textproduct: Indianapolis

KEY MESSAGES

- Low chance for a brief shower today across southern Indiana with minimal thunder potential

- Breezy conditions expected today with wind gusts up to 20-25 mph

- Generally dry weather and a steady warming trend mid to late week

FORECAST UPDATE

Issued at 932 AM EDT Sun Jul 12 2026

Forecast is in good shape this morning. Lower clouds were across much of the southern third or so of the forecast area with some high clouds farther north. This general setup will continue through the day so just tweaked sky cover as needed.

With the upper trough just to the south of the area, can't rule out an isolated shower across mainly the far south. Made some minor adjustments to PoPs. Thunder cannot be ruled out, but odds are too low at this time to include a mention.

Forecast high temperatures look good so made no changes.

DISCUSSION (Today through Saturday)

Issued at 133 AM EDT Sun Jul 12 2026

Overview.

A weak, passing disturbance will bring a small chance for a light shower today across southern Indiana, along with breezy conditions. High pressure will then move into the region, bringing dry weather for the majority of the upcoming week. Temperatures will steadily climb each day, with highs in the 90s by mid-week.

Today Through Monday.

A weak mid-level shortwave and an associated surface trough will track across the southern Great Lakes today. While low-level moisture remains adequate, deeper saturation is lacking. Forecast soundings reveal a weak capping inversion above the boundary layer and poor mid-level lapse rates. Consequently, MLCAPE values are projected to remain minimal except for southern Indiana, which will significantly restrict updraft strength and prevent the deep vertical cloud growth required for sufficient glaciation to create lightning. Thunder potential is therefore too low to include in the explicit forecast, with coverage of any light convective showers remaining isolated to scattered. Breezy conditions will develop by mid-morning as diurnal heating deepens the boundary layer. Mixing up to approximately 850mb will tap into a 25 to 30 knot low-level wind field, translating to sustained surface winds of 12 to 18 mph with occasional gusts up to 25 mph from the northeast.

By tonight, the upper-level shortwave exits to the east, allowing surface high pressure and a much drier air mass to advect into central Indiana from the northwest. Strong large-scale subsidence and a drying column will rapidly clear out any lingering stratocumulus. Monday will feature pleasant, albeit warm conditions with clear skies, light winds, and seasonal high temperatures in the lower 80s as the core of the surface high settles over the Ohio Valley.

Tuesday Through Saturday.

Long-term guidance from the GFS and ECMWF, along with their respective ensemble suites, gives fairly high confidence in the broader synoptic pattern through mid-week with broad ridging across the Central Plains and broad troughing across the Eastern states. Early in the period, the forecast area will sit on the eastern periphery of a building central Plains ridge. By Wednesday and Thursday, this expansive upper-level ridge is modeled to expand eastward, with 500mb heights rising to around 592-594dam over Indiana. Strong subsidence associated with this feature will maintain dry conditions and suppress convective potential through at least Thursday.

A pronounced warming trend will accompany this building ridge as low- level flow shifts to the southwest, initiating strong warm air advection. Ensemble means indicate 850mb temperatures climbing from around 14C on Tuesday to near 21-23C by Friday. At the surface, this will manifest as a steady climb in afternoon maximum temperatures, starting in the mid-80s on Tuesday and reaching the low to mid-90s by Friday and Saturday. As the ridge axis shifts eastward, a return flow of Gulf moisture will push surface dewpoints back into the upper 60s to lower 70s. This combination of heat and humidity will likely produce peak heat index values approaching 100 at times mid to late week. The next potential breakdown of the ridge occurs late Friday into Saturday, as a northern stream shortwave flattens the upper flow and drags a weak, decaying frontal boundary toward the region, introducing low-end chances for showers and thunderstorms.

AVIATION (12Z TAF Issuance)

Issued at 540 AM EDT Sun Jul 12 2026

Impacts:

- Gusty NE winds from 18-22 kts this afternoon - MVFR to IFR cigs at BMG through 14Z

Discussion:

Dry weather expected through the TAF period with VFR conditions outside of a period of MVFR to IFR cigs through 14Z at BMG. Can't rule out a very short period of fog over the next hour or two, but with surface winds gradually increasing in speed, chances look minimal. After 14Z, the only impacts will be northeasterly wind gusts of 18-22kts which will come to an end by 00Z.

IND WATCHES/WARNINGS/ADVISORIES

None.