textproduct: Indianapolis

KEY MESSAGES

- Dry weather through Saturday with some elevated haze and smoke from Canadian wildfires

- Hot and humid conditions return Sunday and Monday with highs reaching the 90s

- Storm complexes possible Sunday night and Monday nights

DISCUSSION (This evening through Friday)

Issued at 132 PM EDT Fri Jul 24 2026

Overview.

Dry and warm weather will continue through Saturday under high pressure, though skies may appear hazy due to elevated smoke in addition to the high clouds. Temperatures and humidity will increase significantly Sunday into Monday as a heat dome expands eastward. Thunderstorm complexes will bring rain and storm chances late Sunday night through Monday night, with localized severe weather possible. Dry weather then is expected through the remainder of the week with warmer than normal temperatures.

Tonight Through Sunday.

Surface high pressure centered across the eastern Great Lakes will maintain control of central Indiana weather through Saturday, promoting broad-scale subsidence and light easterly winds veering to southeasterly. High-resolution models, including HRRR and RAP smoke transport fields, reveals a persistent plume of elevated wildfire smoke advecting southeastward within upper-level northwest flow beginning late tonight. This bring a return to hazy skies throughout Saturday; however, boundary-layer mixing depth and surface concentrations remain low enough to preclude surface visibility or air quality impacts.

As the surface anticyclone shifts toward the Mid-Atlantic Saturday night into Sunday, low-level WAA will intensify. A 850 MB moisture plume will surge northward, pushing surface dewpoints into the low to mid-70s by Sunday afternoon. Model soundings show steepening mid- level lapse rates (6.5 to 7.0 C/km) beneath an amplifying upper- level ridge. High temperatures on Sunday will climb into the upper 80s to low 90s, yielding afternoon SBCAPE values exceeding 2500-3000 J/kg. High MLCIN and weak synoptic forcing should suppress diurnal thunderstorm development through much of the daytime on Sunday, keeping conditions largely cap-inhibited until late evening.

Sunday Night Through Friday.

The synoptic regime through early next week will feature a major upper-level heat dome centered over the Central Plains, placing the Ohio Valley along the eastern periphery in a classic "ring of fire" northwest flow pattern. Guidance from the GFS, ECMWF, and their ensemble suites (GEFS and EPS) indicates multiple mid-level shortwaves traversing the periphery of the ridge, interacting with the warm, unstable boundary layer to trigger organized storm complexes both Sunday night and Monday night. Monday night currently looks to have the better chance for impacts across central Indiana based on the current axis of the ridge, but that looks to generally be more focused towards northeast Indiana. That being said, there may be a southwestward trend in where the storm complexes may impact as the global models often pin the initiation point too far north and don't track the progression along the theta-e gradient as well as some of the higher resolution models.

High DCAPE values exceeding 1000 J/kg and PWAT values near 2.00 inches will make damaging wind gusts and localized heavy rainfall the primary hazards with any organized MCS. In addition to the storm threats, heat index values will climb into the 100-105 range Monday which may need heat headlines in the coming days.

Following the cold frontal passage early Tuesday, drier continental air will briefly build into the Great Lakes, pushing the primary thunderstorm boundary south toward the Ohio River. High temperatures on Tuesday and Wednesday will hover in the upper 80s with reduced dewpoints. However, global ensembles agree on sub-tropical ridge amplification over the Ohio Valley by Thursday and Friday. 500 MB heights rising above 590dm, combined with strong solar insolation and evapotranspiration, will drive maximum temperatures into the mid- 90s with heat index values approaching triple digits by the end of the period.

AVIATION (18Z TAF Issuance)

Issued at 132 PM EDT Fri Jul 24 2026

Impacts:

- None

Discussion:

VFR conditions are expected through the TAF period with no impactful weather. Diurnal cu will gradually dissipate towards sunset leaving behind widespread high cirrus. Winds will remain variable through the TAF period at 5kts or less with a predominately northerly direction through tonight before becoming southerly tomorrow.

IND WATCHES/WARNINGS/ADVISORIES

None.