textproduct: Indianapolis

KEY MESSAGES

- Peak heat indices around 100 degrees each afternoon through Saturday

- Greater chance for showers and storms today through the first half of the weekend, primarily during the afternoon and evening

- Isolated strong to severe thunderstorms are possible Saturday PM, Damaging wind gusts are the primary threat

FORECAST UPDATE

Issued at 1000 PM EDT Thu Jul 16 2026

Typical humid mid-summer pattern will continue overnight, with lingering isolated showers over northern Marion County and near Carroll County expected to fade by 03Z. Localized impacts within northern Indianapolis Metro may include ponding of low-lying areas and brief minor flooding. Otherwise oppressive conditions featuring light winds and dewpoints in at least the mid-70s for most locations, will set the stage for areas of fog after midnight, especially over western and southern counties...which could have quick drops in visibility over short distances, especially near low- lying areas. Lows by early Friday will be 72-75 degrees for most locales.

DISCUSSION (This evening through Thursday)

Issued at 300 PM EDT Thu Jul 16 2026

This afternoon through tonight...

Upper ridging and weak surface high pressure will continue to promote mostly quiet weather for much of the area. The stagnant suppressed airmass has kept hot-humid conditions in place with a Heat Advisory still in effect for north/northeast portions of central Indiana, including the Indianapolis metro, through 8PM EDT today.

Isolated to scattered diurnal convection has developed across far southwestern counties where deeper moisture is located. Latest observations depict dewpoints well in the 70s in those areas. Slightly lower dewpoints further northeast along with weaker forcing has limited convective development, but isolated showers or a stray thunderstorm cannot be ruled out. Convection will likely dissipate shortly after sunset. Patchy Canadian wildfire smoke may slowly move into far north/northeast portions of the area as light winds turn more northerly into the evening.

Friday through Saturday night...

A more active pattern is expected with multiple disturbances moving through the region. The first disturbance will move in on Friday supporting higher rain chances. Modest ascent from the mid-upper level feature combined with daytime heating of a hot-humid airmass will promote numerous showers and thunderstorms. Severe weather is not expected, but efficient rainfall rates from warm rain processes could result in localized flooding, especially if any training occurs. Additional scattered convection can be expected late Saturday as another shortwave and associated cold front push through.

Moderate to strong destabilization ahead of the approaching cold front late Saturday along with modest enhancement of mid-upper level flow could promote isolated severe thunderstorms, primarily across northern portions of central Indiana. Forecast soundings depict around 20-30 kt of effective shear, strong destabilization with steep low-level lapse rates, and DCAPE values as high as 1000 to 1400 J/KG which support the threat. The primary convective hazard is damaging wind gusts. Isolated large hail cannot be ruled out either, but the threat will quickly lessen as upscale growth occurs. The main timing appears to be from the mid afternoon through the early overnight hours.

Sunday into next week...

Long range guidance generally depicts upper ridging and weak surface high pressure building in Sunday behind the departing cold front. This will provide quiet weather with cooler-drier conditions. Guidance then suggest another shortwave approaches late Monday into Tuesday morning. Exact details remain uncertain with this disturbance due to diverging model solutions. It is worth noting guidance suggest more significant cold air advection with this disturbance which favors even cooler and drier conditions towards the middle of next week.

AVIATION (06Z TAF Issuance)

Issued at 1259 AM EDT Fri Jul 17 2026

Impacts:

- MVFR/worse VIS possible in BR through 12Z outside of KIND - Scattered/numerous -SHRA/TSRA Friday afternoon/early evening

Discussion:

Mainly VFR conditions are expected near central Indiana terminals through the TAF period...with possibly several hours of MVFR/worse visibility tonight from BR...and possibly several more, likely shorter periods of generally MVFR within 18Z-23Z Friday amid stronger SHRA/TSRA. Overall lower confidence in both potential periods...tonight due to scattered clouds so far across the region...and later Friday per the weak steering and disorganized forcing of what should ultimately be several hours of scattered/numerous convection.

Winds will be calm or light/variable into Friday morning...and then from generally 190-250 degrees sustained at 3-6KT after 16Z outside of stronger cells...with flow closer to 6-9KT at KIND through 12Z Saturday.

IND WATCHES/WARNINGS/ADVISORIES

None.