textproduct: Indianapolis

KEY MESSAGES

- Flood Watch from late this afternoon through Saturday morning for southwest portions of central Indiana with 1 to 3 inches of rain possible

- Multiple rounds of showers and storms producing torrential rainfall and localized flooding later today into the weekend

- Isolated severe storms possible as well this afternoon and evening and again on Friday

- Hot and humid conditions expected for much of next week with multiple days in the 90s

DISCUSSION (Today through Wednesday)

Issued at 301 AM EDT Thu Jun 25 2026

Convection continues to weaken across the northern Wabash Valley early this morning with a more stable and drier airmass lingering across the region. With light southerly flow...temperatures ranged from the mid 60s to the lower 70s at 06Z.

The aforementioned convection is in advance of a diffuse frontal boundary currently extending from the western Great Lakes back into the Missouri Valley. Quasi-zonal flow aloft in tandem with the boundary drifting south and becoming nearly stationary over the Ohio Valley will reestablish an active regime with multiple opportunities for showers and storms today through the first half of the weekend. Storms will carry a renewed concern for flooding focused especially on Friday and Friday night. The front will be forced north of the region by late weekend as the upper level pattern transitions to deep ridging over the Mississippi and Ohio Valleys resulting in an extended period of hot and humid weather for much of next week.

Today through Saturday Night

The presence of lingering dry air through the column and a capping inversion near 600mb noted nicely on the KIND ACARS will aid in further weakening of ongoing convection and decreasing coverage over the next several hours. There remains subtle instability present below the cap which combined with an increase in westerly 850mb flow and gradual moisture advection into the region will be enough to maintain isolated to scattered convection through daybreak drifting south to near if not just south of the I-70 corridor. Expect any leftover showers to largely diminish later this morning as low level flow weakens.

The presence of the boundary slipping south into the forecast area interacting with a progressively moist and unstable airmass this afternoon will support renewed development of scattered convection focused especially across the southern two-thirds of the forecast area. A modestly unstable but low shear environment supports more disorganized pulse intensity convection for the afternoon and early evening with the potential for localized damaging winds from any collapsing cells. PWATs will continue to rise throughout the day with torrential rainfall accompanying convection and bringing the initial threat for localized flooding that will be present across the area into the weekend.

Convection will decrease in coverage this evening and remain largely confined to the vicinity of the frontal boundary likely to be located across the southern part of the forecast area. A surface wave developing on the frontal boundary across the High Plains will eject east this evening and track into the Ohio Valley on Friday. A feed of rich Gulf moisture will advect into the region in advance of the surface low and interact with increasing low level convergence along the boundary to bring the potential for more widespread heavier rainfall from the predawn hours Friday into Friday night. Expect an airmass supportive of highly efficient rainfall rates during the period focused across the southern half of the forecast area...highlighted by PWAT values climbing to near 2 inches...deep saturation through the column and a freezing level rising to near 15kft suggestive of warm rain processes.

Considering the recent wet conditions from the active pattern of late...torrential rainfall producing flash flooding is a growing concern and have introduced a Flood Watch for the southwest part of the forecast area west of a Terre Haute to Bedford line where confidence is highest in potential impacts based on antecedent conditions and where PWATs are likely to be the highest. 1 to 3 inches of rain with locally higher amounts are expected in the lower Wabash Valley through Saturday. Anticipate the Watch will need to be extended further east across the rest of the southern forecast area at some point later today or tonight but impacts from more widespread heavy rainfall in these areas are not expected until during the day Friday at the earliest.

An isolated severe weather risk remains within the scope of possibilities on Friday afternoon and evening but confidence is higher in this being a greater concern near or just south of the front which will be located somewhere across southern Indiana. The NAMNest is showing as a clear outlier with a slightly deeper surface low tracking further north across the area and consequently pulling the boundary back north as well. Should this solution come to fruition...a concern for damaging winds and a few tornadoes would be on the table with increasing low level shear and helicity across the front. The favored output at this time is with a more southern position to the boundary throughout the day Friday with deepest instability and shear largely remaining southwest of the forecast area.

The front will meander over the region through Saturday night... possibly shifting towards the Ohio River Friday night before returning north on Saturday. The continued presence of the boundary over the region will keep the risk for scattered convection across the forecast area through the first half of the weekend. Will need to monitor the possibility of a convective cluster impacting the region Saturday night on the eastern side of an approaching upper level ridge that will eventually force the frontal boundary back to the north of the region on Sunday.

Sunday into Next Week

In the wake of convection early Sunday...the upper ridge will expand into the area with the front lifting away to our north. This will serve as the transition point towards progressively hotter and more humid conditions that are likely to last well into next week. Multiple days with highs in the 90s are anticipated through much of next week with the highest heat indices of the summer so far rising into the low 100s during the afternoons. Isolated late afternoon and evening convection may develop by the second half of next week as the mid level heights begin to fall back. As the upper ridge will retrograde back to the southwest by next weekend...will need to monitor for an increased risk for convective clusters riding along the periphery of the ridge impacting parts of the region.

AVIATION (12Z TAF Issuance)

Issued at 615 AM EDT Thu Jun 25 2026

Impacts:

- Scattered showers and possibly a thunderstorm may briefly impact KBMG for an hour or two after 12Z

- Additional storms possible this afternoon and evening

- MVFR ceilings and more widespread showers arrive near daybreak Friday

Discussion:

Predominantly VFR conditions expected through the period outside of any possible impacts from convection.

Scattered convection continues to track south across central Indiana early this morning. By TAF issuance time...showers are expected to be south of I-70 and may briefly impact KBMG through 13 to 14Z. The rest of the morning should be quiet but renewed convective development is anticipated during the afternoon as a frontal boundary sags across the area. Better instability present this afternoon will warrant the inclusion of scattered thunder and will carry a 4 to 6 hour period of PROB30s at all terminals except for KLAF.

Showers will linger in the vicinity of the boundary across southern portions of central Indiana tonight in advance of an area of more widespread rainfall that will expand into the region just before daybreak Friday. MVFR ceilings are likely to accompany the broader area of rainfall early Friday.

Light S/SW winds early this morning will become W/SW up to 10kts this afternoon before becoming light and variable again this evening.

IND WATCHES/WARNINGS/ADVISORIES

Flood Watch from 5 PM EDT this afternoon through Saturday morning for INZ051>053-060>062-067>070.