textproduct: Indianapolis

KEY MESSAGES

- Hot and humid conditions expected for much of next week with multiple days in the 90s and heat indices over 100 degrees

FORECAST UPDATE

Issued at 1014 PM EDT Sat Jun 27 2026

Convection has been moving out of the area or weakening in typical diurnal fashion this evening, with primarily some weak cores remaining along the boundary from north Indy metro to east central Indiana - brief heavy downpours and slow motion are contributing to a minor hydrologic threat, but otherwise conditions are quieting down as areas that were deluged last night into today continue to see water issues improve.

With the boundary remaining in the region and plentiful low level moisture, expect additional development of fog and low stratus as we go through the night, with dense fog not out of the question, particularly in the rural and outlying areas and other favored regions.

Temperatures should fall only a little overnight as dewpoints remain in the upper 60s to low 70s across the area, and going forecast fits well with this.

DISCUSSION (This evening through Saturday)

Issued at 253 PM EDT Sat Jun 27 2026

Rest of This Afternoon through This Evening...

A surface front will meander across the southern half of the forecast area through tonight. An MCV was across southeast Missouri this afternoon, and this will move east across southern Indiana this evening.

Temperatures in the middle 70s to around 80 and dewpoints in the lower to middle 70s (across areas near and south of the front) have helped produce instability across the area.

The combination of the front and the MCV will produce scattered to numerous showers and thunderstorms, with the most coverage across the southern half of central Indiana, where the best instability and forcing will be. Will have some likely PoPs across this part of the area, with lower PoPs to the north.

With the instability and shear enhanced by the MCV, some severe storms are possible into this evening across the south.

The atmosphere remains quite moist south of the front. Current wind fields support slower storm motions. Convergence associated with the front and MCV will support bands of convection, which could result in training of storms. Thus, heavy rain remains a threat as well.

The far southwest forecast area had over 2 inches of rain in the 24 hours ending this morning, so extended the Flood Watch there until 00Z. Elsewhere across the south, localized flooding remains a threat but less rain had fallen there, so ended the watch.

Overnight through Sunday Night...

Without the support of the MCV, coverage of rain will greatly diminish overnight. Winds will be light, and moisture will linger. This will allow some fog to form once again for parts of the area.

On Sunday into the Sunday night, the surface front will return northeast as an upper ridge builds into the area. This may trigger an isolated shower or storm, so kept some slight chance PoPs for parts of the area during the day Sunday. For now, went dry Sunday night with the ridge building in. If the ridge is slower than expected, showers and storms riding around it Sunday night may clip the area.

Lows tonight will be in the mid 60s to lower 70s. With the ridge building in and more afternoon sunshine expected on Sunday, highs will be in the middle and upper 80s.

Monday and beyond...

An upper high/ridge will be the main influence across central Indiana during next week. For Monday through Wednesday, the high will be enough to keep the threat for rain below mentionable thresholds.

As early as Thursday, uncertainties in the location of the high/ridge are enough that isolated/scattered convection can't be ruled out. Confidence is low though in any rain Thursday into Friday as the ridging might still be strong enough to suppress convection. However, by next weekend it appears the ridge will be far enough way to allow convection to pop up from daily instability or from impulses riding around the ridge.

The main concern during this period will be the heat. Temperatures will peak in the lower to perhaps middle 90s, and dewpoints will be in the 70s. These will produce heat indices over 100 and perhaps even over 105 (especially in the very moist areas in the southwest). Blended guidance looks too high with dewpoints though, so will lower some.

Strict Heat Advisory criteria may not be met, but a long period of near Advisory criteria will likely require a multi-day Advisory at some point nonetheless. Will continue to message it will be hot regardless of headlines.

AVIATION (00Z TAF Issuance)

Issued at 723 PM EDT Sat Jun 27 2026

Impacts:

- A few lingering showers primarily early

- Widespread MVFR deteriorating to IFR/LIFR overnight into Sunday morning in fog and low stratus

Discussion:

Scattered convective activity has been steadily waning in the past few hours, and will carry some VCSH mention early to account for the last of it.

With the plentiful low level moisture and the boundary in the area, expect conditions to deteriorate again overnight, with widespread IFR or worse conditions late tonight into Sunday morning, before VFR eventually returns during the afternoon hours.

Winds will be well below 10KT throughout the period and occasionally calm to light and variable, particularly across the boundary, with all sites eventually becoming southerly during the day on Sunday.

IND WATCHES/WARNINGS/ADVISORIES

None.