158
FXUS63 KIND 171344
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
944 AM EDT Fri Oct 17 2025

.KEY MESSAGES...

- Dry weather through Saturday morning

- Rain and thunderstorms expected late Saturday into Sunday along
  with occasional wind gusts of 30-40 mph.

- Isolated strong to severe wind gusts possible Saturday PM

- Turning cooler following frontal passage Sunday and Monday

&&

.FORECAST UPDATE...
Issued at 944 AM EDT Fri Oct 17 2025

Forecast is in good shape this morning, with just some areas of high
clouds moving across the area.

Quiet conditions will continue across central Indiana today with
upper ridging still in control of the weather. High clouds will be
increasing during the day, but even with these temperatures should
still top out in the 70s. Depending on the thickness of these
clouds, may have to tweak highs later, but for now no changes were
made to high temperatures.

&&

.SHORT TERM (Today and Tonight)...
Issued at 250 AM EDT Fri Oct 17 2025

Quiet early morning across central Indiana as the region remains
under the influence of high pressure. Despite light E/SE winds...
temperatures varied widely with ideal radiational cooling conditions
ongoing. 06Z temperatures ranged from the lower and mid 40s in some
of the typical cool spots across eastern portions of the forecast
area to the mid 50s near Indy and across the lower Wabash Valley.

The persistent ridging at the surface and aloft will remain
prevalent across the Ohio Valley through early Saturday. The
amplification of a stronger upper trough across the Canadian
prairies will serve to gradually flatten the ridge aloft as it
shifts east of the region to begin the weekend. This will be the
initial piece in the transition process to a strengthening surface
wave and cold front that will bring storms and wind to the region
late Saturday into Sunday.

Thin cirrus is already drifting into the forecast area early this
morning and that should only expand and thicken throughout the day
as progressively deeper moisture aloft advects into the Ohio Valley
ahead of the cold front that will move from the central Plains this
morning to the Missouri Valley by this evening. Winds will veer to a
S/SE direction today as the surface ridge shifts further away to the
east. With the approach of the aforementioned boundary...a
tightening of the surface pressure gradient will produce an increase
in winds up to 10 to 15mph for this afternoon before falling back
tonight. Mid and high clouds will remain tonight in advance of the
front as it moves closer to the forecast area by Saturday morning.
Model soundings and RH progs show lingering dry air below 500mb
tonight with most if not all of the rain holding off on reaching the
Wabash Valley until Saturday afternoon.

Temps...warm advection today will be counteracted by the increase
in high clouds which will likely produce highs similar to Thursday
in the low and mid 70s. Lows tonight will remain in the mid and
upper 50s over most of central Indiana.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 250 AM EDT Fri Oct 17 2025

Saturday through Sunday night...

The primary concern in the extended will be early in the period with
the potential for heavy rain across central Indiana and increasingly
windy conditions over the weekend. Some uncertainties in exact
details still exist, but guidance is becoming better aligned.

Models depict upper level ridging continuing to shift out of the
region early Saturday with a deep trough approaching from the west.
A strong jet streak on the upstream side of the upper trough will
allow for further amplification upon approach resulting in
strengthening upper level divergence. Surface cyclogenesis within
the Lake Michigan region is likely to occur with most guidance
suggesting a low developing near Indiana or Michigan. At the same
time, look for increasingly windy conditions due to a tightening
MSLP gradient and strong low-level jet. Strengthening S/SW flow will
also help to pull rich gulf moisture northward.

Strong dynamics and anomalous moisture streaming northward supports
the potential for widespread heavy rain across central Indiana. Most
ensemble guidance depicts 1-2 inches of rainfall which would be
beneficial given ongoing drought conditions. There is a low threat
for severe weather as low-level theta-e advection and cooling aloft
leads to a modest increase in instability. Slight uncertainty still
exists regarding storm mode depending on how the system evolves, but
favorable dynamics/shear supports at least an isolated damaging wind
gust threat. Forecast soundings do show some veering low-level
hodographs Saturday PM suggesting there may be an isolated tornado
threat. This will be monitored closely so check back for updates.

Precipitation chances begin to taper off Sunday into Sunday night
as drier air filters in behind the departing system. A tight MSLP
gradient along with shallow mixing into a strong LLJ will still
promote windy conditions. Outside of convection, occasional gusts
as high as 30-40 mph are possible.

Monday onward...

Quiet weather is expected to start the work week thanks to upper
ridging and surface pressure over the region. Models suggest another
system quickly moves in Monday night pulling another cold front
through. Limited moisture return is the main caveat which should
keep any rainfall amounts light. The front will provide another shot
of cooler and drier air. Expect near or slightly below normal
temperatures through midweek. Quiet weather continues through
midweek before another upper level impulse approaches late Wednesday
into Thursday. Rain chances are low once again with this feature due
to limited moisture return.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 547 AM EDT Fri Oct 17 2025

Impacts: None

Discussion:

Ridging at the surface and aloft will maintain its hold on central
Indiana through tonight even as moisture aloft steadily advects into
the region ahead of a cold front moving out of the Plains. Cirrus
will expand into the area and increase in coverage throughout the
day. S/SE winds will increase as well in response to a tightening
surface pressure gradient over the mid Mississippi Valley with 10-
15kts possible this afternoon. A brief higher gust is possible at
KLAF. High clouds will persist tonight with S/SE winds remaining at
5-10kts for much of the night.


&&

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

$$

UPDATE...50
SHORT TERM...Ryan
LONG TERM...Melo
AVIATION...Ryan