textproduct: Indianapolis

KEY MESSAGES

- Dry through Saturday with seasonable temperatures

- Hotter and more humid air arrives Sunday and persists through much of next week

- Isolated thunderstorms may return mid to late week next week

FORECAST UPDATE

Issued at 934 AM EDT Sat Aug 29 2026

The forecast remains steady-state this morning as high pressure continues through a majority of the troposphere. The major update this morning is associated with a large MCS over the upper- Mississippi Valley. Although direct impacts will be minimal, upper level cloud cover should increase substantially for portions of the late morning before becoming diffuse this afternoon. This may curtail afternoon highs by a degree or two.

DISCUSSION (Today through Friday)

Issued at 223 AM EDT Sat Aug 29 2026

Surface analysis early this morning shows strong high pressure in place across NY and PA. Light SE flow was in place across Indiana, under the influence of this high. Low pressure was found across SD, and thunderstorms were found ahead of a cold front over the high plains. Aloft, Ridging was found over the Central Plains states, while a trough was found along the Appalachians. This was resulting in NW flow across Indiana, and subsidence was shown exiting the state. Some middle level moisture was shown arriving within the Wabash valley.

Today and Tonight...

Models suggest the ridging over the plains will advance eastward, reaching the Great Lakes late tonight. NW flow is expected to remain in place today before shifting to the WNW tonight. Time heights and forecast soundings continue to show plentiful dry air within the lower and mid levels today and tonight. Models suggest that within the lower levels our weather continues to be controlled by the strong high pressure system to the east, with SE lower level flow today becoming light and southerly tonight. Thus mostly sunny skies will once again be expected today and mostly clear skies tonight. Look for highs at or above persistence.

Sunday and Monday...

Ridging aloft over the Great Lakes on Sunday will shift to the eastern Great Lakes and strengthen through Monday. This will shift the steering flow aloft to westerly and allow any forcing dynamics to push well north of Indiana. Strong upper level high pressure looks to set up over the southern plains and the Tennessee Valley. Within the lower levels strong high pressure settles east of the Carolinas, allowing warm and humid gulf flow to develop. Strong warm air advection will be in place on Sunday and Monday, leading to the arrival of warmer and more humid air as 850mb temps begin to surge toward 20C. This will result in highs into the 90s and heat as we end August, with mostly sunny days and mostly clear nights.

Tuesday and Wednesday...

Dry weather with continued heat is expected for the middle of next week. Strong upper level high pressure in place over the Ohio and TN River valleys will keep all forcing dynamics steered well north to the Great Lakes. Meanwhile within the lower levels, Indiana will be under the influence of high pressure centered off the Carolina coast. This will continue to allow hot and humid southerly flow to stream across Indiana. Forecast soundings on Tuesday suggest unreachable convective temperatures. On Wednesday, forecast soundings suggest slightly lower but still very high convective temperatures, with ample CAPE aloft. A diurnal shower or storm seems possible at this point, given the weaker cap. Highs in the middle 90s will be expected.

Thursday and Friday...

Models suggest strong ridging building aloft over the plains states. This will result in NW upper flow across Indiana and the Ohio valley. Some ridge riding forcing dynamics are suggested to spill across Indiana on Thursday night into Friday. Meanwhile within the lower levels, a frontal boundary that was previously across the Great Lakes is suggested to sag southward to Indiana and Ohio. Forecast soundings still show strong capping on Thursday, but that is suggested to weaken on Friday as possible forcing dynamics pass with very high pwats again. Thus at this point, chances for showers and storms on Thursday night and Friday are not out of the question. Again, look for very warm highs in the 90s.

AVIATION (18Z TAF Issuance)

Issued at 1254 PM EDT Sat Aug 29 2026

Impacts:

-None

Discussion:

High pressure is still present across the area keeping winds light. Winds will be variable at times, bue predominately out of the south this afternoon between 4-7kt. Sky cover will increase this afternoon due to an upstream system, expected a SCT to BKN deck around 20kft to continue into tonight.

Overnight, winds will back a little to the SSE. VIS impacts due to fog are not expected at this time, but cannot be ruled out at KHUF and KBMG.

IND WATCHES/WARNINGS/ADVISORIES

None.