE  
FORECAST AREA THAT SEE A QUICK 1 TO 2 INCHES OF RAIN.  
 
THE WEAKENING AREA OF CONVECTION WILL MOVE EAST OF THE REGION DURING  
THE FIRST HALF OF THE MORNING WITH SCATTERED LIGHTER SHOWERS AND AN  
EXPANSION OF LOWER STRATUS ENVELOPING MUCH OF THE FORECAST AREA  
THROUGH MIDDAY. AS THE STRATUS MIXES OUT INTO A CU FIELD THIS  
AFTERNOON AND HEATING COMMENCES...POTENTIAL IS THERE FOR ISOLATED  
CONVECTION DEVELOPING ACROSS PRIMARILY THE EASTERN HALF OF THE  
FORECAST AREA ON THE BACK SIDE OF THE DEPARTING UPPER WAVE. MUCAPE  
LEVELS INCREASE TO 1000-2000 J/KG WITH ABUNDANT MOISTURE LINGERING.  
THE CONVECTION WILL SHIFT EAST BY EARLY EVENING AS THE UPPER WAVE  
MOVES AWAY TO THE EAST.  
 
WEAK HIGH PRESSURE BUILDS IN TONIGHT IN THE WAKE OF THE UPPER WAVE  
WITH CLOUD COVERAGE DIMINISHING. COULD AGAIN SEE PATCHY FOG NEAR  
DAYBREAK SUNDAY WITHIN THE MUGGY AIRMASS. SUNDAY WILL BEGIN DRY BUT  
THE APPROACH OF A COLD FRONT FROM THE NORTHWEST WILL SPREAD THE RISK  
FOR SCATTERED CONVECTION BACK INTO THE FORECAST AREA FOR THE  
AFTERNOON AND EVENING. A SURGE OF COOLER AND MUCH DRIER AIR WILL  
FOLLOW IN THE WAKE OF THE FRONTAL PASSAGE SUNDAY NIGHT AS A STRONG  
HIGH PRESSURE BUILDS INTO THE UPPER MIDWEST. THE HIGH WILL PIVOT  
ACROSS THE GREAT LAKES ON MONDAY WITH AN AXIS OF DEEP SUBSIDENCE  
SWINGING ACROSS THE AREA. RETURN SOUTHERLY FLOW WILL BEGIN TO DRAW  
MOISTURE BACK INTO THE REGION AS SOON AS MONDAY NIGHT WITH THE HIGH  
SHIFTING INTO NEW ENGLAND. THE UPPER RIDGE WILL ALSO PROGRESS  
TOWARDS THE OHIO VALLEY SETTING THE STAGE FOR A RETURN TO A HOTTER  
REGIME FOR TUESDAY AND WEDNESDAY.  
 
TEMPS...HIGHS TODAY WILL RANGE FROM AROUND 80 IN EASTERN PARTS OF  
THE FORECAST AREA WHERE CLOUDS AND THE THREAT FOR RAIN WILL LAST MUCH  
OF THE DAY...TO THE MID 80S IN THE WABASH VALLEY. LOW LEVEL THERMALS  
SUPPORT HIGHS IN THE LOW TO MID 80S SUNDAY AS WELL. WITH THE SUNDAY  
NIGHT FRONTAL PASSAGE...MONDAY TEMPERATURES WILL PLEASANT RANGING  
FROM THE MID 70S IN THE NORTHEAST TO THE LOWER 80S IN THE WABASH  
VALLEY.  
 
TUESDAY THROUGH FRIDAY  
 
RETURN SOUTHERLY FLOW WILL DEVELOP ON THE BACK SIDE OF THE DEPARTING  
HIGH QUICKLY ON TUESDAY AS MID LEVEL HEIGHTS RISE ACROSS THE OHIO  
VALLEY. HIGHS WILL LIKELY WARM BACK INTO THE LOWER AND POSSIBLY MID  
90S TUESDAY AND WEDNESDAY AS THE UPPER RIDGE CENTERS OVER THE  
TENNESSEE VALLEY. WITH A FRONTAL BOUNDARY STALLED TO THE NORTH OVER  
THE GREAT LAKES...CONVECTIVE RISKS WILL BE ISOLATED AND DIURNALLY  
DRIVEN AT BEST.  
 
A RETROGRESSION OF THE RIDGE INTO THE SOUTHERN PLAINS BY LATE WEEK  
WILL FINALLY ENABLE THE FRONT TO PRESS SOUTH INTO THE REGION WITH AN  
INCREASING THREAT FOR SCATTERED CONVECTION ACROSS THE FORECAST AREA.  
THE HEAT WILL BE PUSHED BACK SOUTH AS WELL WITH TEMPERATURES SLIDING  
INTO THE LOWER AND MID 80S BY FRIDAY THEN INTO THE UPPER 70S NEXT  
WEEKEND. EXTENDED MODEL GUIDANCE HAS BACKED OFF ON THE ARRIVAL OF A  
MUCH COOLER AIRMASS INTO THE REGION PERHAPS NOT UNTIL THE 10 TO 14  
DAY RANGE AS A MORE CHAOTIC QUASI-ZONAL FLOW ALOFT REMAINS ACROSS  
MUCH OF THE NORTHERN HALF OF THE COUNTRY BY NEXT WEEKEND.  
 
 
   
AVIATION (06Z TAF ISSUANCE)  
 
ISSUED AT 1235 AM EDT SAT SEP 12 2026  
 
IMPACTS:  
 
- SCATTERED TO NUMEROUS SHOWERS WITH EMBEDDED THUNDER PREDAWN HOURS  
TO NEAR DAYBREAK, ESPECIALLY AT KBMG AND KIND  
- PATCHY FOG POSSIBLE PREDAWN HOURS  
- MVFR CEILINGS DEVELOPING THROUGH MIDDAY  
- A FEW THUNDERSTORMS WILL DEVELOP MID TO LATE AFTERNOON  
 
DISCUSSION:  
 
A CONVECTIVE CLUSTER OVER THE LOWER OHIO VALLEY WILL LIFT NORTHEAST  
INTO THE REGION OVER THE NEXT SEVERAL HOURS. SHOULD SEE LIGHTNING  
STRIKES DIMINISH FROM CURRENT LEVELS AS IT LIFTS INTO SOUTHERN  
INDIANA BUT STILL FEEL SHORT TSRA TEMPO GROUPS ARE WARRANTED AT KBMG  
AND KIND BETWEEN 08Z AND 11Z. MVFR CEILINGS WILL ACCOMPANY THE  
SHOWERS AND SETTLE OVER ALL BUT KLAF AROUND OR SHORTLY AFTER  
DAYBREAK AS THE AREA OF RAIN SHIFTS AWAY TO THE NORTHEAST. PATCHY  
FOG MAY DEVELOP AT KLAF IN THE PREDAWN AS WELL.  
 
LOWER CLOUDS WILL LINGER INTO THE EARLY AFTERNOON BEFORE LIFTING  
INTO A BROKEN VFR CU FIELD. ENOUGH INSTABILITY WILL REMAIN FOR  
ISOLATED CONVECTIVE DEVELOPMENT THIS AFTERNOON ON THE BACK SIDE OF  
THE DEPARTING UPPER LEVEL WAVE...FOCUSED PRIMARILY OVER THE EASTERN  
HALF OF CENTRAL INDIANA. ANY RAIN THREAT WILL END BY EARLY EVENING  
WITH SKIES CLEARING AS WEAK HIGH PRESSURE BUILDS IN TONIGHT.  
 
 
   
IND WATCHES/WARNINGS/ADVISORIES  
NONE.  
 
 
 
 
 
AVIATION...RYAN  
DISCUSSION...RYAN  
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab IN Page
Main Text Page