568
FXUS63 KIND 120646
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
246 AM EDT Sat Jul 12 2025

.KEY MESSAGES...

- Localized flooding and isolated strong to severe wind gusts
  possible this weekend

- Not as warm Sunday, not as humid Sunday night...with otherwise
  humid and very warm/marginally hot conditions most of next week

- Daily chances of showers/t-storms next week for mainly Tuesday and
  onward...isolated downpours/localized flooding possible

&&

.SHORT TERM (Today and tonight)...
Issued at 246 AM EDT Sat Jul 12 2025

Early This Morning...

Outflow from an old MCS was moving toward central Indiana, with
brief convection still forming just behind it. Plentiful instability
remains across central Indiana with temperatures still in the middle
70s to lower 80s at 06Z.

Will have some PoPs in the western forecast area early this morning
for this boundary as it moves into the area. Wind gusts have
diminished across Illinois as the boundary moves east, so feel it
will run out of steam in the western forecast area. Larger scale
forcing will remain west of central Indiana early this morning and
shouldn`t be a factor with this.

Will keep a close eye on it though and adjust PoPs as necessary. Not
expecting any severe weather given the weakening nature of the
boundary.

Today into Early Evening...

There will be some clouds this morning around from the old
convection, and the old outflow boundary will be lingering in
central Indiana. Believe that convection from this boundary will
have dissipated by 12Z. Will start the morning out dry, but will
have some small PoPs develop as heating occurs and potentially
interacts with this boundary.

The primary show will be this afternoon into early evening though as
a surface trough moves in from the northwest and provides broader
forcing. Some upper energy will also help provide forcing. Moisture
will be plentiful with precipitable water values around 2 inches.

Clouds thinning this morning will allow enough sunshine to boost
temperatures into the upper 80s and lower 90s for highs. This and
the moisture will bring good instability to the area. However, deep
layer shear isn`t good. The instability should be enough though for
the threat of some damaging wind gusts with storms this afternoon
into early evening though.

The uncertainty of the influence of the old outflow boundary along
with uncertainty in initial cloud cover makes confidence lower than
desired for this forecast. Still feel though that forcing and
moisture will be enough for likely category PoPs for much of the
area.

The highest PoPs, and the best chances for any severe storms, will
be across roughly the southeast half of central Indiana. This area
should be east of the initial old outflow and should see the most
sunshine/highest instability.

The strongest storms look to be east of central Indiana by around
00Z (8 PM EDT).

Mid Evening through Overnight Tonight...

Chances for showers and storms will diminish from west to east
tonight as the surface boundary moves east. Will have mainly chance
PoPs, lowering as the night progresses.

Lows will be in the upper 60s and lower 70s.

&&

.LONG TERM (Sunday through Friday)...
Issued at 246 AM EDT Sat Jul 12 2025

Sunday through Monday...

A second, less-impressive day of convection is possible Sunday as
the cool frontal zone slowly progresses southward through central
Indiana. While a strong storm or two cannot be ruled out, organized
strong/severe storms are not expected.  Greater threat will be
precipitable water values in excess of 2.00 inches over southern
counties combining with lift along the boundary to promote a few
slow-moving late day downpours and possibly localized flooding.
Overall lower instability and lackluster lapse rates are expected to
thwart any severe potential, although modest/noteworthy 30KT of bulk
shear could help a couple cells produce stronger gusts over southern
zones.

Expect a subtle drop in humidity Sunday night when light northwest
surface flow drops dewpoints below 65F for several hours near/north
of I-70.  Rain-free conditions Sunday night will continue into early
Tuesday for most locations, although a couple stray showers cannot
be ruled out late Monday south of I-70.  The workweek should start
with humid, but non-oppressive conditions...and very warm, yet sub-
90 degree readings.

Tuesday through Friday...

A quasi-stationary front is expected to set-up from weak surface low
pressure in the central High Plains east-northeastward into the
Great Lakes.  While noticeably cooler conditions will be taking
place over the Upper Midwest and into southern Canada, low
confidence in any taste of autumn making it into the Hoosier state
during the long term period.  The subtropical upper ridge will make
a weak attempt to build northward from the southeastern CONUS into
the Midwest, but suspect any string of 90+ degree days should be
held to the Ohio Valley and south.  In between these features, the
CWA will see more of the very warm/marginally hot and humid pattern,
with daily chances for at least diurnally-driven showers/t-storms.
The location of the boundary to our north should influence location
and coverage of daily convection.  Overall higher precipitable water
values around 2.00 inches will promote a few torrential downpours
and potential isolated flooding.

Low confidence due to model inconsistency in when any milder air
from the north may finally make it to the local region late next
week...although unlikely the period ends on a hot note. For the long
term, afternoon maximum heat indices are expected to peak in the mid-
 to upper 90s on Tuesday through Thursday, with isolated low 100s
values possible over southern Indiana.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 133 AM EDT Sat Jul 12 2025

Impacts:

- Low chance of convection and a wind shift early for western sites

- Scattered to numerous storms are expected Saturday afternoon into
  Saturday evening

Discussion:

There is lower confidence on the specifics of the convection
forecast with this TAF set. Weakening convection with an outflow
boundary is moving into central Illinois at this time. Outflow may
survive into the western sites, so added a PROB30 for this.

Otherwise, VFR conditions are expected through much of the period. a
surface front will move in Saturday afternoon and should bring
scattered to numerous convection. However, influence from the
current dying convection could influence the timing and coverage,
leading to the higher uncertainty. Kept the PROB30s for now.

Some wind gusts around 20kt are likely Saturday afternoon.


&&

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

$$

SHORT TERM...50
LONG TERM...AGM
AVIATION...50