708
FXUS63 KIND 101352
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
952 AM EDT Thu Sep 10 2026

.KEY MESSAGES...

- Periodic showers with embedded thunderstorms today, especially
  across the southern half of central Indiana

- Briefly dry then scattered showers and storms return late Friday
  into Saturday

- Cooler through Friday with warmer temperatures returning this
  weekend into early next week

&&

.FORECAST UPDATE...
Issued at 952 AM EDT Thu Sep 10 2026

Central Indiana is in a break between areas of rain at the moment.
Regional radar shows more rain across central Illinois as well as
southwest Indiana, moving toward the forecast area.

Have lowered PoPs to reflect the current situation, but brought them
back up later this morning into the afternoon as the upstream rain
moves into the area.

Diminished sky cover is accompanying the break in the rain, so
lowered sky cover for a while this morning. Clouds will increase
again as the rain returns.

This break in cloud cover has allowed temperatures to rise faster
than expected, so bumped up hourly temperatures. Left high
temperatures alone for now, but may have to adjust them if the break
in the clouds lasts longer than expected.

&&

.DISCUSSION (Today through Wednesday)...
Issued at 233 AM EDT Thu Sep 10 2026

Showers and embedded thunderstorms will impact the region for much
of the day as a wave of low pressure rides along a frontal boundary
across the southern half of central Indiana. The front will shift
south and wash out by Friday but remnant moisture will interact with
a weak upper low to produce additional chances for rain across the
Ohio Valley Friday night and Saturday.

Upper ridging will flex back into the area this weekend and into
early next week with warm temperatures. A more organized threat for
rain and storms will accompany a cold front on Tuesday with cooler
air following for the second half of next week.

Today through Saturday

After a largely quiet first half of the night...scattered convection
was developing across the lower Wabash Valley early this morning
ahead of a cluster of storms moving east of KSTL. Temperatures at
06Z were in the upper 60s and lower 70s with patchy fog developing
as well.

The developing convection early this morning is being aided by
increasing warm advection and 850mb flow on the south side of a
quasi-stationary boundary located just south of I-70. Expect a
steady increase in coverage as an ongoing convective cluster over
southern Illinois shifts east through the predawn hours. With PWATs
near 2 inches currently across the southern portions of the forecast
area and a front that will move little over the next several
hours...storms will be efficient rainfall producers as they track
across the southern tier of counties from Vincennes to Seymour
through daybreak with lighter rainfall rates further north.

The first area of shower and storms will move east but once the
front pushes further south...winds will shift to northerly. of the
forecast by late morning but will likely be followed by a second
cluster currently across eastern Kansas and western Missouri and
poised to track into the southern half of the forecast area this
afternoon. The arrival of an upper wave from the northwest will
buckle heights aloft and should allow for the frontal boundary to
resume southward progression during the afternoon. The heaviest
rainfall rates with the afternoon storms may just graze far
southern counties and focus more across far southern Indiana into
Kentucky where a more unstable airmass will reside.
Regardless...rain chances will linger for much of the day with an
abundance of lower clouds.

Clouds will diminish from the north tonight as weak high pressure
and deeper subsidence expand into the area. Patchy fog may again be
a factor for early Friday with near calm winds even as drier air
advects into the region. The aforementioned frontal boundary will
wash out south of the Ohio River on Friday leaving an axis of
remnant moisture. As a developing upper low lifts into the mid
Mississippi Valley late Friday...the moisture will be pulled back
north into the area with scattered showers and storms impacting the
southeast half of the forecast area in particular Friday night into
Saturday as the upper low pivots across the region.

Temps...clouds and rain today will keep temperatures closer to early
September normals in the upper 70s and lower 80s with similar
readings for Friday as well. The resumption of return southerly flow
for Saturday will bring a warmer and subtly more humid airmass back
into the area with mid 80s.

Saturday Night through Wednesday

The deeper moisture plume will shift east of the region Saturday
night as ridging aloft expands back north for late weekend. This
will stall a weak frontal boundary to our north over the lower Great
Lakes before lifting back north as a warm front early next week in
response to low pressure developing over the High Plains. This will
allow for a brief return of a hotter and more humid airmass with
highs climbing back to near 90 degrees Monday and Tuesday across the
southern half of the forecast area.

The aforementioned surface low will track into Ontario on Tuesday
pulling a cold front into the region with a better chance at showers
and storms. Model trends are now supporting the boundary becoming
nearly stationary across the Ohio Valley through the middle of next
week as it runs into the retreating upper level ridge to the south.
The boundary may linger until a much stronger cold front running in
tandem with a sharp upper level wave dives through the area late
next week. In the wake of this frontal passage...the first
opportunity for a cooler early Fall airmass is becoming increasingly
likely for the region by next weekend.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 549 AM EDT Thu Sep 10 2026

Impacts:

- Occasional showers with embedded thunder today
- MVFR ceilings possible late morning through the afternoon
- Patchy fog early Friday

Discussion:

Showers are moving across central Indiana early this morning with
thunderstorms just south of KBMG. This area of rain will move east
of the terminals this morning with an additional rain and embedded
thunder set to spread into the area for the afternoon. Showers will
linger through late day but gradually sink south of the terminals
with a frontal boundary this evening.

Model soundings and RH progs both highlight an expansion of MVFR
stratus later this morning that will linger into the afternoon with
showers. Lower clouds will move out this evening with ceilings
lifting tonight as drier air advects in from the north. Winds will
be light and variable for much of the day then shift to light
northeast tonight. Patchy fog is likely to develop in the predawn
hours on Friday.


&&

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

$$

UPDATE...50
AVIATION...Ryan
DISCUSSION...Ryan