095
FXUS63 KIND 220112
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
912 PM EDT Mon Sep 21 2026

.KEY MESSAGES...

- Mainly cloudy and cool through midweek

- Dry and seasonable late week into the weekend with gradually
  warming temperatures

&&

.FORECAST UPDATE...
Issued at 912 PM EDT Mon Sep 21 2026

Surface analysis this evening shows strong, Canadian high pressure
in place over Ontario and Quebec. This high was influencing the
weather across the Great lakes and south to the Ohio River. Cool and
dry northeasterly flow was in place across Indiana, along with a
moderate pressure gradient. GOES19 shows abundant cloud cover across
Central Indiana and the region. The high to the north was resulting
in a cool NW dirty flow.

Overnight, very little change in the overall forecast. Clouds will
remain across the area amid the continued easterly flow. Forecast
soundings continue to indicate saturation within the lower levels
with a trapping inversion aloft. Thus cloudy skies will persist
through the night. The clouds and winds will keep temperatures from
falling too much as they reach the mid and upper 50s.

&&

.DISCUSSION (This Evening through Monday)...
Issued at 220 PM EDT Mon Sep 21 2026

Much cooler air has overspread the region in the wake of the
frontal passage late Sunday. Cloudy and breezy conditions are
expected through Wednesday as an upper low moves slowly through the
area. This feature will cutoff over the mid Atlantic by late
week...with much drier air being pulled south into the Ohio Valley
through the weekend.

Rest of Today through Wednesday Night

In the wake of the morning rain...a damp and dreary airmass remains
across central Indiana under a thick stratus deck and with breezy
northeast winds. 18Z temperatures were much cooler than what has
been experienced over the last several days with much of central
Indiana in the 60s.

There remain a few light showers or sprinkles over the southeast
half of the forecast area but the overall trend since the morning
has been for rainfall coverage to decrease extensively as the
frontal boundary that moved through the area Sunday afternoon and
evening has now moved well south into the Tennessee Valley.A few
light showers remain possible for the next few hours before
departing. Abundant moisture persists through the boundary layer
trapped beneath a stout inversion. Model soundings show the
inversion weakening slightly this evening which may be just enough
to allow for a brief period with breaks in the stratus deck. As the
inversion strengthens overnight however...expect the stratus deck to
thicken back up with ceilings lowering again into Tuesday morning.
Cannot entirely rule out a few sprinkles tonight but low confidence
in this occurring.

Clouds will remain on Tuesday as an upper low pivots into the region
from the northwest. The upper low will bring isolated light showers
across the far northeast portion of the forecast area otherwise
expect a continuation of weather today with thick stratus and cool
N/NE flow. The upper low will be slow to shift east of the area as
it becomes cutoff from the mean flow aloft well to the north of the
region. This will keep an abundance of clouds over most of the
forecast area through Wednesday as well with again a low chance for
a few showers across our northeast counties. More substantial breaks
in the clouds should come Wednesday night as ridging aloft slowly
spreads into the Ohio Valley from the west.

Temps...highs will not get out of the 60s this afternoon for much of
the forecast area...the coolest day since May 23. Expect similar
temperatures both Tuesday and Wednesday with highs ranging from the
mid 60s northeast to the lower 70s southwest. Lows will be in the
50s.

Thursday through Sunday

The aforementioned upper low will settle over the Mid Atlantic
region during the second half of the week. Cool E/NE flow and at
least some lingering cloud cover on the back side of the developing
cutoff low will maintain below normal temperatures Thursday with
highs ranging from the upper 60s to the mid 70s from northeast to
southwest. Ridging aloft will gradually shift into the Ohio Valley
with an axis of deepening subsidence advecting into the region from
the north. Under mainly clear skies...temperatures will recover back
to late September normals with highs warming into the mid and upper
70s by Sunday and perhaps into the lower 80s over parts of the
forecast area by Monday. The coolest night since the Spring comes
Friday night as lows in the mid and upper 40s will be common...with
temperatures recovering into the 50s for lows by the end of the
weekend.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 545 PM EDT Mon Sep 21 2026

Impacts:

- Mainly MVFR Cigs this period.
- Periods of IFR possible at BMG.

Discussion:

Cool, Canadian high pressure north of Central Indiana will continue
to provide a dirty NE flow of cooler air to the TAF sites. Forecast
soundings through the period keep saturated lower levels in place
with a trapping inversion aloft.

With little change in the pattern over the next 24-30 hours, MVFR
cigs will remain. A moderate pressure gradient across the area will
keep wind speeds around 10 knts. This will keep mixing going
overnight and should help to prevent fog.


&&

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

$$

UPDATE...Puma
AVIATION...Puma
DISCUSSION...Ryan