479
FXUS63 KIND 031852
AFDIND
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE INDIANAPOLIS IN
252 PM EDT THU SEP 3 2026
KEY MESSAGES
- HEAT ADVISORY IN EFFECT FOR ALL OF CENTRAL INDIANA THROUGH LATE
FRIDAY WITH PEAK AFTERNOON HEAT INDEX VALUES UP TO 108 DEGREES
- ISOLATED TO SCATTERED THUNDERSTORMS WILL BE POSSIBLE AT TIMES
FRIDAY AND SATURDAY
DISCUSSION (THIS EVENING THROUGH THURSDAY)
ISSUED AT 252 PM EDT THU SEP 3 2026
RIDGING WILL CONTINUE TODAY ACROSS CENTRAL INDIANA, BUT A SHORTWAVE
WILL DEVELOP ON THE PERIPHERY AND PUSH JUST TO THE NORTH AND EAST. A
WEAK OUTFLOW BOUNDARY IS CURRENTLY DRAPED ACROSS NE IL AND NW IN,
BUT LATEST OBSERVATIONS ARE SHOWING THIS BOUNDARY BECOMING MORE
DIFFUSE AS IT PROGRESSES EASTWARD. THIS TREND IS EXPECTED TO
CONTINUE WITH MINIMAL IMPACTS OVER CENTRAL INDIANA OUTSIDE OF A
SLIGHT INCREASE IN DIURNAL CUMULUS.
MOST CAMS DEPICT ADDITIONAL CONVECTIVE DEVELOPMENT LATER THIS
AFTERNOON OVER NORTHERN IN WHERE THE SHORTWAVE IS LOCATED, WITH A
GENERAL PROGRESSION E/NE DURING THE EVENING. WHILE PARAMETER SPACING
DOES NOT SUPPORT CONVECTIVE DEVELOPMENT OVER CENTRAL INDIANA, COLD
POOL DEVELOPMENT MAY ALLOW FOR DECAYING THUNDERSTORMS OR LIGHT
SHOWERS TO REACH NORTHERN CENTRAL INDIANA BETWEEN 7-10PM.
TEMPERATURES AND HEAT INDEX VALUES WILL BE HIGH ONCE AGAIN TODAY.
THERE IS SOME SIGNS OF MIXING THIS AFTERNOON WHICH MAY DROP DEW
POINTS A FEW DEGREES. A FEW OCCASIONAL GUSTS TO 18KT WILL ALSO BE
POSSIBLE AS THE PBL BECOMES MIXED THIS AFTERNOON.
CONDITIONS ARE EXPECTED TO BE VERY SIMILAR TOMORROW, WITH A NEAR
IDENTICAL SYNOPTIC SETUP. THE MAIN DIFFERENCE IS THE POSITION OF A
MID LEVEL BOUNDARY AND ADDITIONAL MOISTURE CONVERGENCE THROUGH THE
850-700MB LAYER. THIS MAY ALLOW FOR ENOUGH SATURATION IN THIS LAYER
FOR ISOLATED CONVECTIVE SHOWERS AND THUNDERSTORMS IN THE LATE
AFTERNOON AND EVENING. WHILE SEVERE WEATHER IS NOT EXPECTED, DCAPE
OF 900-1000 J/KG MAY SUPPORT A FEW DOWNBURSTS WITHIN THIS "POPCORN"
CONVECTION TO APPROACH SEVERE CRITERIA. WHERE THIS MID LEVEL
BOUNDARY SITUATES TOMORROW WILL ALSO BE THE PRIMARY LOCATION FOR
ADDITIONAL MCS DEVELOPMENT TOMORROW AFTERNOON THROUGH SATURDAY
MORNING. THIS IS CURRENTLY EXPECTED TO REMAIN NE OF CENTRAL INDIANA,
BUT THE AREA OF CONCERN WILL BE CLOSE ENOUGH TO WHERE A BRIEF
GLANCING FROM ORGANIZED THUNDERSTORMS WILL BE POSSIBLE OVER FAR NE
PORTIONS OF THE AREA.
THE MID LEVEL BOUNDARY WILL HAVE MORE SYNOPTIC SUPPORT SATURDAY,
WITH CONTINENTAL POLAR AIR ATTEMPTING TO MOVE INTO THE AREA FROM THE
NE LATE SATURDAY INTO SATURDAY NIGHT. THIS SHOULD GENERALLY INCREASE
CONVECTIVE ACTIVITY ACROSS THE AREA THOUGH MOISTURE CONVERGENCE AND
INCREASED WIND SHEAR. CONFIDENCE ON WHERE GREATEST THUNDERSTORM
COVERAGE WILL BE LOCATED IS LOW AT THIS TIME.
A BRIEF COOLDOWN IS LIKELY SUNDAY THROUGH MONDAY AS A DEEPENING
TROUGH OVER THE EAST COAST, PUSHES THE RIDGE WESTWARD. HIGH PRESSURE
IS EXPECTED TO BUILD BENEATH UPPER LEVEL CONFLUENCE LEADING TO A
DRYING TREND WITH HIGHS IN THE MID 80S WITH DEW POINTS IN THE UPPER
50S TO MID 60S. TOWARDS THE MIDDLE OF NEXT WEEK, THE RIDGE IS
EXPECTED TO BUILD BACK OVER THE REGION, WITH AN ADDITIONAL STRETCH
OF WELL ABOVE NORMAL TEMPERATURES AND HUMIDITY.
AVIATION (18Z TAF ISSUANCE)
ISSUED AT 1251 PM EDT THU SEP 3 2026
IMPACTS:
- WIND GUSTS AROUND 15-18KT POSSIBLE THIS AFTERNOON
DISCUSSION:
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. SOME CUMULUS WILL
POP UP THIS AFTERNOON, WITH PERHAPS SOME PASSING HIGH CLOUDS AT
TIMES.
ISOLATED CONVECTION CANNOT BE RULED OUT THIS AFTERNOON, MAINLY AT
KLAF. WILL WATCH THE SOUTHEAST PROGRESS OF AN OUTFLOW BOUNDARY
ACROSS NORTHEAST ILLINOIS THIS AFTERNOON, WHICH MIGHT ENHANCE THE
CHANCES FOR CONVECTION AT KLAF. FOR NOW FEEL ODDS ARE TOO LOW TO
MENTION.
ADDITIONAL ISOLATED TO SCATTERED CONVECTION MAY BE AROUND ON FRIDAY
AT KLAF/KIND, BUT AGAIN ODDS ARE TOO LOW TO MENTION.
IND WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 8 PM EDT FRIDAY FOR INZ021-028>031-035>049-
051>057-060>065-067>072.
AVIATION...50
DISCUSSION...UPDIKE
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