textproduct: Indianapolis

KEY MESSAGES

- Strong to severe storms possible, mainly this evening into tonight, with damaging winds and heavy rain/localized flooding the primary threats

- Additional rain possible at times Friday through the weekend with localized flooding possible

- Warmer and drier again next week, though with more modest humidity than experienced the first week of the month

DISCUSSION (Today through Wednesday)

Issued at 257 AM EDT Thu Jul 9 2026

TODAY AND TONIGHT -

Aside from some patchy fog in the outlying and favored areas in the light winds and high humidity airmass, expect generally quiet weather this morning, with thunderstorm chances ramping up through the day as the airmass destabilizes and a convectively enhanced upper level disturbance approaches the area.

CAMs in general are depicting the evolution of one or more clusters of storms into a linear structure late in the day into the overnight hours tonight, with primarily a concern for a few damaging wind gusts. Deep layer shear is modest but sufficient, and may be enhanced slightly beyond what guidance depicts by the aforementioned MCV. Diurnal timing is not ideal though moderately strong instability should remain in place into the overnight hours - approaching and possibly exceeding MUCAPE values of 2000 J/kg. Seasonably high wet-bulb zero values will limit hail threat to primarily small hail in the stronger cores absent any more discrete convection, which appears unlikely, and while a brief QLCS spin-up cannot be ruled out, damaging winds in a seasonable setting of a cold-pool driven MCS will be the primary concern.

Despite precipitable water values approaching 2 inches, well in excess of the climatological 90th percentile, the (mostly) progressive CAM solutions do give some optimism that despite undeniable heavy rain potential, hydrologic threat should be relatively limited with today and tonight's convection, though mesoscale reorientation of the low level environment in the form of boundaries and the larger scale low to mid level flow will always be a concern in such setups, and the slight risk for excessive rainfall day one is certainly reasonable.

Overall, current expectation is for a broken line of storms to possibly move into central Indiana during the evening hours, perhaps just prior to nightfall, and push through the area to the east/southeast - with southwestern portions of the area the most likely area for both severe and hydrologic concerns.

FRIDAY INTO SUNDAY -

Another upper level wave will move slowly through the region Friday into Saturday, though models differ in their handling and intensity of the disturbance. A continued moist airmass will promote at least moderate destabilization, and one or more clusters of storms will be possible Friday into Friday night and perhaps on Saturday as well, though the threat will lessen and shift southward with time, and be focused primarily along remnant boundaries from previous convection, lessening the predictability as time goes on.

An isolated strong to severe threat cannot be entirely ruled out, though hydro concerns will likely be slightly more pressing as the area has been decently wet in recent weeks, and the aforementioned plentiful moisture combined with what may be fairly slow storm motions outside of more organized clusters could present a localized flash flood threat - WPC excessive rainfall outlooks outline this well.

NEXT WEEK -

The predominant story next week will be a reassertion of summertime heat as a brief pseudo-Rex block pattern forms with the western CONUS ridge sliding back eastward atop weak upper level low pressure to our south, gradually reconnecting with the Bermuda high over the southeast. Temperatures will climb back towards the 90 degree mark in spots, though with slightly more reasonable dewpoints than the first week of the month, keeping max apparent temperatures still toasty but far more manageable in the low to mid 90s.

The high pressure aloft and at the surface will keep the area dry for the most part, though airmass thunderstorms cannot be entirely ruled out near peak heating many days. That said, these are quite low predictability days ahead of time and will not merit mentionable PoPs on most days.

AVIATION (12Z TAF Issuance)

Issued at 624 AM EDT Thu Jul 9 2026

Impacts:

- MVFR, TEMPO IFR fog in the first hour or so

- Showers and storms possible at all sites this evening into the overnight

Discussion:

As expected, fog has formed at the outlying sites, with visibilities fluctuating between MVFR and IFR. Conditions should be steadily improving shortly after valid time, with VFR returning around 13Z in typical diurnal fashion.

Once fog mixes out, VFR conditions will remain throughout the majority of the period, the possible exception being this evening when showers and storms are possible at the sites. Will carry VCSH for now with a PROB30 group for thunder at all sites.

Winds will be calm to light and variable early, becoming southwesterly (200-230 degrees) during the day, with a few gusts into the mid teens range possible at most sites.

IND WATCHES/WARNINGS/ADVISORIES

None.