textproduct: Indianapolis

KEY MESSAGES

- Cooler temperatures through Tuesday night with highs in the low- mid 70s and lows in the 50s

- Showers and thunderstorms possible Tuesday, marginal risk of severe weather.

- Showers and thunderstorms likely on Wednesday with a much greater risk of severe weather.

..ENHANCED SEVERE WEATHER THREAT ON WEDNESDAY

As of this writing, SPC has placed much of central Indiana within an Enhanced area for severe weather on Wednesday. This is due to the models suggesting a second and stronger upper wave passing within the flow aloft. The wave is expected to trigger a deepening surface low, expected to track across IL and into the Great Lakes. This will place Indiana within the warm sector as the forcing passes along with an associated cold front late Wednesday night. An unusual feature for this time of year is the strong surface low allows for the development of a very strong LLJ across northern Indiana on Wednesday night, in excess of 60 knts. Forecast soundings show favorable CAPE in excess of 1700 J/KG in a highly sheared environment. Supercell Composites appear to be high during the mid to late afternoon and helicity appears to be favorable for tornadoes. Should all these signals remain in the next few days, Wednesday will be a significant weather day with tornadoes quite possible, especially in western Central Indiana. A caveat...convective remnants of an MCS over WI could impact cloud cover, particularly across northern parts of Indiana during the morning hours. This could impact afternoon instability. Nonetheless, the day looks like morning clouds, possible precipitation across northern Indiana, followed by convective initiation after 600PM in IL with propagation across Central Indiana through 200 AM. It is this evening window that will be most concerning for severe weather potential. Continue to stay weather aware in the coming days and be ready to activate your preparedness plan on Wednesday.

Thursday Through Monday.

By Thursday morning, the convective system and its associated deep- layer forcing will have advanced well into the upper Ohio Valley, leaving central Indiana embedded within a regime of strong post- frontal subsidence. The primary synoptic driver will be an expanding 1022 mb surface high pressure sliding southeastward out of the northern Plains. This area of high pressure and and dry air advection aloft will allow for skies to slowly clear. Going into Friday, continued CAA will help keep highs on Thursday into Friday in the mid to upper 70s across the northern counties and the lower 80s further south.

Given the substantial rainfall accumulated prior to Thursday morning, hydrologic impacts will become a greater concern going into the weekend. MMEFS guidance shows an elevated probability of river flooding, especially on the Wabash River. The guidance indicate a 60 to 80 percent chance of several crests reaching minor flood stage with river levels similar to potentially slightly higher than the flooding that occurred earlier this week.

Ideal radiational cooling and dry surface air on Friday and Saturday nights will allow overnight minimums to drop into the low to mid- 50s. By Sunday and Monday, the high pressure center will slowly drift toward the mid-Atlantic, causing low-level winds to shift to a more southerly component. This will kick off a gradual warming trend allowing afternoon highs to return to near-seasonal norms in the lower to mid-80s. While the operational consensus strongly supports this prolonged dry spell, a notable alternate scenario is present within a cluster of the European ensemble members. This subset of guidance suggests that a weak, secondary shortwave dropping down the eastern edge of a larger Canadian longwave trough could slide slightly further west than currently projected around Saturday night. If this deeper track verifies, rain chances will gradually begin to increase as early as Sunday night, but confidence remains low due to the aforementioned model differences.

AVIATION (18Z TAF Issuance)

Issued at 1240 PM EDT Mon Jun 15 2026

Impacts:

- VFR this TAF Period - Chance of thunderstorms Tuesday afternoon after 17z.

Discussion:

VFR conditions are expected through the period.

A surface ridge of high pressure was over Indiana, extending west from the central plains states. GOES19 shows sct-bkn CU across Central Indiana.

The surface high will maintain control of the weather this afternoon providing fair weather. As heating is lost this afternoon, CU will dissipate leading to unlimited ceilings overnight.

On Tuesday, a quick moving upper level weather disturbance will push toward Indiana. HRRR suggests a line of shower and storm development pushing across the TAF sites within the 16Z-22Z time frame. For now, have included a tempo group to account for that. Brief MVFR conditions are possible with any TSRA that strikes a TAF site.

IND WATCHES/WARNINGS/ADVISORIES

None.