textproduct: Indianapolis

KEY MESSAGES

- Scattered showers/t-storms through tonight. Isolated flooding possible

- Humid and very warm this week...daily rain chances continue through Friday...readings near 90F on Wednesday and Thursday

- Slightly cooler weather for the weekend with lower rain chances

FORECAST UPDATE

Issued at 942 PM EDT Mon Jun 8 2026

Only minor adjustments made to the forecast with conditions generally evolving as expected. Main focus for the update was to fine-tune hourly POPs through tonight with much of central Indiana currently dry and latest Hi-Res model guidance hinting at less coverage during the overnight hours. This is mainly due to a warming trend in the 800mb to 700mb which is also showing up on the last few ACARs soundings over IND. That being said, the upper level flow is becoming more westerly which will allow the convection across eastern Illinois to take a more easterly direction. With all that in mind, will focus POPs higher across the Wabash Valley over the next few hours with lower overall coverage further east later in the night.

Main threat with the overnight convection will be isolated flooding with the generally slow storm motion and pockets of very saturated ground across portions of western Indiana.

DISCUSSION (This evening through Monday)

Issued at 209 PM EDT Mon Jun 8 2026

Surface analysis this afternoon shows warm and humid southerly flow in place across Central Indiana. This was due to low pressure over western KS, and strong high pressure found over Upstate NY. Water vapor shows an upper trough over the middle Mississippi river valley. A tropical plume of moisture was found streaming northward ahead of the trough across TN/KY and IN. Showers and storms were found across IL and southern Indiana, pushing northeast.

Tonight and Tuesday...

Models suggest the upper trough to the west will continue to progress northeast toward Indiana, passing mainly during the overnight hours. Forecast soundings show a deeply saturated column this evening and overnight as the moderate forcing arrives with a very moist air mass in place. Given the high pwats over 1.8 inches, heavy rain will be possible. Diurnal heating will add to thunderstorm coverage this afternoon, but will be diminished by late evening as heating is lost. Still Central Indiana should expect showers overnight as the best forcing from the upper trough axis arrives. Very high pops will be use.

As the upper trough exits on Tuesday, forecast soundings begin a top down drying. But lower level moisture will remain. Although this will end the limit the precipitation fop the rest of the day, chances will return during the afternoon due to the lack of change of airmass. Forecast soundings on Tuesday afternoon suggest steep lapse rates with plentiful CAPE and attainable convective temperatures. Thus chances for more diurnal showers and storms late in the afternoon and into the evening will be needed. Highs in the middle 80s will be expected.

Wednesday...Hot and humid weather will be expected as southerly flow will continue to allow humid gulf air to reside across central Indiana. A passing ridge aloft will provide subsidence and moderate pressure gradient will provide good mixing on southwest winds. This should allow high to reach the upper 80s to around 90, which could be the hottest day of the summer thus far. At this point values are not at hot enough levels for mentions of heat advisories.

Thursday through Monday...

The upper pattern through this period will transition from southwest flow across Indiana on Thursday and Friday to more of a broad cyclonic west-northwest flow for Saturday through Monday. This is due to the expected breakdown of upper ridging over the eastern US and the gradual arrival of a broad upper low pushing across Canada.

On Thursday, the warm and humid air mass will remain across Indiana. This will keep some diurnal showers and storms across our area. Better chances for rain will arrive on Thursday Night into Friday as a cold front passing will provide additional forcing. Forecast soundings show drier air and subsidence arriving across the area on Friday afternoon in the wake of the cold front. Thus highest pops will be Thursday Night into Friday morning. At the moment, dry weather looks to arrive fro Friday afternoon.

The dry weather looks to continue through much of the weekend as the upper flow becomes more west-northwest, allowing a cooler and less humid air mass to arrive. Small chances for rain are currently in play on Sunday as a secondary, weak, and quick moving cold front passes. However, confidence is low with this feature as available moisture remains in question.

For the moment, Monday looks dry and cooler as Canadian high pressure arrives from the northwest.

AVIATION (06Z TAF Issuance)

Issued at 147 AM EDT Tue Jun 9 2026

Impacts:

- MVFR cigs after 13Z - Occasional -SHRA and isolated TSRA, mainly between 08Z and 13Z - -SHRA/TSRA possible again this evening near BMG

Discussion:

Isolated showers and thunderstorms are possible this morning as low pressure passes to the north of Indiana. Coverage and timing will be tricky to narrow down, as shower/storm activity is widely scattered and should remain so through the morning hours. The most probable time frame is between 08z and 13z. After that, there may be a bit of a break in activity but a stray shower/storm cannot be ruled out at any point today. Shower/storm chances increase again this evening, especially near BMG.

Ceilings have remained in VFR territory for the most part outside shower activity. Guidance remains pessimistic, but upstream observations show mainly VFR conditions through Illinois. Will delay the onset of MVFR conditions in the TAFs until after 13z or so, given observational trends. MVFR conditions are still expected as shower activity increases this morning.

Winds should remain out of the south/southwest, peaking during the afternoon hours and diminishing after 00z this evening.

IND WATCHES/WARNINGS/ADVISORIES

None.