textproduct: Indianapolis

KEY MESSAGES

- Dry and unseasonably high temperatures to continue through Friday, afternoon highs in the 70s

- Patchy dense fog possible south of the I-70 corridor tonight into the morning. Uncertainty is high on fog coverage.

- A wetter pattern may take shape for the Halloween weekend and/or the following week

DISCUSSION (This evening through Monday)

Issued at 151 PM EDT Mon Oct 26 2026

The broader synoptic pattern will remain fairly stagnant over the next several days, but weak progression of the longwave pattern, along with downstream impacts of low passages over the Northern/Canadian Plains will still create slight fluctuations to surface conditions throughout the week.

The main impact over the next 48 hours is likely going to be fog development late tonight into tomorrow morning. Deep ridging aloft is becoming cutoff from the upper level flow, leading to a broad area of high pressure aloft. This has lead to modest subsidence and building pressure near the surface of which is sinking southward ahead of a weak frontal passage ahead of upstream lows. This will eventually shift winds to the east, but in the meantime winds will start to calm around dusk. Areas along and south of I-70 will have the most prolonged period of calm winds leading to a greater likelihood of fog development. Given scattered upper level clouds and very dry surface conditions, there is some uncertainty in the coverage of fog, but at a minimum river valleys and well irrigated fields will likely see 1/2mi or less visibilities.

The other forecast impact for this week will be increasing winds Wednesday through Friday. By Wednesday, the mid to upper trough will near from the west leading to more unified SW flow, an increase in the pressure gradient and greater diurnal mixing. All of these combined will likely lead to gusty conditions each afternoon with sustained winds around 8-12kt with gusts around 20kt. This greater SW flow will also provide a slight warming trend with afternoon highs approaching 80 later this week.

Any lingering upper ridging will exit as multiple upper troughs move through next weekend. Uncertainty remains high on the details, but for now it appears that the best forcing and moisture will arrive overnight Saturday night into Sunday morning, with only low chances for rain during Halloween evening events.

If the front remains north, highs will be in the 70s. However, a more southern front as well as any rain would keep readings lower, especially on Sunday.

AVIATION (18Z TAF Issuance)

Issued at 132 PM EDT Mon Oct 26 2026

Impacts:

- IFR/worse visibility possible after 09Z at KHUF and KBMG

Discussion:

High pressure will slowly sink southward through the TAF period, shifting winds from SSW, to calm and then E/ESE. Winds will remain light throughout the period at less than 6kt.

The main impacts to this TAF period will be fog development late tonight into tomorrow morning near and around KHUF and KBMG. There is still some uncertainty as to the coverage of fog, and thus TEMPO groups have been added for now to showcase the uncertainty. Any fog should dissipate after 13Z.

IND WATCHES/WARNINGS/ADVISORIES

None.