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

FORECAST UPDATE

Issued at 957 AM EDT Thu Oct 1 2026

Minimal changes were needed to the forecast but did tweak winds some for today. Highs today will be well above normal and expected to reach the mid 80s to near 90 with rain moving in from the NW late in the day. This warmth will be short lived as the cold front bringing rain tonight and into tomorrow will also bring much cooler weather for tomorrow and the following days.

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 (12Z TAF Issuance)

Issued at 636 AM EDT Thu Oct 1 2026

Impacts:

- Non-convective LLWS early in the period

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

- Rain expected tonight, storms possible

- IFR conditions possible very late in the period

Discussion:

Modest LLWS will continue for the first few hours of the period until wind gusts ramp up around midday as mixing increases. Increasing mid and high clouds can be expected today as moisture increases ahead of an approaching low pressure system.

Sustained winds of 10-15KT with gusts 20-25KT can be expected from midday into the afternoon, from around 220-230 degrees. Gusts will subside in the evening and winds will begin to veer westerly and then northerly as the front slowly sags into the area. Widespread rain will accompany this front, and a few rumbles of thunder cannot be ruled out, but now think the PROB30 groups are a bit too aggressive given the minimal instability.

Conditions will likely deteriorate as the front passes, with low clouds likely to develop. Guidance suggests widespread IFR late tonight into Friday.

IND WATCHES/WARNINGS/ADVISORIES

None.