135
FXUS63 KIND 041753
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
153 PM EDT Fri Sep 4 2026

.KEY MESSAGES...

- Heat Advisory in effect for all of central Indiana through late
  today with peak afternoon heat index values up to 108 degrees

- Heat Advisory extended into Saturday afternoon for the central
  and southwestern half of central Indiana.

- Isolated to scattered thunderstorms will be possible at times
  late today through Saturday.

&&

.DISCUSSION (This evening through Friday)...
Issued at 152 PM EDT Fri Sep 4 2026

Broad ridging centered over the Plains will amplify while slowly
drifting westward. This allows a trough over the northeastern US to
push into the Ohio River Valley, bringing an end to the current heat
wave. The ridge, temporarily shunted west, returns next week with
renewed heat and humidity. The secondary round of heat does not
appear to be as prolonged, with another trough arriving late next
week along with a reduction in temperatures. Scattered showers and
thunderstorms are possible with both troughs, though chances are
generally 40 percent or lower due to limited moisture and forcing.

Today through tonight

Temperatures are already into the mid 90s as of 1pm. Highs are once
again expected to reach the mid to upper 90s with dew points in the
low 70s. A Heat Advisory remains in effect as Heat Risk remains in
the extreme category with heat indices around 105 degrees.

A few isolated showers and thunderstorms are possible today but
overall the chances are low. Limited large-scale forcing and dryness
in the atmosphere will make cumulus growth difficult. ACARS
soundings show a very dry atmosphere along with a cap around 700mb.
Any attempts at convective initiation will be confined to subtle
features like gravity waves or horizontal convective rolls. Overall,
convective chances are very low today.

Saturday

The first of the aforementioned cold fronts arrives on Saturday from
the northeast. Atmospheric moisture is modeled to increase tomorrow
with better lapse rates. With the front acting as an initiating
force, our convective chances are a lot better compared to today.
Still, large-scale mid/upper-level forcing is displaced to the
northeast. Our convective chances are therefore dependent on the
front itself.

Two scenarios exist. First, the front initiates convection late
tonight or tomorrow morning, which then propagates southwestward
into the southwesterly low-level flow ahead of the boundary. This
would generally limit severe potential with the primary hazard
being heavy rainfall and localized flooding.

Second, the front enters central Indiana dry allowing daytime
heating to maximize. Increased instability along the front would
help initiate convection during the afternoon, which would propagate
southeastward in line with the shear vector. Bulk shear is not
excessive, but enough to allow for some storm-scale organization
into clusters or small bowing segments. Steeper lapse rates and
residual dryness may present a downburst or wind threat.

In the second scenario, maximized heating may necessitate the need
to expand the Heat Advisory. High-resolution guidance showing
scenario two also shows high temperatures once again in the mid 90s.
The only exception are locations to our northeast behind the front,
with FROPA some time around noon at the IN/OH line.

SUNDAY AND MONDAY

Northeasterly flow behind the cold front brings a cool and dry air
mass into the region. Temperatures fall back to near normal (low 80s
for highs and low 60s for lows) along with much lower dew points.
These conditions continue into early next week before the ridge
begins building back in by late Tuesday into Wednesday.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 152 PM EDT Fri Sep 4 2026

Impacts:

- Low chance of an isolated shower or thunderstorm today
- Better chances for showers and storms on Saturday
- Wind shift to northeasterly Saturday afternoon/evening

Discussion:

Mainly VFR conditions expected through the TAF period as a cold
front approaches from the northeast. Aside from a low (less than 15
percent) chance of a shower/storm today, quiet and hot weather is
expected.

Shower and storm chances as the front arrives on Saturday. The best
chance of storms is across the northeastern portion of central
Indiana from IND to BMG. Activity should be scattered in nature, so
a VCSH group was added to IND for now until timing can be refined.
MVFR or worse conditions possible in any thunderstorm along with
gusty winds.

The front sweeps through late Saturday afternoon or early evening. A
wind shift to northeasterly is anticipated. Speeds around 10kt with
gusts to as high as 20kt likely.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for INZ021-031-038-
040>042-049.

Heat Advisory until 8 PM EDT Saturday for INZ028>030-035>037-039-
043>048-051>057-060>065-067>072.

&&

$$

AVIATION...Eckhoff
DISCUSSION...Eckhoff