643
FXUS63 KIND 301345
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
945 AM EDT Sun Aug 30 2026

.KEY MESSAGES...

- Hot and more humid Weather will be arriving through Tuesday.

- Thunderstorms will be possible late next week into the weekend.

&&

.FORECAST UPDATE...
Issued at 944 AM EDT Sun Aug 30 2026

Latest satellite observations this morning depict extensive mid-high
clouds across the northern half of Illinois and Indiana. These
clouds are associated with an upper impulse traversing the region.
There have been a few sprinkles reported at times across Illinois
with moisture streaming in aloft and weak forcing from the
impulse, but surface ridging and residual subsidence-induced dry
air has mostly limited any measurable precipitation from reaching
the ground.

Dry air in the low-levels will keep central Indiana mostly dry
today, but low 20 percent rain chances were included in the latest
updated for far north/northwestern counties today as the subtle
upper level wave moves through. Mid to high clouds will limit
daytime heating slightly, mainly across the northern half of the
area. Southwesterly flow should still help promote a warming trend
today with temperatures in the mid 80s to low 90s.

&&

.DISCUSSION (Today through Saturday)...
Issued at 246 AM EDT Sun Aug 30 2026

Surface analysis early this morning shows high pressure east of the
middle Atlantic States, allowing a warm and humid southerly flow
across Central Indiana. Water vapor shows a stream of Pacific
moisture pushing across the Rockies to a ridge axis over the upper
midwest before spilling southeast across Indiana and the eastern
Great Lakes. It was this stream of upper moisture that was providing
mid and upper level cloud cover across Central Indiana and points
north. HRRR profiles show plentiful dry air within the lower levels.
Dew points were creeping higher, into the 60s.

Today and Tonight...

The models continue keep the stream of upper level Pacific moisture
streaming across a ridge axis over the Great Lakes, as upper level
high pressure remains parked over TN/AR. A thermal ridge within the
lower levels is suggested to set up over the upper midwest, as warm
air advection continues across Indiana. Surface high pressure to the
east looks to continue to control our lower levels, providing warmer
and more humid flow. Still, forecast soundings today and tonight
suggest abundant dry air within the lower levels. Thus we will
expect a warmer day with ongoing warm air advection along with
passing mid to high clouds through tonight.

Monday and Tuesday...

Forecast soundings on both Monday and Tuesday continue to suggest
plentiful dry air within the lower levels along with ongoing warm
air advection still in place. 850mb temps are suggested to rise to
around 22C, bringing very warm temperatures for early September.
Convective temperatures in the 100s are suggested also, thus no CU.
Within the upper levels the strong upper level high pressure system
will begin to surge northeast somewhat, driving any forcing dynamics
north, across the Great Lakes. Thus mostly clear skies will be
expected with hot high temperatures in the 90s.

Wednesday through Thursday...

Confidence continues to be high for hot and humid weather at the end
of this workweek continuing into next weekend.

The upper pattern on Wednesday into Thursday suggests strong upper
level high pressure over the Tennessee and Ohio river valleys with
the upper flow streaming across the Great Lakes with some embedded
waves within that flow. A thermal ridge and frontal boundary looks
to be draped across the Great Lakes at that time, keeping Indiana
within the warm sector. Forecast soundings at this point show
convective temperatures in the mid 90s, which can be reached. Steep
lapse rates are also suggested, thus isolated diurnal convection
cannot be ruled out either. However the main story will be September
heat with highs in the low to mid 90s and high heat index values.
Heat Advisories will be possible in the week ahead.

Friday and Saturday...

The ridging over the upper midwest is suggested to become sharper on
by Friday and Saturday. This will allow for NW flow to develop across
Central Indiana, also introducing a possible pattern of placing us
on the periphery edge of a ring of fire. The previous warm front
and thermal ridge to the north is suggested to sag southward across
Indiana and this may cause an extra convection triggering feature.
Forecast soundings suggest plentiful CAPE with steep lapse rates on
Friday and Saturday. Thus pops day will continued to be needed.
Caveats include the frontal boundary sagging south of Central
Indiana on Saturday, resulting in cooler northerly flow while
introducing subsidence within the column. Furthermore, possible
clouds along the front may prevent max heating, keeping temperatures
cooler. Overall, some pops should be included here with highs above
seasonal normals.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 620 AM EDT Sun Aug 30 2026

Impacts:

- None; VFR expected.

Discussion:

Overall very little change in the ongoing forecast.

Mid and high level clouds will be expected to continue to stream
across the TAF sites Today. Forecast soundings continue to show dry
lower levels through the next 24-36 hours. Although there are some
radar returns over northern IL and Northern Indiana, much of this is
expected to stay north of the TAF sites or remain virga falling from
high bases through dry lower levels.

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 today.


&&

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

$$

UPDATE...Melo
AVIATION...Puma
DISCUSSION...Puma