textproduct: Indianapolis

KEY MESSAGES

- Isolated showers cannot be ruled out across northeastern counties late this afternoon into the evening

- Cooler and less humid weather expected through Tuesday

- Scattered showers and storms possible Wednesday evening into Thursday

DISCUSSION (This Evening through Sunday)

Issued at 142 PM EDT Sun Aug 23 2026

A progressively drier trend than the last couple weeks continues through much of the upcoming week as high pressure resides over the Ohio Valley for much of the forecast period. Deep upper level ridging will remain tethered for the next several days over the Intermountain West with a largely dry northwest flow over the region. The passage of a cold front late Wednesday into Thursday will present the primary convective risk until the latter part of next weekend.

Rest of This Afternoon through Tuesday Night

Diurnal cu development has increased with heating as temperatures warm through the 70s. Satellite shows more enhanced cu over the Great Lakes extending south into northern Indiana with a few showers near KFWA in response to the double barreled upper low pinwheeling over Ontario. A piece of energy dropping south on the back side of upper low will pivot across lower Michigan and Lake Erie later this afternoon into the evening and may provide just enough lift in tandem with the steep lapse rates and weakly unstable airmass present to generate stray showers over northeast counties into the early evening. This would be similar to what took place Saturday evening but with lower instability levels limiting the coverage and intensity of any showers. Most will remain dry but any location that gets under a small shower may see a very quick downpour.

High pressure will fully settle over the Ohio Valley tonight through much of the first half of the week with quiet weather and abundant sunshine anticipated. Low level thermals support cooler than normal temperatures through Tuesday with highs generally ranging from the mid 70s northeast to the lower 80s in the lower Wabash Valley. Lows will be very comfortable in the 50s the next two nights before return flow Tuesday night nudges lows back up into the low to mid 60s for most of the forecast area. Really cannot ask for a better next 60 hours or so for the region...much deserved after the very active and wet last few weeks.

Wednesday through Sunday

A weakening upper level low riding overtop of the western ridge will drop into the upper Midwest early Wednesday before becoming absorbed by a broader long wave trough that will amplify across the eastern half of the country for late week. Low pressure and an associated cold front running in tandem with the upper wave will track across the Ohio Valley Wednesday night and early Thursday in a progressively weakened condition as stronger forcing aloft is lost. There will be enough moisture and instability along and immediately ahead of the frontal boundary for scattered convection with the front clearing the forecast area during the day Thursday.

High pressure will reestablish in the wake of the frontal passage drifting slowly east through the Great Lakes into Saturday. This bring another multi day stretch of dry weather with seasonable temperatures as highs will focus largely in the low to mid 80s. The ridge will flatten to the west over the weekend opening the possibility for convection to impact the region by late weekend into early next week as multiple waves ride along in the predominantly zonal flow aloft. Temperatures will also rise back into the mid and upper 80s by the end of the forecast period with an uptick in humidity levels.

AVIATION (18Z TAF Issuance)

Issued at 142 PM EDT Sun Aug 23 2026

Impacts:

- Patchy fog possible at the outlying terminals after 08Z tonight

Discussion:

Mainly VFR conditions to continue across central Indiana through the period as surface high pressure remains in control. Expect northwest flow through through the evening. Winds become light and variable tonight before picking up again tomorrow afternoon.

Fog/BR is possible at the outlying sites again after 08Z tonight. Scattered diurnal cu is will continue to this evening.

IND WATCHES/WARNINGS/ADVISORIES

None.