791
FXUS63 KIND 241617
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1217 PM EDT Mon Aug 24 2026

.KEY MESSAGES...

- Cooler and less humid weather expected through Tuesday

- Patchy fog through 8am this morning with additional fog
  development possible late tonight

- Scattered showers and storms possible Wednesday evening into
  Thursday

&&

.FORECAST UPDATE...
Issued at 900 AM EDT Mon Aug 24 2026

Beautiful start to the morning across central Indiana with the
patchy fog quickly diminishing. 13Z temperatures were generally in
the upper 50s into the 60s.

Forecast is in excellent shape for the remainder of the day with
high pressure across the region. Expect scattered diurnal cu
formation for the afternoon as low level mixing takes place but
sunshine will be abundant today. Winds will remain out of the
northwest veering to northerly by late day as the center of the high
remains to our west.

Low level thermals support highs from the upper 70s to the lower 80s
from northeast to southwest for most of the forecast area. Zone and
grid updates out.

&&

.DISCUSSION (Today through Sunday)...
Issued at 301 AM EDT Mon Aug 24 2026

Today through Tuesday night...

Patchy fog has developed across central Indiana this morning due to
very light winds and mostly clear skies. Current observations show
this fog has mostly developed in climatologically favored locations
in valleys or near rivers. Look for this to become more common in
favored locations through daybreak before then quickly mixing out
after sunrise.

Mostly quiet weather conditions are expected early this week with
surface high pressure across the region. Aloft, upper troughing
shifts east into Tuesday while ridging builds in. This should allow
for a slight moderation in temperatures, but seasonably cool
temperatures will persist given negligible thermal advection. Highs
will generally range from the mid 70s to low 80s.

Very light winds and mostly clear skies again tonight into Tuesday
morning will promote patchy fog development. Any fog that develops
should quickly mix out in typical diurnal fashion. Surface high
pressure begins to shift east late Tuesday allowing for surface flow
to become more southerly late overnight.

Wednesday through Sunday

A weakening upper level low riding overtop of the western ridge will
drop into the upper Midwest early Wednesday before becoming absorbed
by a broader long wave trough that will amplify across the eastern
half of the country for late week. Low pressure and an associated
cold front running in tandem with the upper wave will track across
the Ohio Valley Wednesday evening through early Thursday in a
progressively weakened condition as stronger forcing aloft is lost.
There will be enough moisture and instability along and immediately
ahead of the frontal boundary for scattered convection with the
front clearing the forecast area during the day Thursday. Isolated
convection is possible on Thursday across east-central IN before the
front moves out.

A few strong storms cannot be ruled out Wednesday evening into
Wednesday night as guidance depicts moderate instability ahead of
the approaching front along with slight enhancement of mid-upper
level flow from the approaching wave aloft. Confidence remains low
due to varying model solutions, but trends will continue to be
monitored. These details should become more clear once guidance is
better aligned.

High pressure will reestablish in the wake of the frontal passage
drifting slowly east through the Great Lakes into Saturday. This
bring another multi day stretch of dry weather with seasonable
temperatures as highs will focus largely in the low to mid 80s. The
ridge will flatten to the west over the weekend opening the
possibility for convection to impact the region by late weekend into
early next week as multiple waves ride along in the predominantly
zonal flow aloft. Temperatures will also rise back into the mid and
upper 80s by the end of the forecast period with an uptick in
humidity levels.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1217 PM EDT Mon Aug 24 2026

Impacts:

- Fog likely at the outlying TAF sites late tonight into Tuesday
  morning, especially at KLAF

Discussion:

Mainly VFR conditions will continue across central Indiana into
Tuesday as high pressure resides over the region. Scattered diurnal
cu will expand through the afternoon before diminishing near or just
after sunset with cirrus drifting across central Indiana overnight.
Fog will once again develop at the outlying terminals late tonight
and through daybreak Tuesday...most notably at KLAF where an
extended period of under 1SM visibilities is possible in the predawn
hours.

N/NW winds remain at or below 10kts through the afternoon then
become light and variable tonight. Winds will veer to southeast on
Tuesday.

&&

.IND WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

UPDATE...Ryan
AVIATION...Ryan
DISCUSSION...Ryan/Melo