058
FXUS63 KIND 300349
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1149 PM EDT Sat Aug 29 2026

.KEY MESSAGES...

- 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 950 PM EDT Sat Aug 29 2026

Plentiful high clouds were across central Indiana this evening.
Showers/sprinkles that were across northeast Illinois/northwest
Indiana have continued to dissipate as they encounter drier air.
Even with the clouds, temperatures have cooled quickly, especially
in rural areas.

With the continued dissipation of the sprinkles, have left out any
mention of sprinkles for the remainder of the evening. Will have to
watch precipitation that is currently in Iowa, as well as for
developing sprinkles/light showers later tonight as some weak
isentropic lift moves across the area.

The northern forecast area would be the most likely to get any
sprinkles/light showers if the rain can survive the drier air here,
but for now believe odds are too low to mention in the forecast.

Lowered minimum temperatures some based on how fast temperatures
have already cooled even with the cloud cover.

&&

.DISCUSSION (This evening through Saturday)...
Issued at 250 PM EDT Sat Aug 29 2026

Deep high pressure across the southern Mississippi Valley, embedded
within an Omega Block pattern will keep broad ridging across the
eastern CONUS through much of the forecast period. Despite the
stagnate upper level pattern, the overall forecast will fluctuate
some as low level disturbances develop over the upper Mississippi
Valley this weekend into next week.

Initially, temperatures will remain seasonal as the ridge axis
remains to the west, thus highs today are expected to be in the low
to mid 80s with lows in the low 60s overnight. Also of note will be
an increase in cloud cover over the Ohio Valley today through
tonight. An 850mb jet will aid in maintaining convection as it moves
into the Great Lakes region. Upper level cloud debris will spill
over into the region, leading to 50-70 percent upper level cloud
cover by this evening. With the ridge still strongly established, a
majority of this convection will likely dissipate as it nears the
Indiana area, but a few isolated cells could reach NW portions of
central Indiana tonight. PoPs have been kept at 10 percent or lower,
but may warrant an increase if observations dictate.

The low level troughing associated with the 850mb jet will become
more diffuse as it pushes deeper into the upper high, but will still
have enough organization to push the low level flow towards
southerly. In return, temperatures will increase Sunday through mid
week, starting in the upper 80s and reaching the low to mid 90s by
Wednesday. This in combination with increasing dew points towards
the upper 60s to low 70s will push heat index values near 100 during
the middle of next week. Heat advisories will be likely over
portions of central Indiana next week, but there are still some
uncertainties with maximum daily temperatures (see next paragraph).

The main source of uncertainty will be the amplitude of the
aforementioned ridge over the lower Great Lakes and Ohio Valley. WAA
Sunday and Monday should aid in building the ridge some, but
diabatic processes from upstream convection and upper level water
vapor will mitigate pressure rises. Confidence in convection on the
northern periphery of the ridge is high, but how far south this area
of convection reaches is where confidence wanes. Currently the
expectation is for a majority of any precipitation next week to
remain north of the area, but the margin for error is small. Any
rainfall and associated cloud cover that does occur will limit
diurnal temperature gains, thus temperature gradients across the
state could be significant some days.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1149 PM EDT Sat Aug 29 2026

Impacts:

- None; VFR expected.

Discussion:

Mid and high level clouds will be expected to continue to stream
across the TAF sites overnight and on Sunday. Forecast soundings
continue to show dry lower levels through the next 24-36 hours.

Indiana will remain under the influence of high pressure in place
over the northeastern states, resulting in warm and humid southerly
flow within the lower levels on Saturday.

Clouds should prevent significant fog development overnight. However
a non zero chance for patchy fog still remains with any brief
clearing. confidence in this is too low to be worthy of a mention.

&&

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

$$

UPDATE...50
AVIATION...Puma
DISCUSSION...Updike