textproduct: Indianapolis

KEY MESSAGES

- Clouds will dissipate through the afternoon hours with mostly clear skies by the evening

- Near record temperatures Monday and Tuesday

- Showers return mid-week

- Coolest air of the season so far next weekend

FORECAST UPDATE

Issued at 935 AM EDT Sun Oct 11 2026

Dreary morning as the region remains within the backwash of the Isaias remnants. Thick low stratus along with patchy drizzle and a few light showers persisted across the forecast area although the back edge of the clearing was just west of the Illinois state line. 13Z temperatures were in the upper 50s and lower 60s.

The ongoing drizzle will diminish over the next couple hours as drier air aloft slowly filters down into the boundary layer. The back edge of the stratus deck will progress east steadily into the afternoon as the trailing upper low with Isaias moves into the central Appalachians. Expect most if not all of the forecast area will have sunshine by late afternoon.

Temperatures will be heavily dependent on how long it stays cloudy...with highs ranging from around 70 in the far east to near 80 in the Wabash Valley. Zone and grid updates out.

DISCUSSION (Today through Saturday)

Issued at 131 AM EDT Sun Oct 11 2026

Today Through Monday.

The synoptic setup features a weakening mid-level trough associated with the remnants of Isaias exiting to the east with lingering mid- level moist advection and weak surface frontogenesis across southeastern central Indiana. HREF component members including the HRRR and NAM3km show remnant light rain and low-level cloudiness ending west to east between 12Z and 16Z as subsidence behind the trough axis takes hold. Deepening boundary layer mixing under weak northwest surface flow behind the departing surface boundary will clear cloud cover by mid-afternoon. Thermal profiles off the GFS and ECMWF show 850 MB temperatures near 10C to 12C, supporting daytime highs in the low to mid 70s across the CWA. Surface high pressure centered over the Ohio Valley will maintain light and variable winds overnight, allowing radiational cooling to drop surface temperatures into the mid 50s. Fog looks likely across eastern Indiana tonight as the clearing reaches the area and winds drop to near calm. The western extent of the fog remains uncertain and will depend on the timing of the clearing.

In the aftermath of the exiting low, a surface high will slide east toward the Mid-Atlantic coast on Monday as a broad trough amplifies across the Northern Plains. Surface pressure falls across the Upper Midwest will tighten the regional pressure gradient, strengthening low-level southerly to southwesterly return flow. Deterministic GFS and ECMWF soundings display a deep boundary layer with winds at the top around 20-25kt. Model guidance shows dry mid-level air beneath deep subsidence, which will allow for RH values to drop to around 40 to 50 percent. With this strong WAA and clouds limited to high cirrus, much above normal temperatures are expected with some spots near the Illinois border reaching close to 90 degrees. Gusty southwesterly winds of 15 to 25 mph are expected during the afternoon hours before relaxing slightly Monday night as the boundary layer decouples under mostly clear skies.

Tuesday Through Saturday.

The unseasonably warm thermal ridge will remain positioned across the Ohio Valley on Tuesday ahead of a potent cold front extending from an upper-level low moving across Ontario and the Upper Great Lakes. Models continue to show good agreement in high temperatures climbing into the upper 80s under mostly sunny skies with another day of deep boundary layer mixing. Moisture transport will begin to ramp up late Tuesday night along the pre-frontal trough axis as a 40 kt LLJ advects Gulf moisture, increasing PWATs above 1.3 inches. Scattered shower activity will enter northwestern counties after 06Z Wednesday.

Model guidance, including deterministic runs and ensemble clusters from the GEFS and EPS, shows the surface cold front decelerating and stalling west-to-east across central Indiana Wednesday and Thursday as it becomes parallel to the mid-level atmospheric flow. Strong lower-level baroclinic forcing combined with broad synoptic lift from an approaching shortwave trough will generate widespread precipitation along and south of the boundary. Soundings show modest MUCAPE between 300-800 J/kg along with 0-6 km bulk shear exceeding 40 kt, supporting embedded elevated convection and isolated heavier rainfall totals. While models have a good idea on the broader synoptic pattern, there remains quite a bit of uncertainty as to the phasing of the system and where the stronger forcing sets up which keeps confidence low on precipitation totals.

The upper trough axis clears the region early Friday, driving the frontal boundary well south into the Tennessee Valley and opening the door for strong post-frontal CAA. Surface high pressure of Canadian origin will build southeastward from the Northern Plains into the Great Lakes and Ohio Valley. Gusty northwesterly winds Friday morning will gradually diminish by Saturday as the core of the high centers over the region. High temperatures on Friday will reach the upper 60s, cooling further on Saturday to the upper 50s. Clear skies and light winds Friday night and Saturday night will promote efficient radiational cooling, dropping overnight lows into the upper 30s to lower 40s across central Indiana with frost looking increasingly likely along with a potential freeze in more rural and typically cooler areas.

AVIATION (12Z TAF Issuance)

Issued at 609 AM EDT Sun Oct 11 2026

Impacts:

-Isolated rain may continue through 14Z, coverage minimal -MVFR cigs to continue through the early afternoon hours with periods of IFR through 14Z

Discussion:

Rain has generally come to an end outside of isolated showers towards HUF. There have been some pockets of lowered vsbys due to mist, but by 12Z vsbys should be P6SM. IFR cigs will continue at BMG and IND through mid-morning with MVFR persisting through the early afternoon. Clouds will clear from west to east through the daytime hours with VFR conditions and mostly clear skies by 21Z. There may be some fog/low stratus tonight after 06Z, but expect that to remain east of IND and BMG. Winds will continue to become more northerly through the morning at around 5-10kt before becoming near calm by 00Z.

IND WATCHES/WARNINGS/ADVISORIES

None.