textproduct: Indianapolis

KEY MESSAGES

- Rain and storm chances return tonight through the weekend

- Heavy rainfall and flash flooding a primary concern late Thursday night through Friday with 1-3 inches of rain possible

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

FORECAST UPDATE

Issued at 955 AM EDT Wed Jun 24 2026

Expect a quiet day today with surface high pressure still centered across central Indiana. Latest surface analysis depicts the surface high centered near or just ESE of the area. The surface high will continue to shift east through the day allowing for winds to become southwesterly. This along with plentiful sunshine should warm temperatures into the upper 70s to low 80s.

Current visible satellite imagery depicts enhanced cloud cover across Northern IL extending northeastward into the Upper Great Lakes Region. These clouds are associated with a weak disturbance which will move in tonight. No precipitation is expected through the day, but look for a noticeable increase in clouds from the northwest around the late afternoon or evening hours. Otherwise, enjoy another comfortable summer day with dewpoints remaining in the 50s before storms chances and higher humidity return to the forecast.

DISCUSSION (Today through Tuesday)

Issued at 305 AM EDT Wed Jun 24 2026

Cool but comfortable early morning as high pressure remains across the Ohio Valley. With mostly clear skies and light winds... temperatures at 06Z were largely in the 50s under ideal radiational cooling conditions.

The high pressure will keep dry and pleasant conditions across central Indiana today but the arrival and passage of an upper level wave tonight will bring the return of scattered convection to the region. Quasi-zonal flow aloft in tandem with a frontal boundary becomes nearly stationary over the Ohio Valley will reestablish an active regime for the Ohio Valley late Thursday into the weekend....highlighted by the potential for a soaking rainfall and renewed flooding concerns late Thursday night through Friday. 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. This will bring an extended period of hot and humid weather to the region beginning Sunday and continuing for much of next week.

Today through Thursday

High pressure over the region this morning will drift east and weaken through the course of the day as an upper level wave and frontal boundary approach from the upper Midwest. Expect another pleasant day under the influence of the weakening high with low level thermals suggestive of afternoon temperatures running a few degrees warmer than highs on Tuesday. Sunshine will be abundant for most of the day but an influx of moisture aloft on the back side of the high will trend towards increased cloud coverage by late day aided by convection moving through the Great Lakes and the potential for scattered storms over Illinois along the axis of deeper moisture.

The convection to our north should weaken over lower Michigan as it moves into a more hostile environment by late afternoon with renewed development focused in the vicinity of the boundary over northern Illinois and southern Wisconsin. This will track southeast into northern Indiana through the evening and will move into northern portions of the forecast area tonight in a rapidly weakening state as model soundings show the remnants of a mid level cap and less than optimal moisture return. Anticipate however that scattered convection will linger with the presence of some elevated instability and a slow but steady pooling of higher PWATs into the region ahead of the frontal boundary into Thursday morning. Storms will carry a threat for locally heavy rainfall as the front settles over the forecast area.

Weak surface ridging attempts to reestablish over the area on Thursday but the presence of the boundary across central Indiana interacting with a progressively moist and unstable airmass by the afternoon warrants a continued threat for scattered convection focused especially across the southern two-thirds of the forecast area. Could see a few stronger cells with gusty winds but the overall risk for severe weather remains low through Thursday evening. Locally heavy rainfall will remain the primary concern.

Thursday Night through Saturday Night

A surface wave developing on the frontal boundary across the High Plains will kick east late Thursday and track east into the Ohio Valley on Friday. A feed of rich Gulf moisture will advect north into the region in advance of the surface low and interact with increasing low level convergence along the boundary to bring the potential for a widespread soaking rainfall from the predawn hours Friday through much of the day. Support continues to strengthen for highly efficient rainfall rates late Thursday night into Friday 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 on Friday with 1 to 3 inches possible.

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

The threat for scattered convection will linger into the first half of Sunday but the overall trend will be toward drier conditions as the front shifts north and deep ridging aloft expands into the Ohio Valley. 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.

Beyond the 7 day period...the upper ridge will retrograde into the central Plains as we approach the July 4 holiday weekend which would take an edge of the heat and may introduce a risk for convective clusters riding along the periphery of the ridge.

AVIATION (18Z TAF Issuance)

Issued at 138 PM EDT Wed Jun 24 2026

Impacts:

- Scattered showers and possibly a thunderstorm may impact terminals tonight

- Greater chance for showers and storms Thursday afternoon

Discussion:

VFR conditions will continue through this evening. High pressure remains the primary influence across the Ohio Valley with mainly clear skies and light winds. Mid and high clouds will steadily increase as an upper level wave approaches from the northwest. Widely scattered convection may impact KLAF during the evening while isolated to widely scattered convection could impact any given terminal during the predawn hours Thursday. PROB30s for -SHRA remain overnight, but confidence has decreased some due to dry air in the low levels. Convection may struggle to reach the terminals, especially BMG/IND.

A better chance for showers and storms will come Thursday with an approaching front. A few strong storms could impact the terminals with brief MVFR conditions.

IND WATCHES/WARNINGS/ADVISORIES

None.