textproduct: Indianapolis

KEY MESSAGES

- Areas of fog early this morning...especially in low-lying areas - Isolated/scattered showers and a few t-storms are possible late Friday night...and again Saturday afternoon, mainly east

- Milder/less humid Saturday night through Tuesday...highs mainly 75- 80F, lows mainly 55-60F.

FORECAST UPDATE

Issued at 953 AM EDT Fri Aug 21 2026

A couple of small patches of fog continue to mix out this morning as heating begins in earnest. Obs trends and latest near term guidance suggests we're a bit low on high temperatures this afternoon, and have bumped maxes up a degree or two across the board.

Aside from some fair weather cumulus, expect minimal cloud cover through the day under high pressure. Winds will be relatively light and occasionally variable as the high moves overhead.

DISCUSSION (Today through Thursday)

Issued at 309 AM EDT Fri Aug 21 2026

Areas of reduced visibility in fog and patchy dense fog will dissipate early this morning amid light and variable winds. Lingering stratus should transition to diurnal cumulus by midday. Seasonably strong surface high pressure sliding east into New England...will drag its weaker southwestern corner/axis across central Indiana. Meanwhile a mid-level weakness will round the southern side of a Canadian upper trough into the Midwest... with dewpoints overall trending higher to end the workweek. H850 temperatures around only 15 degrees Celsius will allow for near to slightly below normal high temperatures in the low to mid-80s, although this milder trend will still feel summery by late day given the increasing humidity.

Increasing upper troughing from Great Lakes to eastern North America this weekend through the long term will suppresses hot/humid subtropical ridge well to our south/west...with an overall noticeably drier pattern through at least next Tuesday....although lower chances of RWs are on the table for late tonight, and more so eastern counties Saturday afternoon...ahead of more September-like conditions early next week.

AVIATION (12Z TAF Issuance)

Issued at 706 AM EDT Fri Aug 21 2026

Impacts:

- Brief morning fog at the outlying sites; additional fog possible tonight

Discussion:

Surface high pressure over the area will lead to relatively light and occasionally variable winds much of the period. The high has also set the stage for some fog this morning, which will mix out in typical diurnal fashion within the first hour or two of the period.

Few to scattered diurnal cumulus clouds can be expected this afternoon, which will dissipate this evening. A gradual increase in mid and high cloud is expected late as an upper level wave moves into the region.

Additional fog is possible tonight, which may be dense in spots, but uncertainty is too high to get into details this package.

IND WATCHES/WARNINGS/ADVISORIES

None.