textproduct: Indianapolis

KEY MESSAGES

- Widespread minor/moderate river flooding continues south of I-70

- Locally heavy rainfall is expected tonight into Wednesday, which will exacerbate or prolong ongoing flooding

- Scattered severe storms with all hazards are possible tonight and Wednesday

- Record warmth today but cooler temperatures expected Thursday into the weekend

SHORT TERM (Today through Wednesday Night)

Issued at 300 AM EDT Tue Mar 10 2026

Stratus continues to increase in coverage across the forecast area early this morning as warm advection strengthens across the Ohio Valley. Temperatures remained warm with 07Z readings in the 60s.

Active next 48 hours setting up across the region as a frontal boundary currently stretched out across the Great Lakes slowly drifts south into northern Indiana by late today. A surface low currently organizing over the High Plains will track E/NE along the boundary and serve as a focal point for convective development by late afternoon and early evening across the mid Mississippi Valley and lower Great Lakes. Convection will remain to the northwest of the forecast area initially through most of this evening...with greater impacts coming late tonight and Wednesday as the front gradually pivots across central Indiana and the Ohio Valley.

Through Early This Evening

As mentioned...stratus has become more widespread and better organized across the region since Monday evening as low level moisture advects into the Ohio Valley from the southeast. The KIND ACARS sounding shows very nicely that the moisture has become trapped beneath an inversion near 900mb that should only strengthen through daybreak. Not out of the question to see a few light showers or drizzle develop over the next few hours as a subtle wave aloft passes south of the region through the Tennessee Valley otherwise expecting predominantly dry conditions through the morning.

Stratus will remain prevalent into this afternoon with the potential for breaks to develop in the canopy as boundary layer mixing increases. The influx of warm...moist air from the Gulf will bring an unseasonably humid airmass into the region this afternoon with dewpoints in to the low and mid 60s. Model soundings show an increasingly unstable environment developing across the region with impressive mid level lapse rates. Locally across central Indiana however...that will not mean much as a stout cap sets up in the 700- 750mb layer and keeps a lid on any convective development. The approach of the aforementioned surface wave in tandem with an increase in 850mb flow will help to unlock the convective development near the boundary by late today with the potential for explosive initiation with supercells as the dominant convective mode as the cap breaks from northeast Missouri into northwest Indiana.

This Evening through Wednesday Night

There is growing confidence that the cap will hold for much of the evening across the forecast area with robust convection remaining in the vicinity of the boundary extending from near Kansas City to just south of Chicago to near Detroit. With boundary layer flow persisting from the W/SW...storms should remain largely north of the forecast area as a result. The arrival of stronger 850mb flow in the 03 to 06Z timeframe will finally aid in weakening the cap and may enable convection to develop further south as the boundary drifts in our direction.

Confidence is increasing in more substantial convective impacts across the forecast area coming in the overnight and early Wednesday morning period with the front dropping into the northern Wabash Valley by 12Z Wednesday. Storms tonight will carry a tornado and large hail risk...especially across far northern portions of the forecast area...with strong 0-1km SRH values and hodographs showing solid curvature in the lowest 2-3km and abundant instability within the hail growth zone. Convective mode will become increasingly chaotic as the night progresses with both multicell and supercells likely as clusters shift southeast into the forecast area through the predawn hours. This will likely promote damaging winds as an increasing threat with 50+kt winds in the lowest 2-3km and a more unidirectional wind profile while hail and tornadoes transition to more of a secondary risk.

Areas of convection will be ongoing Wednesday morning and present lower confidence in the severe weather threat ahead of the front by the afternoon as it presses through the forecast area. The greatest concern for convective intensity will be across the southeast half of the forecast area which where any recovery in instability would likely be enough to generate strong to isolated severe wind gusts with ample shear and SRH lingering within the boundary layer. The availability instability however remains the question mark as lingering showers and leftover convective cloud debris from earlier may not allow for much of a recovery over the southeast half of the forecast area with a more substantial threat for severe weather displaced instead to the southeast of central Indiana where airmass recovery will be more pronounced. Rain will end Wednesday evening with skies clearing late as a colder and drier airmass expands into the region.

While the severe weather threat is valid...the flooding potential remains a concern with heavy rainfall impacting much of the forecast area late tonight into Wednesday. Precipitable water values will peak near 1.50 inches which is near 300% of the climatological normal. While the convective nature of the rainfall will produce non-uniform rainfall totals...most locations will see 1 to 1.5 inches of rain with pockets of higher amounts expected. This will exacerbate and potentially worsen ongoing river flooding while offering the risk for localized flash flooding due to high rainfall rates.

Temps...with the warm start this morning...there is high potential to break a record high this afternoon as mid 70s abound across the forecast area. The record high for today at Indy is 74 from 2009 and the current forecast is for a high of 75. Temperatures will remain in the 60s south of the front tonight and Wednesday morning then will begin falling once the front passes. Much colder air Wednesday night will serve as a reminder that winter is not technically over yet. Expect lows in the low to mid 30s by early Thursday morning.

LONG TERM (Thursday through Monday)

Issued at 300 AM EDT Tue Mar 10 2026

The upper level pattern across the country will transition to northwest flow in the wake of the midweek system with a flat ridge off the California coast. Fast moving storm systems will track through the progressive flow aloft and remain north of central Indiana through the first part of the weekend. An amplifying upper level trough will help to strengthen low pressure over the central Plains Sunday. The low will pivot across the region late Sunday with a trailing cold front bringing another opportunity for rainfall to wrap up the weekend. Colder air will then spread into the Ohio Valley for early next week as the upper level pattern becomes increasingly amplified with a western ridge and a eastern trough.

Lingering rain showers across southeast parts of the area will depart Wednesday evening with clearing into early Thursday as deep subsidence overspreads the Ohio Valley with a broad area of high pressure. Briefly cooler temperatures for Thursday will bounce back to slightly above normal levels Friday and Saturday as low level flow swings back around to southerly and becomes gusty at times. With the exception of a fast moving surface wave moving through the Great Lakes early Friday and bringing a few light showers to northern portions of the forecast area...dry weather is expected through Saturday evening.

A warm front will extend into the region by late Saturday as low pressure begins to organize over the central Rockies. Precipitation should remain to the north of the boundary for much of Saturday night. The ejection of the surface low quickly into the region by late Sunday will bring rain and embedded convection as the attendant cold front sweeps across the region Sunday evening. Snow may mix in Sunday night before precipitation ends as colder air will advect in rapidly behind the boundary.

In the wake of this system...colder air will filter into the area with an amplified upper level ridge west-trough east developing for the first half of next week. After highs in the low and mid 60s over much of the region Sunday....temperatures will struggle to rise out of the 30s Monday and Tuesday with below normal readings lingering for much of next week.

AVIATION (12Z TAF Issuance)

Issued at 540 AM EDT Tue Mar 10 2026

Impacts:

- MVFR ceilings through the first half of the day - Scattered showers and possibly thunderstorms by mid to late evening at KLAF then late tonight at the other terminals with MVFR ceilings returning - Periodic wind gusts peaking at around 25kts, especially this afternoon and tonight

Discussion:

Stratus encompasses much of central Indiana early this morning and will largely persist at MVFR levels into the early to mid afternoon. Stratus will mix out and scatter somewhat late today into this evening. Convection will fire to the northwest of the region late today and spread east into northern Indiana this evening. There remains a possibility that storms may make it as far south as KLAF mid to late evening but overall confidence is growing in convective impacts at the terminals holding off until late tonight continuing into Wednesday morning.

S/SW winds will continue through tonight with peak gusts at around 25kts this afternoon into early Wednesday morning.

IND WATCHES/WARNINGS/ADVISORIES

None.