textproduct: Indianapolis

KEY MESSAGES

- Showers and thunderstorms likely late Saturday, with severe weather possible Saturday night into Sunday.

- Much cooler temperatures on Monday with highs in the 70s.

- Unsettled weather with near normal temperatures next Tues-Thurs.

DISCUSSION (Today through Friday)

Issued at 255 AM EDT Sat Jun 13 2026

Synoptic analysis shows broad troughing over Canada with a roughly zonal jet stream crossing the northern CONUS. Surface high pressure currently resides over Indiana, with broad subsidence leading to clear skies and light winds.

High pressure slides eastward today, allowing surface winds to become southerly. This should promote moisture advection northward, with dew points climbing gradually throughout the afternoon and evening hours.

To the west, a cluster of strong thunderstorms is located over southern kansas and northern Oklahoma. Guidance shows an MCV emerging from this cluster, which is expected to generate a secondary round of convection across Missouri this afternoon. A few showers and perhaps a thunderstorm may develop over Illinois and extend into central Indiana, associated with the leading edge of deeper moisture advection. Guidance is in poor agreement regarding this initial round of showers or storms, so probability of occurrence is rather low. Slight to chance PoPs will be carried during the afternoon hours mainly across western Indiana.

A more potent vort max embedded within the zonal flow to our north arrives late Saturday into Sunday. Combined with the MCV, convection upstream over Missouri and into Iowa likely consolidates into a line which then propagates southeastward. Should an MCS develop, it will be aided by rich moisture advection ahead of it and easterly deep layer shear to promote cold pool updraft balance. Shear diminishes with eastward extent, however, so the likelihood of a strong MCS is greater across western portions of the area. The MCS could just as well pass southwest of our forecast area with little impacts.

Guidance has been struggling to resolve this due to the relatively modest forcing and lack of a distinct triggering mechanism (like a strong cold front). As such, convective evolution depends on cold pool dynamics which numerical models have difficulty resolving. As such, the predictability of convective evolution into Indiana will remain low even within the very near term.

We will maintain chance to likely PoPs across the area, as even with an MCS or lack thereof it still looks like showers associated with the vort max are probable Saturday night into Sunday morning. In terms of severe potential, upscale growth into a southeastward propagating MCS will lead to damaging wind gusts becoming the primary hazard. Large hail is possible with discrete convection, which is more probably during the afternoon over Illinois but could sneak into western Indiana.

Low clouds and dreary conditions persist into Sunday, with scattered showers and perhaps additional thunderstorms, until the system's cold front arrives. This front, which lags behind the best forcing and moisture, could pass through without much fanfare Sunday afternoon. Some models depict a few showers and thunderstorms along the front itself though these are outliers as of the 06z model suite.

Once the front has passed, expect clearing skies as high pressure returns. Multiple days of cooler-than-normal temperatures are likely as broad troughing remains aloft. Active weather may return midweek as embedded waves pivot around the larger-scale trough. These waves are difficult for guidance to resolve this far out, but there seems to be a loose signal pointing at the Tuesday evening to late Thursday timeframe.

AVIATION (12Z TAF Issuance)

Issued at 631 AM EDT Sat Jun 13 2026

Impacts:

- Low chance for showers and isolated storms this afternoon - Increasing chance of showers/storms after 06z - MVFR ceilings likely after 06z Sunday, IFR possible by daybreak - Wind shift to northwesterly around 14z Sunday

Discussion:

VFR conditions are expected today, with a low chance of isolated showers after 21z as a mid-level system and cold front approach from the west.

Shower chances, as well as thunderstorms, increase after about 06z Sunday. Abundant low-level moisture advection should promote widespread MVFR ceilings towards the end of the TAF period. There is potential for IFR ceilings by daybreak Sunday.

Winds remain light out of the south or south-southwest today, increasing to about 10kt this afternoon. Winds diminish after 00z. Thunderstorms, should they occur, may produce brief variable wind gusts over 30kt. As of this update, the probability of occurrence is too low to include in the TAFs.

The aforementioned cold front arrives around 14z Sunday, give or take an hour as there is still some uncertainty within high-resolution model guidance. A wind shift to northwesterly is expected once the front passes through.

IND WATCHES/WARNINGS/ADVISORIES

None.