545
FXUS63 KIND 220115
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
915 PM EDT Thu Aug 21 2025

.KEY MESSAGES...

- Temperatures near to below normal throughout the next week with
little to no chance for rain until the end of the month

&&

.FORECAST UPDATE...
Issued at 915 PM EDT Thu Aug 21 2025

No major changes needed to the ongoing forecast with conditions
generally evolving as expected. The main forecast challenge for the
rest of the night will be tracking the potential for fog. Winds will
remain in the 3-7 mph range which will help to limit the coverage of
fog to the more sheltered and favored fog formation zone like river
valleys but expect greater coverage Friday morning compared to what
occurred Thursday morning due to the decreasing coverage in clouds.
Some of the hi-res models are starting to pick up on the better
chances, but think coverage will be greater than model guidance
currently shows. Overnight lows in the low to mid 60s still look
reasonable with some localized cold spots likely to fall into the
upper 50s, especially across north central Indiana.

&&

.SHORT TERM (This evening through Friday)...
Issued at 221 PM EDT Thu Aug 21 2025

Relatively cool and cloudy weather persists over Central Indiana
today as a strong low level inversion keeps moisture trapped near
the boundary layer. Clouds have finally began to lift and break up
some due to just enough daytime heating, but still expect mostly
cloudy skies through at least this evening.

For tonight, a better chance for fog exists as the center of high
pressure settles in over the region with clearing skies and lighter
winds. Best chance for any fog formation will be after the 2am
timeframe through around sunrise in low lying, wind sheltered areas
and the Wabash River Valley. Any areas where cloud cover lingers
overnight may not see fog, rather lower stratus instead. Any fog
should dissipate within the 8-9am timeframe. Dew points and boundary
layer RH are still relatively high, so do not expect a large diurnal
range in temperatures with lows in the low 60s.

Another comfortable August day in the forecast for tomorrow as high
pressure remains the dominant weather influence locally. Cloud cover
should be more scattered in nature resulting in more sunshine and
better boundary layer heating than the past few days. A strong low
level subsidence inversion will hold steady overhead, limiting
deeper mixing during peak heating of the day, but with more sunshine
highs should be able to reach the 80 degree mark for most areas.

&&

.LONG TERM (Friday night through Thursday)...
Issued at 221 PM EDT Thu Aug 21 2025

A taste of cool, early fall-like weather is expected to start on
Sunday through Thursday.

Saturday and Saturday Night...

Indiana will still be in the warm sector for much of Saturday as low
pressure pushing east across Ontario keeps southwesterly flow in
place ahead of an approaching cold front. Forecast soundings on
Saturday remain dry as southerly gulf flow has failed to develop
ahead of this system. Thus for now, models indicate that this will
be a dry day and night as the cold front passes. Highs in the 80s
will still be expected within the warm sector on Saturday, with some
increasing clouds on Saturday afternoon and Saturday night with the
passing front.

Sunday through Thursday...

Models show strong ridging developing aloft next week over the
Rockies in response to a deep upper low and strong trough moving
through eastern Canada. This places in a favorable position for
subsidence, on the lee side of the ridge to the west, with continued
cooler, continental and Canadian air flowing into the Ohio valley.
Models suggest there could be a few upper disturbances passing
within the NW flow aloft on Monday and Tuesday, but moisture will be
a problem. Any coverage at this point appears limited and not worthy
of mention in the forecast at this time. Within the lower levels,
all of the subsidence will allow the development of a strong surface
high pressure system settling over the plains states. Again, with
will keep cooler NW surface flow across Indiana. 850mb temps are
expected to fall to 6-9C through the course of the next work week.
This will allow for highs to only reach the 70s. Furthermore, dew
point temperatures will fall to the 50s and even some 40s degree
values, resulting in super comfortable, not humid weather.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 646 PM EDT Thu Aug 21 2025

Impacts:

-Patchy fog towards daybreak will bring periodic MVFR to IFR vsbys.

Discussion:

Cloud coverage will gradually decrease through the night with a
return of patchy fog expected after 09Z tomorrow through around 14Z.
Confidence is highest at LAF and HUF with lower chances at IND and
BMG. There could be a brief IFR ceiling during the fog, but
expectations are that the fog will be very shallow and shouldn`t
impact cigs. Clouds will then lift to around 025-035 and remain
scattered through the rest of the day. Winds will remain
northeasterly at 4-10kts through the TAF period.


&&

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

$$

UPDATE...White
SHORT TERM...CM
LONG TERM...Puma
AVIATION...White