textproduct: Indianapolis

KEY MESSAGES

- Dry weather through Friday with warmer than normal temperatures continuing

- Active weather this weekend with showers and storms late Saturday into Sunday

- Turning cooler Sunday and Monday

SHORT TERM (Today and tonight)

Issued at 225 AM EDT Wed Oct 15 2025

Mostly quiet weather conditions are expected through the period with surface high pressure continuing to build in. Current IR satellite imagery depicts extensive low-mid level clouds to the northwest of central Indiana. These clouds are associated with an upper trough that will push through the region during the period. Look for clouds to increase through the morning before mixing out some late in the day. This will limit diurnal heating, but highs in the 70s are still expected for most locations. Some southwestern counties could approach 80F due to less cloud cover.

There is a non-zero chance for sprinkles today with the approaching upper wave. Residual low-level dry air evident in forecast soundings will make it difficult, but cannot rule out sprinkles if sufficient top-down saturation occurs. Some low-mid level clouds are expected to linger over western portions of central Indiana tonight. This would limit diurnal cooling slightly and keep temperatures warmer compared to areas further east. Temperatures are currently expected to range from the mid-upper 40s across the east to low 50s across western counties.

LONG TERM (Thursday through Tuesday)

Issued at 225 AM EDT Wed Oct 15 2025

Thursday Through Friday.

A broad ridge of high pressure will remain in place over much of the Central US Thursday with strong upper level lows to the west and to the east. Showers and thunderstorms are expected over the upper Midwest as Gulf air advects over a nearly stationary front, but this will keep to the northwest of the forecast area. The nose of the upper level ridge will be overhead during the daytime hours on Friday with southerly surface flow gradually increasing ahead of the arriving low pressure system this weekend.

Saturday Through Tuesday.

The main focus for the long term period will be tracking the potential for both heavy rain and a few storms late Saturday into Sunday as the aforementioned low pressure system tracks into Canada and a secondary low ejects from the Four Corners region and undergoes cyclogenesis as it tracks through Oklahoma into the Tennessee Valley. The interaction between these two systems will be the catalyst for the active weather trough the weekend. The LLJ will ramp up ahead of the arrival of lift associated with the low pressure systems on Saturday with a direct connection to Gulf air bringing copious amounts of moisture to the area. Much of the timing uncertainty has been resolved with models honing in on Saturday night into early Sunday as being when the front will pass and when the heaviest rain is likely.

Both isolated flooding and a few stronger storms will be possible Saturday night into Sunday for Indiana with highest chances across the southern and southwestern portions of the state. With the timing looking more likely to be during the overnight hours vs afternoon and evening, the instability will generally remain elevated which lowers the concern for severe weather but increases the threat for heavy rain as the forcing will be moving over when the LLJ is maximized. There is still 15-25kts of shear in the lowest 1km, but without better surface based instability, the severe risk should remain southwest of the forecast area.

In addition to the very limited severe threat, isolated flooding will be a concern across the lower Ohio Valley with an axis of 2-4 inches likely somewhere in the area. There is increasing confidence in this axis being either along or south of the Ohio River, but amounts of around an inch look likely for much of south central Indiana with lesser amounts to the north.

Cooler weather is expected in the aftermath of the system late Sunday into Monday. Another low pressure system looks to quickly move through aloft Tuesday into Wednesday but models are struggling on the broader synoptic pattern which keeps confidence low in the weather through the remainder of the week.

AVIATION (12Z TAF Issuance)

Issued at 630 AM EDT Wed Oct 15 2025

Impacts:

- Patchy ground fog possible at outlying TAF sites through 12Z.

Discussion:

VFR conditions are expected through the TAF period. Patchy ground fog is possible at the outlying TAF sites through 12Z. Clouds are moving into central Indiana with ceilings between 4000-10000ft. MVFR ceilings are unlikely today, but cannot rule it out briefly near LAF along with a stray sprinkle at any site.

Winds may remain light and variable through the morning though a dominant northeasterly component is expected. Winds pick up a bit during the afternoon, but should remain under 10kt and maintain a northeasterly direction.

IND WATCHES/WARNINGS/ADVISORIES

None.