919  
FXUS63 KIND 090634  
AFDIND  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE INDIANAPOLIS IN  
234 AM EDT SAT AUG 9 2025  
   
KEY MESSAGES  
 
- PATCHY SHALLOW GROUND FOG POSSIBLE THROUGH DAYBREAK  
 
- DRY, WARM AND HUMID CONDITIONS CONTINUE THROUGH THE WEEKEND  
 
- DAILY CHANCES FOR SCATTERED THUNDERSTORMS EXPECTED FOR MUCH OF  
NEXT WEEK WITH MUGGY CONDITIONS PERSISTING  
 
 
   
SHORT TERM (TODAY AND TONIGHT)  
 
ISSUED AT 234 AM EDT SAT AUG 9 2025  
 
CLEAR SKIES EARLY THIS MORNING WITH LIGHT SOUTHEAST WINDS AS RIDGING  
ALOFT AND AT THE SURFACE HOLDS SERVE ACROSS THE OHIO VALLEY. 06Z  
TEMPERATURES WERE IN THE LOW AND MID 70S WITH A MUGGY AIRMASS IN  
PLACE.  
 
TODAY LOOKS TO BE A NEAR CARBON COPY OF WHAT WAS EXPERIENCED FRIDAY  
AS BROAD RIDGING REMAINS ACROSS MUCH OF THE EASTERN PART OF THE  
COUNTRY MAINTAINING A WARM AND HUMID AIRMASS WITH DRY CONDITIONS  
ACROSS THE FORECAST AREA. THE PRESENCE OF THE RIDGING ALOFT WILL  
BLOCK A SIGNIFICANT EASTWARD MOVEMENT TO A STRONGER UPPER LOW  
DRIFTING THROUGH THE NORTHERN PLAINS. A COLD FRONT WILL SHIFT EAST  
INTO THE UPPER MIDWEST AND MISSOURI VALLEY BY LATE TODAY AND  
TONIGHT. THE BOUNDARY WILL BE A FOCAL POINT FOR ROBUST CONVECTIVE  
DEVELOPMENT BUT DUE TO THE RIDGING OVER THE REGION WILL NOT MAKE ANY  
FURTHER PROGRESS EASTWARD THROUGH THE SHORT TERM.  
 
LOCALIZED SHALLOW GROUND FOG IS A POSSIBILITY THROUGH DAYBREAK BUT  
OVERALL COVERAGE WILL BE LOWER THAN FRIDAY MORNING AS THE BOUNDARY  
LAYER HAS HAD A FULL DAY TO DRY OUT FROM CONVECTION EARLIER THIS  
WEEK. DIURNAL CU WILL DEVELOP FOR THE AFTERNOON BUT SHOULD REMAIN  
GENERALLY FLAT AND SCATTERED WITH A MID LEVEL CAP PERSISTING OVER  
THE REGION. MODEST INSTABILITY WILL AGAIN DEVELOP FOR THE AFTERNOON  
BUT THE PRESENCE OF THE CAP WITH WARM AND SUBSIDENT AIR WITHIN THE  
MID LEVELS WILL MITIGATE ANY POTENTIAL FOR ISOLATED CONVECTION  
DURING PEAK HEATING. MODEL SOUNDINGS DO SHOW A WELL MIXED BOUNDARY  
LAYER WITH DRY ADIABATIC FLOW FOR THE AFTERNOON WHICH MAY ENABLE  
SLIGHTLY DRIER AIR TO BE DRAWN TO THE SURFACE DURING PEAK HEATING  
WHILE ALSO SUBTLY INCREASING SOUTHERLY WINDS.  
 
CU AND WINDS WILL DIMINISH THIS EVENING WITH LOSS OF HEATING SETTING  
THE STAGE FOR ANOTHER MUGGY NIGHT WITH NEAR CALM SURFACE WINDS.  
CONVECTIVE CLUSTERS DEVELOPING ALONG THE BOUNDARY TO THE NORTHWEST  
MENTIONED ABOVE WILL NOT HAVE ANY IMPACT LOCALLY ACROSS CENTRAL  
INDIANA BUT MAY SEE A SUBTLE INCREASE IN HIGH CLOUDS FROM THE STORMS  
MOVE INTO THE REGION BY SUNDAY MORNING.  
 
TEMPS...LOW LEVEL THERMALS SUPPORT SIMILAR TEMPERATURES TO FRIDAY  
WITH HIGHS IN THE UPPER 80S TO LOWER 90S. LOWS TONIGHT WILL BE  
AROUND 70.  
 
 
   
LONG TERM (SUNDAY THROUGH FRIDAY)  
 
ISSUED AT 234 AM EDT SAT AUG 9 2025  
 
A STAGNANT PATTERN ALOFT WILL DEVELOP ACROSS THE EASTERN HALF OF THE  
COUNTRY AS RIDGING SITS IN PLACE INTO THE FIRST PART OF THE WEEK AND  
BLOCKS A NORTHERN STREAM TROUGH FROM EXPANDING SOUTHEAST. THIS WILL  
MAINTAIN A VERY WARM AND HUMID AIRMASS ACROSS THE OHIO VALLEY OVER  
THE NEXT FEW DAYS. THE UPPER LEVEL FLOW WILL TRANSITION TO MORE OF A  
QUASI-ZONAL REGIME THROUGHOUT THE UPCOMING WEEK WHICH WILL ENABLE  
WEAK WAVES ALOFT TO DROP FURTHER SOUTH INTO THE REGION WITH DAILY  
THREATS FOR SCATTERED CONVECTION FOCUSED MAINLY FROM TUESDAY GOING  
FORWARD INTO NEXT WEEKEND.  
 
SUNDAY THROUGH MONDAY NIGHT  
 
A TYPICAL HUMID MIDSUMMER AIRMASS WILL PERSIST ACROSS THE OHIO  
VALLEY WITH RIDGING ALOFT AND AT THE SURFACE WITH DAILY HIGHS/LOWS  
WITHIN A FEW DEGREES EITHER SIDE OF 90 AND 70 DEGREES RESPECTIVELY  
BOTH SUNDAY AND MONDAY. THE HEATING WILL BREED MODERATE INSTABILITY  
LEVELS EACH DAY THROUGH MONDAY DESPITE A LINGERING MID LEVEL CAP.  
THERE WILL BE A NONZERO CONVECTIVE THREAT BUT IT WILL BE DIFFICULT  
TO SEE MUCH MORE THAN A FEW STRAY SHOWERS OR STORMS CONSIDERING THE  
MITIGATING FACTORS MENTIONED ABOVE. WILL CONTINUE WITH A DRY  
FORECAST SUNDAY BUT AS THE CAP WEAKENS SLIGHTLY BY MONDAY LOW CHANCE  
POPS FOR ISOLATED STORMS ARE WARRANTED BY THE AFTERNOON.  
 
TUESDAY THROUGH FRIDAY  
 
THE FLATTENING OF THE UPPER LEVEL FLOW WILL ENABLE UPPER LEVEL WAVES  
TO TRACK FURTHER SOUTH WITH SCATTERED CONVECTION DEVELOPING EACH DAY  
AND FOCUSING DURING THE PEAK HEATING HOURS OF THE AFTERNOON AND  
EARLY EVENING. WHILE RUN TO RUN CONSISTENCY AMONGST THE MODEL SUITE  
REMAINS LESS THAN DESIRED...THE STRONGEST OF THE WAVES ALOFT WILL  
COME THROUGH THE AREA TUESDAY INTO WEDNESDAY WITH THE BEST  
CHANCES FOR STORMS IN THE EXTENDED LIKELY COMING BOTH DAYS. THE  
MAIN CONVECTIVE RISKS WILL BE HEAVY RAINFALL AND LOCALIZED  
FLOODING AS A LACK OF SUBSTANTIAL SHEAR WILL ENSURE SLOW MOVEMENT  
TO STORMS THAT WILL PULSE UP AND DOWN IN INTENSITY. THERE IS  
ALWAYS THE POTENTIAL FOR A CELL TO STRENGTHEN ENOUGH BRIEFLY TO  
PRODUCE LOCALIZED DOWNBURSTS AS THE CORES COLLAPSE BUT THAT IS  
LIKELY TO REMAIN A SECONDARY CONCERN THROUGHOUT THE PERIOD.  
 
EXPECT VIRTUALLY NO CHANGE IN AIRMASS ALL NEXT WEEK AND LIKELY INTO  
THE WEEKEND AS WELL. MUGGY CONDITIONS WILL PERSIST WITH HIGHS IN THE  
MID AND UPPER 80S AND DEWPOINTS LIKELY CREEPING UP A BIT INTO THE  
LOWER 70S. SIGNS CONTINUE TO INCREASE IN LITTLE TO NO CHANGE IN THE  
PATTERN FOR NEXT WEEK BEYOND THE 7 DAY PERIOD INTO THE FOLLOWING  
WEEK AS COOLER AND DRIER AIR REMAINS BOTTLED UP WELL TO THE NORTH OF  
CENTRAL INDIANA.  
 
 
   
AVIATION (06Z TAF ISSUANCE)  
 
ISSUED AT 1217 AM EDT SAT AUG 9 2025  
 
IMPACTS:  
 
- FOG POSSIBLE AT THE OUTLYING TAF SITES AGAIN TOWARDS DAYBREAK  
 
DISCUSSION:  
 
VFR CONDITIONS ARE EXPECTED FOR THE BULK OF THE FORECAST PERIOD.  
SHALLOW GROUND FOG MAY DEVELOP AGAIN DURING THE PREDAWN HOURS AT  
ALL THE OUTLYING TAF SITES...BUT SHOULD BE LESS IMPACTFUL COMPARED  
TO EARLY FRIDAY MORNING DUE TO DRIER SOIL. WILL GO WITH A BRIEF  
PERIOD OF MVFR AROUND DAYBREAK...BUT BRIEF LOWER VISIBILITIES CANNOT  
BE RULED OUT. FOG WILL QUICKLY MIX OUT AFTER DAYBREAK WITH QUIET  
WEATHER THROUGH TONIGHT. SCATTERED DIURNAL CU IS EXPECTED DURING THE  
AFTERNOON WITH SOUTHERLY WINDS AROUND 10KTS.  
 
 
   
IND WATCHES/WARNINGS/ADVISORIES  
NONE.  
 
 
 
 
 
SHORT TERM...RYAN  
LONG TERM...RYAN  
AVIATION...RYAN  
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