922
FXUS63 KIND 241738
AFDIND

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

.KEY MESSAGES...

- Cooler and less humid weather expected through Tuesday

- Scattered showers and storms possible Wednesday evening into
  Thursday

- Dry weather returns for late week into the weekend

- Hotter and more humid air arriving Sunday into early next week

&&

.DISCUSSION (This Evening through Monday)...
Issued at 138 PM EDT Mon Aug 24 2026

Dry and pleasant weather continues through midweek as central
Indiana resides under the influence of high pressure. Deep upper
level ridging will remain tethered for the next several days over
the Intermountain West with a largely dry northwest flow over the
region. The passage of a cold front late Wednesday into Thursday
will present the primary convective risk through the forecast
period. The expansion of upper level ridging by late weekend will
bring the return of a hotter and more humid airmass to the Ohio
Valley into early next week.

Rest of This Afternoon through Wednesday

Another beautiful late summer afternoon in progress as the region
resides under high pressure. A scattered diurnal cu field has
developed with generally light northwest winds. 17Z temperatures
were in the 70s with comfortable humidity levels.

A superb next 48 hours through Wednesday afternoon is in store as
the surface high drifts slowly through the region and remains the
primary influence across the Ohio Valley. A brief period with
increased mid and high clouds may graze the lower Wabash Valley this
evening as a weak upper level wave passes through the lower Ohio
Valley. Otherwise partly cloudy skies are expected through Wednesday
with scattered cu developing each afternoon and diminishing near or
just after sunset. With mainly clear skies and light winds...patchy
fog will be likely late tonight and Tuesday morning in the favored
areas in valleys and near streams.

As return flow develops from the southwest an increase in low level
moisture will lead to an increase in cu coverage Wednesday afternoon
in advance of a cold front approaching from the northwest. The cold
front will approach in tandem with an upper level low rounding the
crest of the ridge aloft to our west and dropping across the Great
Lakes on Wednesday. Convection will generate to our north by late
day in advance of the cold front.

Temps...low level thermals support highs largely in the low and mid
80s Tuesday and Wednesday with the warmer day on Wednesday courtesy
of the advent of the southwesterly flow. Another night with lows in
the 50s tonight will be followed by a moderating trend back into the
60s by midweek.

Wednesday Night through Monday

The aforementioned upper level low will become absorbed  becoming
absorbed by a broader long wave trough Wednesday into Thursday 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 night and
early Thursday in a progressively weakened condition as stronger
forcing aloft is lost. Stronger convection that develops over lower
Michigan and northern Illinois by late day Wednesday along the
boundary may make it into far northern counties late Wednesday night
in a weakened state before coverage drops off in the unfavorable
predawn hours of Thursday with minimal instability available. The
front will progress through the forecast area Thursday with
scattered redevelopment over southern parts of the forecast area in
the afternoon before clearing the area late day.

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.
Return flow develops on Sunday as the high shifts off to the east...
with an increase in temperatures and humidity levels by early next
week as the ridge aloft to the west expands towards the Ohio Valley.
The increase in moisture and instability will lead to an
introduction of isolated to scattered mainly afternoon and evening
convection. Highs in the upper 80s and lower 90s are expected by
Sunday and Monday with max heat indices into the upper 90s.

&&

.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.

&&

$$

AVIATION...Ryan
DISCUSSION...Ryan