textproduct: Indianapolis

KEY MESSAGES

- Scattered to numerous showers and storms will be around at times today and tonight.

- An isolated severe storm with damaging winds is possible this afternoon afternoon. Locally heavy rain remains a threat.

- Rain chances continue early this week, then dry weather should return. Temperatures will be much cooler after today.

DISCUSSION (Today through Saturday)

Issued at 248 AM EDT Sun Sep 20 2026

Early This Morning...

Some upper energy along with the old surface front were generating some scattered showers across the northeastern half of the forecast area.

As an associated surface low across western Illinois moves east and the initial upper energy departs, the scattered showers should push east and north. Most of central Indiana should be dry by 12Z.

Today and Tonight...

Another upper wave will move east and provide forcing this afternoon. Meanwhile, the surface low will move southeast across the area.

With little or weak forcing across the area this morning, will only have some low PoPs across the far north where the front will start out.

During the afternoon, as the surface low moves through, forcing will increase. The low will drag the front south. Thus, expect scattered to numerous showers and thunderstorms to develop.

Interestingly, some drier air will get advected into the southern forecast area ahead of the surface low. This may limit convection development there until the surface front gets closer toward 00Z.

CAMs show a variety of solutions, while other guidance focuses rain north, near and behind the front. Given all the above, will go likely PoPs in the far north mid to late afternoon, tapering to slight chance in the far south. Confidence isn't great as mesoscale influences as well as the aforementioned dry air could change things.

If enough instability builds, cannot rule out an isolated severe storm with damaging winds ahead of the front. Locally heavy rain remains a threat with precipitable water values near 2 inches.

Rain chances will continue tonight as the front continues to trek south and additional upper energy moves through. Overall though forcing doesn't look great, so will keep PoPs no higher than chance category.

A strong temperature gradient will exist again today as the front moves south. Trimmed blended guidance far north given the expected location of the front and clouds/rain chances. Went near 80 far north to the lower 90s south.

Monday and Tuesday...

Upper waves on Monday followed by an approaching upper low on Tuesday will keep chances for rain around. The hot air will finally be south of the area. Highs will be in the upper 60s to near 80 on Monday with only mid 60s to lower 70s Tuesday.

Wednesday and beyond...

The far east may see an isolated shower Wednesday as the upper low exits. Otherwise, high pressure will provide dry weather into next weekend. Temperatures will start out below normal, but they will return to closer to normal next weekend.

AVIATION (06Z TAF Issuance)

Issued at 132 AM EDT Sun Sep 20 2026

Impacts:

- Scattered showers around early. Additional scattered convection mainly this afternoon and evening. - MVFR conditions along with a wind shift move north to south later this afternoon into the evening

Discussion:

Scattered showers at KIND/KLAF will diminish overnight as forcing diminishes. A low pressure system and cold front will trigger more scattered convection mainly this afternoon and evening, but much uncertainty remains on how this plays out. Will just use a VCSH mention for now, but thunder is certainty possible.

Behind the front, winds will become north and northeast, and ceilings will drop into MVFR a while after the wind shift. At KLAF, some mist may accompany the lower clouds.

IND WATCHES/WARNINGS/ADVISORIES

None.