textproduct: Indianapolis

KEY MESSAGES

- Isolated showers cannot be ruled out across far northeastern counties late this afternoon into the evening

- Cooler and less humid weather expected through Tuesday.

- The next best chance for rain will be Wednesday evening through Thursday.

FORECAST UPDATE

Issued at 1006 AM EDT Sun Aug 23 2026

Minimal adjustments were needed to the forecast, mainly to temps to better match current observations. Today still looks mostly dry with afternoon highs reaching the mid 70s in our NE and into the low 80s in the SW. A few isolated showers are possible this afternoon into evening in the NE like was seen last evening.

DISCUSSION (Today through Saturday)

Issued at 304 AM EDT Sun Aug 23 2026

Today through Tuesday night...

Mostly quiet weather conditions are expected early in the period with surface high pressure across the region. Aloft, upper troughing to start the period will help keep temperatures cooler. Upper troughing begins to shift east with ridging building in early in the work week, but seasonably cool temperatures will persist as surface flow remains northwesterly. A few showers cannot be ruled out Sunday afternoon or evening across northeast portions of central Indiana due to a weak boundary pushing through.

Confidence in showers developing is low as forcing and moisture will be marginal at best. However, a few CAMs suggest the potential for isolated convection to develop so low POPs were included for far northeastern counties. Light winds and mostly clear skies are expected to promote patchy fog development both early this morning and again late tonight into early Monday morning. Any fog that develops should quickly mix out after daybreak. Surface high pressure begins to shift east Tuesday, but surface riding will continue to promote quiet weather.

Wednesday through Saturday...

Long range guidance depicts multiple upper level waves traversing the region towards mid-late week returning precipitation chance to the forecast. The first wave approaches late Wednesday bringing a frontal boundary into the region. Modest forcing and sufficient moisture advection ahead of the disturbance supports the potential for scattered showers and thunderstorms.

Low chances for convection linger into Thursday, but this will be heavily dependent on the location of the aforementioned boundary. At this time, guidance suggest lingering low-level moisture will be in place across central Indiana supporting the potential for diurnal convection. If the front moves through earlier in the day, expect mostly dry conditions. Long range guidance generally suggest surface high pressure builds back in late week providing quiet weather. Look for temperatures to remain slightly below normal.

AVIATION (12Z TAF Issuance)

Issued at 701 AM EDT Sun Aug 23 2026

Impacts:

- Fog possible at the outlying terminals after 07-08Z tonight

Discussion:

Mainly VFR conditions to continue across central Indiana through the period as surface high pressure remains in control. Expect light northwest flow through 14Z before increasing to around 07-12 kt later in the day. Winds become light and variable tonight.

Fog/BR is possible at the outlying sites after 07-08Z tonight. Some scattered diurnal cu is expected to develop today.

IND WATCHES/WARNINGS/ADVISORIES

None.