textproduct: Indianapolis

KEY MESSAGES

- Heat Advisory in effect for all of central Indiana through late today with peak afternoon heat index values up to 108 degrees

- Isolated to scattered thunderstorms will be possible at times late today through the weekend.

DISCUSSION (Today through Thursday)

Issued at 316 AM EDT Fri Sep 4 2026

Ridging continues for most of central Indiana as well as heat and humidity. A heat advisory remains in effect for today as highs will remain in the 90s and may even see 100 degrees in our far SW. Heat indices today will again reach near to above 105. Tomorrow should be a few degrees cooler at least with more of a temperature gradient across the forecast area but only moderate confidence on exact highs as it will largely depend on how convection plays out today.

A weak boundary sits along the periphery of the ridge, north and east of the forecast area, while troughing to the NE continues to try to nudge its way in. This is leading to uncertainty in PoPs over the coming days as it is still unclear when the high pressure will finally let up enough. CAMs continue to hold off on the boundary and associated precipitation from creeping in today, but isolated showers and storms are still probable periodically throughout the day. Chances for isolated to scattered storms should see better chances as we get into Saturday, assuming the boundary is finally able to dip further SE. Still can't rule out a few strong to severe storms should storms actually form within central Indiana, but this threat remains conditions.

Holding onto the upper high further retrograding late this weekend into early next week, with which a backdoor cold front should finally bring some relief to the heat and humidity, at least for a couple of days. By midweek, the upper ridging is expected to return and with it a brief warming trend. Models are showing that the upper pattern should become more zonal as next week progresses which should allow the heat to relax again. Still watching trends for additional precipitation chances sometime mid to late next week.

AVIATION (12Z TAF Issuance)

Issued at 651 AM EDT Fri Sep 4 2026

Impacts:

- Isolated convection possible Friday PM, mainly near KIND/KLAF but low confidence

Discussion:

VFR conditions are expected through the TAF period. Hot and humid subtropical ridge will shift its center from the SE CONUS to the Plains which will allow a small northern disturbance to possibly drag isolated convection across the region at times through the TAF period. So far confidence is too low in TSRA for any mention in TAFs past VCSH.

Overall light winds this morning may maintain subtle organized southerly flow. Winds this afternoon outside of any convection will be from 240-280 degrees, nearing 7KT/10KT thresholds, with most gusts weaker than prior days.

IND WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 8 PM EDT this evening for INZ021-028>031- 035>049-051>057-060>065-067>072.