textproduct: Indianapolis

KEY MESSAGES

- Peak heat indices nearing 100 degrees today

- A line of showers and t-storms expected this evening and additional storms possible late Monday into Tuesday

- Isolated strong to severe thunderstorms are possible this evening, damaging wind gusts are the primary threat

DISCUSSION (Today through Friday)

Issued at 310 AM EDT Sat Jul 18 2026

Active weather is expected again today as well as another day with highs near 90 and heat indices nearing 100. Can't rule out a few showers through the day, but the best chance of showers and storms will come this evening along a cold front pushing southward across central Indiana. Latest CAMs show that the timing will generally be about 6pm to a little after midnight before fully exiting to the south. Strong destabilization ahead of the approaching cold front along with modest enhancement of mid-upper level flow could promote isolated severe thunderstorms, primarily across northern portions of central Indiana. Forecast soundings depict around 20-30 kt of effective shear, strong instability with steep low-level lapse rates, and DCAPE values as high as 1000 to 1300 J/KG which support the threat. The primary convective hazard is damaging wind gusts. The severe hail threat will be largely limited by the linear storm mode.

Behind the front, surface high pressure will move in and bring slightly cooler and drier air. Unfortunately, smoke from Canadian wildfires could also return to the area for the start of the new week.

Models continue to show a shortwave bringing additional precipitation chances sometime late Monday through Tuesday. Behind this system, guidance has much cooler and drier air for the latter half of next week, with highs likely in the upper 70s to low 80s and overnight lows potentially dropping below 60.

AVIATION (06Z TAF Issuance)

Issued at 1258 AM EDT Sat Jul 18 2026

Impacts:

- Possible brief MVFR in BR later tonight - MVFR/worse possible after 20Z Saturday in stronger convection - Wind shift to northerly at end of TAF period

Discussion:

Expect mainly VFR conditions near central Indiana terminals through midday Saturday...with non-zero chances of MVFR from fog later tonight although confidence too low to include in TAF.

TSRA to return later Saturday with an west-east aligned cool front that will cross the region from north to south into the evening, with greatest chances for stronger winds/MVFR within 22Z-03Z.

Winds through dawn will be light and variable or most often from the southwest...with flow near 7KT at times at KIND. Westerly winds Saturday will increase to 8-13KT for most sites after 15Z, with gusts nearing 20KT at KIND/KLAF after 18Z.

IND WATCHES/WARNINGS/ADVISORIES

None.