textproduct: Indianapolis

KEY MESSAGES

- Showers with some thunderstorms overnight

- Rain chances will persist through the weekend. Flash flooding concerns can't be ruled out Saturday afternoon to evening

- Additional rain chances possible at times next week

FORECAST UPDATE

Issued at 1014 PM EDT Fri Jul 31 2026

The area of light rain from the initial round of lift has weakened and mostly moved off to the east of central Indiana. A few lingering scattered showers remain across the area this evening.

However, regional radar shows convection back across western Illinois into Missouri, moving east. This is associated with the upper and surface lows farther west. Forcing from the system will move east and bring the convection into central Indiana later tonight.

The stronger convection across Missouri will push southeast into better instability and not impact the area. Overall instability will increase a bit as the system gets closer, but it will remain limited. Thus, severe storms are not expected overnight. Brief heavy rain will remain a threat though.

Given the above, have lowered PoPs as needed the next couple of hours, then allowed them to return to at least likely category as the next round of forcing moves in. Removed thunder mention until later in the night.

Lowered hourly temperature forecasts based on latest trends in observations, but forecast low temperatures look good.

DISCUSSION (This evening through Friday)

Issued at 351 PM EDT Fri Jul 31 2026

Rain showers are on the doorstep of central Indiana as a low pressure system makes its way into the region. The low is expected to slowly track eastward through the weekend, providing shower and some embedded thunderstorms from this afternoon and throughout the weekend.

While CAMs are not greatly reflective of the ongoing precipitation, at least in terms of timing and location, it does continue to show that this initial round of rain is likely to diminish as it moves into the forecast area. As the atmosphere continues to moisten from the southerly flow, additional rounds of rain will continue to form over the area late this evening to overnight and continuing into the day Sunday. Saturday afternoon looks to have the best chance of flash flooding concerns with PWATs near 2" and isolated convection dumping heavy rain at times so take precautions if out driving. For total weekend rain totals, widespread amounts of 1-2, maybe up to 3 inches is expected but locally higher amounts are also probable. Where the locally higher amounts end up is the question and will depend on the speed at which the low progresses, the exact track it takes, and any mesoscale forcing that is struggling to be resolved in models. Highest totals will typically be found in the comma head of the low, which at this time looks to most likely be in the NW portion of the forecast area and areas north of there.

In addition to flooding, there is an isolated chance of severe weather for Saturday afternoon and potentially into the evening hours. Damaging winds is the main threat but can't completely rule out some rotation happening, either in the form of cold air funnels or maybe an isolated tornado due to the slow moving surface low overhead.

Going into the new week, more uncertainty arises as the global models disagree on how far to the east the low and the upper troughing system will reach thanks largely to a Bermuda high in place over the Atlantic. There are times when the low could regress back towards central Indiana bringing additional chances for rain next week. Eventually it is expected to get absorbed into the larger troughing pattern to the north and push through New England. Given these unknowns, low confidence in PoPs for next week as well as temperatures. Keeping with guidance which has at least slight to chance PoPs each day, particularly during the afternoon hours and highs generally in the 80s.

AVIATION (00Z TAF Issuance)

Issued at 706 PM EDT Fri Jul 31 2026

Impacts:

- Widespread MVFR developing toward 12Z with variable ceilings likely by Saturday afternoon

- Periods of SHRA at times through the period, with scattered TSRA mainly Saturday afternoon

Discussion:

Initial area of light rain will exit early in the period with scattered showers lingering into the early overnight. More numerous showers with perhaps a few thunderstorms will move in after 07Z or so and continue past 12Z. Another relative lull is expected mid to late morning Saturday before numerous showers and scattered storms redevelop.

Widespread MVFR ceilings will develop toward 12Z and persist Saturday morning. IFR cannot be ruled out. Saturday afternoon will see ceilings vary from low MVFR to low VFR before worsening again late afternoon into evening.

IND WATCHES/WARNINGS/ADVISORIES

None.