textproduct: Indianapolis

KEY MESSAGES

- One more warm day today

- Widespread rain expected tonight into Friday morning, with amounts of one half to one inch

- Dry and much cooler weather expected over the weekend into next week; potential for first lows to drop into the 30s across portions of central Indiana Tuesday morning

DISCUSSION (Today through Wednesday)

Issued at 327 AM EDT Thu Oct 1 2026

Main focus remains on the cold front expected to slowly sag through the area late today into Friday, which will serve as focus for widespread rainfall, particularly this evening into Friday morning.

Limited instability will be present in a fairly pseudotropical airmass owing largely to the tropical moisture brought into the system by the remnants of Hurricane Polo in recent days, which will instead present deeply saturated, near moist adiabatic profiles, promoting locally heavy downpours as the primary concern.

Precipitable water values may approach 2 inches at their peak, which is near climatological maximum for the time of year, but without a more substantial convective component or stronger forcing, expect QPF amounts to be limited to a widespread one half to one inch through the event, which is well within the capacity of the current hydrologic situation per river ensembles and flash flood guidance.

HREF Local Probability Matched Means do indicate an outside chance for isolated areas to approach two inches, but this would be over a 24 hour period, which again would be of limited impact.

Two strong areas of cool Canadian high pressure are expected to traverse the Great Lakes in the wake of the cold front this weekend into next week, bringing the coolest air of the Autumn season thus far to central Indiana, along with another prolonged dry spell.

Highs today will again rise well into the 80s across most areas, with lows tonight in the upper 50s to mid 60s, largely modulated by low level humidity, with much cooler conditions thereafter once the front has fully exited the area. Highs from Friday onward will largely fall in the mid 60s to mid 70s, with lows generally in the 40s to around 50, though early next week the first lows in the 30s will be possible Monday night, mainly northeast.

AVIATION (06Z TAF Issuance)

Issued at 1234 AM EDT Thu Oct 1 2026

Impacts:

- Non-convective LLWS overnight

- Southwesterly wind gusts between 20-25 KT Thursday midday - afternoon

- Showers and storms possible late in the period

Discussion:

Mostly mid and high cloud is expected overnight, though strengthening flow fields ahead of an approaching frontal system will likely produce some LLWS based around 1500 feet with winds around 220 from 35-40KT at the top of the nocturnal inversion.

As mixing ramps up during the morning hours Thursday, expect wind gusts to begin as early as 15Z, with sustained winds from around 220- 230 at 10-15KT gusting 20-25KT. These gusts will subside with frontal passage in the late afternoon/evening, but then a threat for showers and perhaps thunderstorms will overspread the area. Will carry a VCSH mention and a PROB30 for thunder at all sites Thursday evening.

Expecting predominantly VFR conditions outside of any convection.

IND WATCHES/WARNINGS/ADVISORIES

None.