textproduct: Indianapolis

KEY MESSAGES

- Dry and cooler weather through Friday with warmer temperatures returning this weekend.

- Low chances for showers and storms and heat returns next week.

FORECAST UPDATE

Issued at 1022 PM EDT Wed Jul 22 2026

Latest observations show greater subsidence and near surface drying across the region. This along with clearing aloft north of I-70 is leading to greater confidence in efficient diurnal cooling tonight, especially over the Wabash River Valley. Areas near the Wabash River are likely to approach 50 by tomorrow morning. Due to this cooling and calmer winds near the valley, pockets of 1-3SM ground fog may develop in rural areas over NW central Indiana.

DISCUSSION (This evening through Wednesday)

Issued at 159 PM EDT Wed Jul 22 2026

Surface analysis this afternoon shows strong high pressure centered over the northern plains states with a surface ridge nosing SE to Indiana and Ohio. This was resulting in north to NE surface flow across Central Indiana and cooler temperatures compared to recent weather. Dew points were in the upper 40s and low 50s. GOES19 shows just some scattered and broken CU across the area. Aloft, ridging was found over the western CONUS, with NW flow spilling from western Canada into the Ohio Valley.

Tonight through Friday...

Relatively little change is expected during the period within the upper levels. Strong ridging is expected to continue to reside over the western CONUS, resulting lee side subsidence. This will result in the strong high pressure system that is over the northern plains to slowly work its way SE through Friday. Cooler easterly surface flow is expected to persist on Thursday, before further veering occurs on Friday with flow from the southeast. This will allow highs the next few days to return to near 80 degrees as the air mass modifies. Humidity will also remain somewhat pleasant as dew points remain in the 50s due to the east and southeast component of the winds.

Forecast soundings through the period continue to suggest a dry column with potential for afternoon CU as convective temperatures are reached. This will result in partly cloudy, pleasant days and mostly clear nights.

Saturday through Wednesday...

Dry weather with a warming trend is expected on Saturday and Sunday. That warming trend will continue into Monday through Wednesday, but small chances for thunderstorms will be present.

The ongoing, persistent pattern of strong ridging aloft over the western CONUS will continue trough Sunday. This will will keep the NW flow aloft in place over Indiana along with ongoing subsidence. The strong surface high will control our weather, but drift east and allow warmer, southerly flow as temperatures reach the 80s on Saturday and Near 90 on Sunday.

Models continue to show strong ridging in place west of Indiana on Monday through Wednesday, blocking much in the way of upper support. However within the lower levels, low pressure moving through the Great Lakes toward the middle Atlantic states suggest a cold front will drag across Indiana late Monday into Tuesday. Minimal change in air mass appears in play as there is little change in temperature in the wake of the front. Forecast soundings on Monday through Wednesday show plenty of CAPE available, but very warm mid levels near 13-14C at 700mb. Thus capping could be in play. For now, small pops for diurnal convection and with the frontal passage will be included on Monday afternoon through Wednesday afternoon, but confidence is low at this point. Highs will remain above normal early next week, in the low to middle 90s.

AVIATION (00Z TAF Issuance)

Issued at 659 PM EDT Wed Jul 22 2026

Impacts:

- Periodic ground fog possible at KLAF between 09-12Z

Discussion:

High pressure continues to build across the TAF sites leading to predominately VFR conditions through the TAF period. Efficient diurnal cooling could lead to localized areas of ground fog near KLAF tomorrow morning. Diurnal cu is expected to return tomorrow, with a SCT deck at 5000ft. Winds will lighten for the next 36 hours and veer towards easterly; expect sustained winds between 4-8kt.

IND WATCHES/WARNINGS/ADVISORIES

None.