textproduct: Indianapolis

KEY MESSAGES

- Numerous showers and isolated thunderstorms continue tonight

- Flood Watch in effect through 8 AM EDT Sunday for much of central IN

- Rain chances will persist through the weekend with additional chances at times next week

FORECAST UPDATE

Issued at 943 PM EDT Sat Aug 1 2026

Severe convection has exited central Indiana to the east this evening, moving into areas where better instability and shear remain. Coverage of showers has diminished, especially south.

With the upper and surface lows still meandering across central Indiana during the night, showers will continue at times. The most coverage of the showers will be across the northern half of the forecast area, north of the surface low. Will continue with likely or higher PoPs there, with lower PoPs to the south.

Atmospheric moisture content remains high, with precipitable water values approaching 2 inches across the north. Efficient rainfall processes will persist in showers through the night. Weak frontogenetical forcing may aid in producing heavier bands of rain, again mainly north.

Numerous areas across the forecast area received multiple inches of rain today, so any additional heavy rain will cause more issues. Will continue the Flood Watch as is. Several Areal Flood Warnings will continue during much of the night with flooding from the earlier heavy rain persisting.

Isolated thunderstorms will remain possible with the weak instability, but severe storms are not expected.

Forecast low temperatures look good so made no changes. Adjusted hourly forecasts as needed based on latest observations. Cloud cover should help keep much fog from forming in the moist atmosphere.

DISCUSSION (This evening through Saturday)

Issued at 147 PM EDT Sat Aug 1 2026

This afternoon through tonight...

Current KIND radar imagery depicts increasing coverage of showers across central IN after a brief lull in precipitation.Increasing large scale ascent from an approaching mid-upper level vort max centered over IL combined with low-level theta-e advection ahead of an associated low pressure system will continue to promote additional convective development. Expect widespread showers this afternoon along with scattered thunderstorms once sufficient destabilization occurs.

Efficient rainfall rates and repeated rounds of showers/storms from the slow moving system could result in localized flash flooding through daybreak Sunday. An associated warm front lifting north is expected to stall near or just north of the I-70 corridor into the evening hours which may also increase the threat for flooding as slow moving storms could train over the same areas. A FLOOD WATCH is now in effect for much of the forecast area through 8 AM EDT Sunday with rainfall amounts of 1 to 3 inches expected. Locally higher amounts of 4+ inches are possible.

Modest to moderate destabilization later this afternoon combined with sufficient effective wind shear supports the threat for isolated severe thunderstorms, mainly for E/SE portions of central Indiana. Forecast soundings depict gradually steepening lapse rates and mid-level dry air contributing to DCAPE values around 900 to 1100 J/KG which may result in isolated damaging wind gusts. Low- level veering hodographs from the warm front lifting north could also promote an isolated tornado threat.

Some uncertainty still remains regarding the overall severe threat. Mesoscale details such as how far north the warm front moves and the degree of destabilization or low-level buoyancy later this afternoon will ultimately determine the severe weather risk. The flooding threat is the greatest concern, but isolated severe weather remains possible over mainly E/SE portions of central Indiana. If any severe weather occurs it would likely be from around 2 to 9PM EDT before instability weakens.

Sunday through Monday...

The aforementioned low pressure system is expected to still be over the area on Sunday as it slowly crawls southeastward. Broad cyclonic flow and lingering moisture will promote scattered or numerous showers. A low flooding threat may linger into Sunday, but very limited instability and weaker forcing should lead to lower rainfall rates. Look for coverage of showers to decrease late in the day into Sunday night with the system gradually departing.

Surface high pressure building in Monday will provide mostly quiet weather. However, lingering moisture and daytime heating may support isolated showers or a stray storm across far southeastern counties late in the day.

Tuesday onward...

Long range guidance generally shows the aforementioned system becoming cutoff once again and retrograding towards the Ohio Valley Tuesday into Wednesday. Deeper moisture advecting back into the southeast half of central Indiana along with weak dynamics from the system and diurnal heating keeps low chances for precipitation in the forecast, mainly during the afternoon or evening. Multiple embedded shortwaves traversing the region Thursday through end of the week will promote additional convective chances. Exact details remain uncertain at this time due to diverging model solutions.

AVIATION (00Z TAF Issuance)

Issued at 715 PM EDT Sat Aug 1 2026

Impacts:

- At most, MVFR ceilings through period, down to IFR and even LIFR at times tonight into the morning hours

- SHRA much of the time, though TSRA is becoming less likely

Discussion:

A surface low continues to stimulate widespread MVFR to IFR ceilings across central Indiana, with winds varying as the low itself crosses through regional terminals. Earlier TSRA is now east of the TAF sites, with showers returning at KIND and KLAF. Areas to the south are seeing more intermittent showers, with fewer visibility impacts.

Conditions will slowly degrade over the next few hours as the surface low shifts east and sunset occurs, which will result in IFR conditions (with instances of LIFR CIGs) tonight. The low marches further east tomorrow, which combined with diurnal heating will improve flight categories to VFR through the mid to late afternoon. Additional degradations are possible after 00Z, but will be more scattered in nature.

IND WATCHES/WARNINGS/ADVISORIES

Flood Watch until 8 AM EDT Sunday for INZ021-028>031-035>049- 051>057-062>065.