textproduct: Indianapolis

KEY MESSAGES

- Scattered showers and storms, some severe, possible this evening.

- Dry weather returns for late week into the weekend.

- Hotter and more humid air arrives Sunday into early next week.

DISCUSSION (This evening through Wednesday)

Issued at 216 PM EDT Wed Aug 26 2026

Rest of This Afternoon and Tonight...

Weak lift well ahead of the surface cold front produced isolated showers across the northern forecast area earlier. These have since exited, but the lift continues to produce some clouds across the area. Can't rule out another isolated shower developing through mid-afternoon with this lift.

A line of showers and storms has developed in central Illinois this afternoon. This line is ahead of the surface cold front, which is farther to the northwest in Illinois. Instability continues to increase ahead of this line, with MLCAPE over 1500 J/kg. With some heating and moisture advection to go before the line arrives in central Indiana, the storms should become more numerous and intensify.

The line will move through the area from northwest to southeast late this afternoon through this evening. Decent shear will work with the aforementioned instability to keep a threat of some severe storms around. The primary threats will be damaging winds and large hail. However, isolated tornadoes cannot be ruled out, especially north where shear is best.

After midnight, only the southeast third or so will still see some scattered convection around. Instability will have waned by then, ending the severe threat. By 3 or 4 AM, convection should have exited the area.

Drier air will lag well behind the front, and winds will diminish overnight. This will set up the potential for some fog, especially south where rain will have fallen last.

Lows will generally be in the 60s.

Thursday...

The upper trough will linger across the area on Thursday. Low level moisture will remain. Any fog will lift early in the day, with a scattered to broken cumulus field developing. Some CAMs generate isolated convection Thursday afternoon with some weak forcing from the upper trough. This certainly cannot be ruled out, but for now feel odds are below mentioning in the forecast at this time.

Highs will be in the lower and middle 80s.

Friday through Monday...

An upper high will nudge its way into the area during this period. This will keep the area dry with increasingly warmer temperatures.

Initially dewpoints will be relatively low, but they will increase Sunday into Monday, making conditions more humid to go along with the elevated temperatures.

Highs in the lower to middle 80s on Friday will warm to the middle 80s to lower 90s by Sunday. On Monday, highs could reach the upper 80s to middle 90s. Heat indices may be near 100 degrees on Monday.

Tuesday and beyond...

Uncertainty increases in how much influence the upper high will continue to have across the area. For now, believe it will hang on, so will go dry the vast majority of the area on Tuesday. By Wednesday, it may lose enough influence for isolated convection to develop in the afternoon.

Heat will continue, with highs most likely from near 90 to the middle 90s. Heat indices near 100 would also then be likely.

AVIATION (18Z TAF Issuance)

Issued at 1259 PM EDT Wed Aug 26 2026

Impacts:

- Scattered convection mainly 21-04Z - Areas of MVFR fog overnight, with worse conditions possible

Discussion:

Scattered to broken clouds around 5000FT will continue this afternoon. Scattered convection will develop later this afternoon and move south across the sites through the evening.

Overnight, fog and some stratus is likely to develop, especially across the southern sites. Will go MVFR, but IFR and worse are possible. This fog will mix out to a scattered to broken cumulus field for Thursday.

Winds will become west this evening then northwest on Thursday.

IND WATCHES/WARNINGS/ADVISORIES

None.