textproduct: Indianapolis

KEY MESSAGES

- Severe storms possible Tuesday afternoon and evening with damaging winds the primary threat

- Heavy rain and some flooding are possible into the evening and again Tuesday

- Highs in the 80s Tuesday

- Storms will end Wednesday as the front shifts south, but unsettled weather likely returns late this week into the holiday weekend

FORECAST UPDATE

Issued at 1005 PM EDT Mon May 18 2026

Expect mostly quiet weather overnight as the disturbance which brought active weather to central IN earlier today continues to shift east. Current KIND radar imagery shows lingering light precipitation mainly across far south-central IN which should move out over the next few hours. A few additional showers or an isolated thunderstorm may develop late tonight, mainly across northern counties near a weak boundary. Southerly winds remaining elevated will help limit the potential for fog despite recent heavy rainfall. Areal Flood Warnings and Flood Advisories remain in effect for portions of central Indiana as water continues to slowly recede. Do not drive through flooded roadways.

DISCUSSION (This evening through Monday)

Issued at 246 PM EDT Mon May 18 2026

Rest of This Afternoon and Tonight...

Please see the latest Mesoscale Discussion section for details on the current convective situation.

Thunderstorms will continue to move east this afternoon, with faster movement across the northern forecast area. To the south, the cold pool is having a harder time moving south, and showers and storms continue to develop as the low level jet impinges upon it.

Later this afternoon into early evening, some additional upper energy will produce additional showers and thunderstorms. Will continue high PoPs this afternoon into early evening, especially southwest where the regeneration of storms will continue along the cold pool boundary.

This regeneration of showers and storms in the southwest may lead to flooding, so will continue the Flood Watch. May have to adjust the location of the watch if the area of regeneration shifts.

The main threat for severe will be out ahead of the initial line of storms into the afternoon. Damaging winds will be the primary threat.

Coverage of rain will diminish this evening into the overnight as most forcing exits. However, some weak upper energy may keep the threat for a few showers around northwest.

Went cooler than guidance for lows given the rain cooled air.

Tuesday...

Uncertainty remains on how convection will develop on Tuesday with the surface cold front moving in. There may be cloud cover in the morning from upstream convection which would help limit instability. Some CAMs limit coverage to the southeast forecast area, while larger scale models bring rain to all areas Tuesday into Tuesday night.

Given the strength of the front and the plentiful moisture, went likely PoPs all areas at some point Tuesday afternoon and evening. The severe threat will depend on how well the instability is able to build. Damaging winds will be the primary severe threat. Given today's rainfall and the plentiful moisture Tuesday, heavy rain and flooding will remain a threat for Tuesday as well.

Highs on Tuesday could reach the middle and upper 80s if morning clouds are thin enough and rain holds off long enough.

Wednesday and Thursday...

Some rain may linger Wednesday morning in the south, so kept some low PoPs there. There remains some uncertainty on how far south the front will then settle and thus how fast it returns north. GFS seems aggressive with returning rain on Thursday, so will keep most of the area dry through the daytime Thursday. Rain chances begin to spread north Thursday night.

Much cooler air will return for this period with highs in the upper 60s to around 70 and lows in the middle 40s to lower 50s.

Friday through Memorial Day...

A northern stream upper trough will move into the central USA while a southern stream smaller upper wave moves into the area. These will help bring the surface front northward back into the area into Saturday. Decent moisture will move back north with it, so will have likely or higher PoPs Friday into Friday night.

Upper energy may interact with the lingering front to produce some rain on Saturday, so will keep PoPs around.

A couple of upper troughs will bring more rain chances Sunday into Memorial Day. There remains some decent uncertainty on timing and strength, so will broadbrush PoPs and keep them under the likely category until uncertainty improves.

With the surface front having lifted north, warmer air will return, with perhaps 80s again by the latter half of the holiday weekend. However, confidence isn't high in these given the uncertainty in rain coverage Sunday into Memorial Day.

AVIATION (06Z TAF Issuance)

Issued at 128 AM EDT Tue May 19 2026

Impacts:

- Wind gusts Tuesday 20-27KT

- Showers and thunderstorms possible late this afternoon into this evening

Discussion:

Yesterday's convective activity has diminished and cleared the area, and quiet weather is expected most of the rest of the night. Cloud cover should prevent significant fog, though a few patchy areas cannot be ruled out given the ample rainfall.

Winds will strengthen as mixing ramps up Tuesday morning, with gusts of 20-27KT likely through the day, generally from 210-230 degrees.

Showers and thunderstorms will be possible late in the day as a cold front approaches and passes through the area. Winds with frontal passage will veer to westerly and northwesterly late in the period, with gusts ending in typical diurnal fashion this evening.

IND WATCHES/WARNINGS/ADVISORIES

None.