textproduct: Indianapolis

KEY MESSAGES

- Dry weather with a warming temperature trend continues through the weekend.

- Hotter and more humid air arrives Sunday into early next week.

FORECAST UPDATE

Issued at 955 AM EDT Thu Aug 27 2026

Fog continues to gradually mix out this morning, with most lingering fog (and some stratus) across the far southern forecast area. Adjusted sky cover for this stratus this morning.

Otherwise, a scattered to broken cumulus field will develop today, making skies partly cloudy. Forecast highs look reasonable given the expected sky cover.

Instability this afternoon may lead to an isolated shower, but if it occurs coverage is expected to be low enough to not mention. Will continue to monitor.

DISCUSSION (Today through Wednesday)

Issued at 228 AM EDT Thu Aug 27 2026

Surface analysis early this morning shows low pressure in place over Ontario with a trailing cold front across Lake Huron to Central Indiana and Western KY. GOES19 shows thunderstorms ahead of the front had advanced to the Ohio river while the rest of the forecast area remained clear. Dew points across the area still remained rather high, in the middle 60s, and some fog was beginning to form. Aloft, water vapor shows strong ridging in place over the western CONUS, and a deep trough over Ontario and the Great Lakes, resulting in a highly amplified flow. Northwest flow and subsidence was found across Indiana.

Today...

Models show the strong ridging over the Rockies continuing to slowly build eastward. This will keep the northwest flow and lee side subsidence in place, allowing strong surface high pressure to the northwest to build across Indiana today. Forecast soundings show dry air within the mid levels today, but do show signs of afternoon CU development. Thus after morning fog burns off, mostly sunny skies will be expected followed by a partly cloudy afternoon. Look for highs in the lower to middle 80s.

Fog development will continue to need to be watched over night and should dense fog become widespread, an advisory may be needed.

Tonight through Saturday...

Through Saturday, the upper ridging to the west continues to slowly nudge eastward, keeping Central Indiana under northwest flow aloft and ongoing subsidence. Mid level RH is very indicative of this, showing low RH across the region through Saturday. Forecast soundings tonight through Saturday show a very dry column with unreachable convective temperatures. Thus mostly sunny days and mostly clear nights will be expected. As the associated high pressure system drifts east of Indiana by Saturday, southerly return flow will begin to develop. Thus expect a warming trend in daily high temperatures, reaching the mid to upper 80s by Saturday.

Sunday through Wednesday...

Hot weather looks to appear for the end of August and early September across Central Indiana. Models are suggesting a strong area of upper level high pressure setting up over the deep south, with an associated ridge axis pushing north across the Great Lakes. This looks to keep the main steering flow aloft well north of Central Indiana, keeping any forcing dynamics out of our area. Strong surface high pressure looks to set up over the southeastern states extending east to Bermuda. This will result in a steady flow of hot and humid air across Central Indiana. Surface temps are suggested to easily reach the 90s each day with dew points surging into the 70s. Early forecast soundings suggest 700mb temps in excess of 12C, resulting in a cap with convective temperatures over 100F. Thus at this point, diurnal storms are not in play, but this could change as things progress and the eventual flow aloft.

AVIATION (18Z TAF Issuance)

Issued at 1253 PM EDT Thu Aug 27 2026

Impacts:

- MVFR fog expected at most sites overnight, IFR and worse possible.

Discussion:

Scattered to broken VFR cumulus will continue through the daylight hours before dissipating as heating is lost this evening.

Light winds and clear to mostly clear skies overnight will likely lead to more fog development. Sunshine during the day today will help dry things out, which should help conditions be not as bad as last night/early this morning at most sites. However, IFR and worse are possible. (KIND should remain VFR)

Fog will mix out early Friday, then a few cumulus will pop up.

IND WATCHES/WARNINGS/ADVISORIES

None.