503
FXUS63 KIND 101808
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
208 PM EDT Sun Aug 10 2025

.KEY MESSAGES...

- Hot and humid conditions again Monday with most areas remaining dry

- Daily chances for isolated to scattered storms Tuesday through the
  weekend

- Muggy conditions last through next weekend and likely beyond

&&

.SHORT TERM (This evening through Monday)...
Issued at 208 PM EDT Sun Aug 10 2025

Rest of This Afternoon...

Very warm and humid conditions will persist this afternoon.
Satellite shows a cumulus field across central Indiana early this
afternoon, with some towering cumulus visible in a few areas.

Mid level temperatures should be warm enough to keep most convection
at bay, but a few isolated showers or storms popping up in the
instability cannot be ruled out. An outflow boundary across central
Illinois should stall/dissipate before reaching central Indiana.

Still believe that rain coverage this afternoon will be below
mentionable levels (less than 15 percent), but will monitor in case
this changes.

Tonight...

The cumulus field will dissipate this evening, but a few areas of
cirrus may move in at times from convection to the west.

Later tonight, leftover clouds from convection or from old
boundaries from convection could reach the northwest forecast area.

Some models do show some convection surviving and sneaking into the
northwest, but feel that given the time of day and the upper high
nearby, odds of any rain making it are low. Will have slight chance
PoPs in the far northwest late tonight, with low confidence.

Patchy ground fog may develop once again overnight. Lows will be
around 70.

Monday...

Monday will continue to see similar conditions to previous days. The
main difference is that old boundaries from convection to the west
could be across portions of northwest central Indiana. This may be
enough to allow enough isolated convection to develop for some
slight chance PoPs in the northwest.

Elsewhere, again, cannot rule out isolated convection given the
instability, but warm mid level temps will help keep these below
mentionable PoP thresholds.

Humid conditions with highs around 90 can be expected.

&&

.LONG TERM (Monday night through Sunday)...
Issued at 208 PM EDT Sun Aug 10 2025

Monday Night Through Thursday.

The main focus for the early portions of the long term period will
be tracking rain and storm chances as a frontal boundary pushes
through the state. Latest model guidance remains on track with
previous runs with the timing of the frontal passage looking to be
late Tuesday into early Wednesday with the best rain chances just
ahead of the front. There are some minor differences in timing
between the deterministic models but overall confidence is fairly
high in the timing. A lack of strong northwesterly flow behind the
front will limit the impacts and only bring a few degrees in relief
from the heat with expected highs in the low 90s ahead of the front
and mid to upper 80s towards Wednesday and Thursday.

The primary threat with this frontal passage will be locally heavy
rain. With little to no shear and with the expected timing being
predominately during the overnight, the severe threat looks minimal.
With a multi-day stretch of dry weather, the antecedent conditions
won`t be as favorable for flash flooding but with weak steering
flow, there is a potential for very high rain rates of over an inch
per hour to occur for several hours. The NAM is trying to hint at
localized areas of heavier rain, but will need additional higher
resolution models to begin to try and nail down any areas where the
threat is greater.

The front is expected to stall south of the forecast area late
Wednesday into Thursday which should keep rain chances fairly
minimum and limited to just the far southern counties.

Friday Through Sunday.

Hot and humid conditions expected Friday into the weekend with the
ridge beginning to build back in again. Temperatures aloft will be
cool enough to allow for diurnal convective initiation which
combined with the very weak to near zero flow aloft to create
additional risks for isolated flooding. A lack of forcing will limit
the coverage and longevity of any convection that forms but with
little to no flow, any storm that forms will have little motion.
Peak heat index values are likely to return into the upper 90s to
low 100s by Sunday.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 101 PM EDT Sun Aug 10 2025

Impacts:

- Fog possible again predawn Monday, especially at KBMG

Discussion:

VFR conditions are expected for the period at most sites.

Scattered to briefly broken cumulus will continue this afternoon,
diminishing early this evening. More cumulus will pop up on Monday.
Otherwise, some cirrus and perhaps some mid clouds will move through
at times.

Ground fog is possible at all but IND overnight, but believe that
KBMG has the best odds. Will continue to mention a period of fog
there overnight.


&&

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

$$

SHORT TERM...50
LONG TERM...White
AVIATION...50