textproduct: Indianapolis

KEY MESSAGES

- Flood Watch from through Saturday afternoon for southern portions of central Indiana with 1 to 3 inches of rain possible

- Multiple rounds of showers and storms producing torrential rainfall and localized flooding expected through Saturday night

- Isolated severe storms possible across south central Indiana this afternoon and evening

- Hot and humid conditions expected for much of next week with multiple days in the 90s and heat indices over 100 degrees

DISCUSSION (This evening through Friday)

Issued at 319 PM EDT Fri Jun 26 2026

Today through Saturday Night

Quasi-zonal flow aloft above an east-west oriented baroclinic zone will allow a mid-level wave to progress into Indiana this evening. Surface low pressure associated with the wave will allow the baroclinic zone to lift northward as a warm front this afternoon. Numerous showers have developed today, initially from broad isentropic lift but some convective elements have also developed this afternoon. Low-level instability increases with time as the warm and buoyant air mass behind the front advects northward.

Though instability never becomes abundant, it likely becomes at least sufficient for continued scattered convective development into tonight. As the low approaches, model hodographs show some elongation and curvature in the 1-2km layer due to a strengthening low-level jet. Given a temperature profile that shows roughly moist adiabatic lapse rates, relatively shallow convection with minimal lightning is possible today. Despite this, some of these showers/storms may exhibit mesocyclone development due to the low- level shear profile. As such, isolated tornadoes are possible later today into tonight mainly across our southwest where better surface lapse rates are found. Strong wind gusts are also possible if activity can congeal into a line or cluster.

Our primary threat, however, is flooding and heavy rainfall. With deep moisture, moist adiabatic lapse rates, and a deep warm cloud layer, we can expect efficient rainfall processes today. Additionally, hodographs indicate that mature convection could become slow to stationary at times. Very heavy rainfall rates with prolonged duration across already moist ground may lead to a flooding and flash flooding threat through tonight. Additional showers and thunderstorms are possible on Saturday as the low pressure itself sits overhead, though activity will be more isolated in nature. The Flood Watch will be extended until 18z Saturday to account for this.

Convective coverage is a bit uncertain through tonight due to the relatively weak surface forcing as well as a mid-level wave that is weaker on recent model runs compared to earlier ones. Convective- allowing models have a difficult time with storm placement in such situation, and run to run consistency is likely to be quite low.

Sunday into Next Week

A few storms may linger into Sunday morning but the trend will be for the frontal boundary to lift north of the area Sunday as deep ridging expands into the Ohio Valley. This will serve as the transition point towards progressively hotter and more humid conditions that will last through much of next week as the core of the ridge peaks with heights at 596-597dam. Multiple days with highs in the 90s are anticipated with the highest heat indices of the summer so far rising into the 100s during the afternoons. Isolated late afternoon and evening convection may develop by late next week as the mid-level heights begin to fall back. As the upper ridge retrogrades to the southwest next weekend...will need to monitor for an increased risk for convective clusters riding along the periphery of the ridge impacting parts of the region.

AVIATION (18Z TAF Issuance)

Issued at 136 PM EDT Fri Jun 26 2026

Impacts:

- Numerous showers throughout the day and tonight with thunder possible as well this afternoon and early evening

- IFR conditions expected through tonight and into Saturday

Discussion:

Surface low pressure west of Indiana has lead to scattered showers and a few thunderstorms today. Showers and thunderstorms are expected to continue on and off this afternoon and into tonight. Periodic reductions in visibility are likely within heavier showers or storms. Rain chances diminish on Saturday but isolated showers are still expected to persist across central Indiana.

Ceilings have lowered into IFR territory for most of the region, with only LAF remaining in VFR. That is expected to change as the atmosphere continues to moisten. IFR conditions are expected to continue into the day on Saturday with periodic fluctuations into MVFR possible.

Winds will be primarily out of the southeast today ahead of the low. A period of light and variable winds is possible as the low pressure center arrives tonight. Winds may become southwesterly on its southern flank with the exact track deciding which terminals see a shift to southwesterly winds. Speeds look to remain under 10kt for the most part.

IND WATCHES/WARNINGS/ADVISORIES

Flood Watch through Saturday morning for INZ051>053-060>065- 067>072.