textproduct: Indianapolis

KEY MESSAGES

- Hot and humid condition expected for much of the upcoming week with multiple days in the 90s and heat indices over 100 degrees

- Heat Advisory in effect Monday afternoon through Thursday

FORECAST UPDATE

Issued at 1016 PM EDT Sun Jun 28 2026

Only minor adjustments made to most forecast variables this evening, as things seem to be well in hand. A few weak radar echoes to our north suggest an outside possibility of a sprinkle or two, but nothing of impact or worthy of a measurable PoP.

Do think that guidance is underdoing fog potential, even with a bit of high cloud over portions of the area. Winds will be fairly light and dewpoints are incredibly high, particularly in the southern forecast area, and ample rain has fallen in recent days across portions of central Indiana as well. Will introduce a bit more of a fog mention to grids in parts of the area, particularly south. This is more robustly supported by NBM probabilistic data.

DISCUSSION (This evening through Sunday)

Issued at 231 PM EDT Sun Jun 28 2026

Skies remained partly to mostly cloudy across central Indiana this afternoon, and this will remain the case for the rest of the day. While broken cumulus will eventually scatter out late in the afternoon into early evening, high clouds will increase from dying thunderstorms to the northwest.

Will have to keep an eye out for the remnants of the upstream storms early this evening. They should weaken/dissipate as they approach the area, but it may take longer than the CAMs suggest per recent trends. Will keep the forecast area dry but continue to monitor.

Otherwise, a warm front with the hot airmass behind it will move across the area tonight. Forcing isn't great so am expecting mainly some clouds. However, can't rule out an isolated shower. Odds will remain below mentionable thresholds. With the moist atmosphere in place, some patchy fog may form again overnight. Lows will be in the lower to middle 70s.

On Monday morning, the warm front will be near or just east of the forecast area. A rogue shower will still be possible east, but again odds are too low to mention. The front will then exit to the east as the upper ridge builds across the area. The ridge should be strong enough to keep any storms riding around it east of the area Monday afternoon.

This ridge will persist across the area at least through Wednesday. The airmass will be a hot and humid one, with highs in the lower to perhaps middle 90s and dewpoints in the lower to middle 70s. This will produce afternoon heat indices of 100 to 105 for most areas with locally higher values. Given this, the Heat Advisory looks good and will make no changes at this time.

The ridge will may start to break down as early as Thursday, and by next weekend some guidance is showing an upper trough moving in. These will result in a return of chances of showers and thunderstorms.

Blended guidance is keeping highs in the 90s into next weekend, but that may be too warm given more clouds and increasing chances for rain with the upper trough.

AVIATION (00Z TAF Issuance)

Issued at 713 PM EDT Sun Jun 28 2026

Impacts:

- Patchy MVFR fog possible overnight, periods IFR possible BMG

- Winds less than 10KT overnight, becoming from 200 degrees at 7- 11KT Monday

Discussion:

Clearing trend continues across the area, and all sites are now VFR, though some convective debris cloudiness will impact the sites this evening into the overnight. This complicates the visibility forecast, as plentiful low level moisture remains in a background setting of relatively light winds.

Believe LAMP guidance is underforecasting fog potential, and NBM probabilities tend to hint at somewhat more possibility for visibility restrictions near daybreak (09-13Z). Will keep fog out of IND w/ winds a bit stronger and urban heat island effects, but outlying sites will carry at least TEMPO MVFR. At BMG, which is both climatologically vulnerable and in one of the wetter regions of the area in recent days, will go prevailing MVFR with tempo IFR.

Otherwise, VFR conditions will prevail once any fog dissipates in typical diurnal fashion. Winds, which may be calm to light and variable at times overnight, will become south/southwesterly during the day on Monday at 7-11KT. A spotty gust slightly higher is not impossible but should be minimal enough to forgo mention as high pressure builds in.

IND WATCHES/WARNINGS/ADVISORIES

Heat Advisory from noon Monday to 8 PM EDT Thursday for INZ021- 028>031-035>049-051>057-060>065-067>072.