textproduct: Indianapolis

KEY MESSAGES

- Cooler and less humid weather expected through Tuesday

- Scattered showers and storms possible Wednesday evening into Thursday

- Dry weather returns for late week into the weekend

- Hotter and more humid air arriving Sunday into early next week

DISCUSSION (This Evening through Monday)

Issued at 138 PM EDT Mon Aug 24 2026

Dry and pleasant weather continues through midweek as central Indiana resides under the influence of high pressure. 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 through the forecast period. The expansion of upper level ridging by late weekend will bring the return of a hotter and more humid airmass to the Ohio Valley into early next week.

Rest of This Afternoon through Wednesday

Another beautiful late summer afternoon in progress as the region resides under high pressure. A scattered diurnal cu field has developed with generally light northwest winds. 17Z temperatures were in the 70s with comfortable humidity levels.

A superb next 48 hours through Wednesday afternoon is in store as the surface high drifts slowly through the region and remains the primary influence across the Ohio Valley. A brief period with increased mid and high clouds may graze the lower Wabash Valley this evening as a weak upper level wave passes through the lower Ohio Valley. Otherwise partly cloudy skies are expected through Wednesday with scattered cu developing each afternoon and diminishing near or just after sunset. With mainly clear skies and light winds...patchy fog will be likely late tonight and Tuesday morning in the favored areas in valleys and near streams.

As return flow develops from the southwest an increase in low level moisture will lead to an increase in cu coverage Wednesday afternoon in advance of a cold front approaching from the northwest. The cold front will approach in tandem with an upper level low rounding the crest of the ridge aloft to our west and dropping across the Great Lakes on Wednesday. Convection will generate to our north by late day in advance of the cold front.

Temps...low level thermals support highs largely in the low and mid 80s Tuesday and Wednesday with the warmer day on Wednesday courtesy of the advent of the southwesterly flow. Another night with lows in the 50s tonight will be followed by a moderating trend back into the 60s by midweek.

Wednesday Night through Monday

The aforementioned upper level low will become absorbed becoming absorbed by a broader long wave trough Wednesday into Thursday 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. Stronger convection that develops over lower Michigan and northern Illinois by late day Wednesday along the boundary may make it into far northern counties late Wednesday night in a weakened state before coverage drops off in the unfavorable predawn hours of Thursday with minimal instability available. The front will progress through the forecast area Thursday with scattered redevelopment over southern parts of the forecast area in the afternoon before clearing the area late day.

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. Return flow develops on Sunday as the high shifts off to the east... with an increase in temperatures and humidity levels by early next week as the ridge aloft to the west expands towards the Ohio Valley. The increase in moisture and instability will lead to an introduction of isolated to scattered mainly afternoon and evening convection. Highs in the upper 80s and lower 90s are expected by Sunday and Monday with max heat indices into the upper 90s.

AVIATION (00Z TAF Issuance)

Issued at 700 PM EDT Mon Aug 24 2026

Impacts:

- Fog possible at the outlying TAF sites late tonight into Tuesday morning, greatest confidence at KLAF

Discussion:

Mainly VFR conditions will continue across central Indiana into Tuesday as high pressure resides over the region. Scattered diurnal cu have mostly diminished across the state, with some cirrus drifting across central Indiana. A period of BKN150 is possible at KHUF and KBMG between 00-04Z. Fog will once again be possible at the outlying terminals late tonight and through daybreak Tuesday, with greatest confidence at KLAF. Greater upper level cloud cover at KHUF and KBMG early tonight may be enough to limit IFR or worse for at these sites.

N/NW winds remain at or below 10kts through the afternoon then become light and variable tonight. Winds will veer to southeast on Tuesday.

IND WATCHES/WARNINGS/ADVISORIES

None.