381
FXUS63 KIND 081358
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
958 AM EDT Sat Aug 8 2026

.KEY MESSAGES...

- Hot and humid through at least mid week

- Near daily chances for showers and storms

- At least an isolated severe threat at times late Sunday into late
  Wednesday, with damaging winds and localized flooding the primary
  threats

&&

.FORECAST UPDATE...
Issued at 958 AM EDT Sat Aug 8 2026

Forecast is in good shape this morning. Mainly minor tweaks were
made based on latest observational trends.

Areas of stratus developed early this morning across mainly the
northern half of central Indiana, and these are moving east. Upped
sky cover where needed based on satellite imagery. Satellite also
shows some elevated smoke.

Hot and humid conditions will persist as a weakening cold front
sinks into the area. Dewpoints will be in the 70s. While the front
will have the moisture to work with, forcing will be weak. Will keep
the mainly slight chance PoPs.

Nudged highs up a bit based on temperature trends and latest
guidance.

&&

.DISCUSSION (Today through Friday)...
Issued at 313 AM EDT Sat Aug 8 2026

TODAY AND TONIGHT

A remnant outflow boundary from yesterday that triggered widely
scattered convection through the early overnight continues to linger
across the region, though it has washed out somewhat. A subtle
shortwave disturbance aloft will slowly pass through the region
today, and this may combine with the presently warm and very humid
airmass to produce additional isolated to widely scattered
convection, mainly this afternoon into early evening, before
subsidence behind the weak wave and slightly drier air moving into
the area with surface high pressure combine to bring at least a
brief end to rain chances.

A cap of varying strengths is noted in forecast soundings centered
around 850 mb, and this along with relatively weak shear will be the
primary limiting factor on storms today. An isolated weak downburst
or small hail will certainly be possible in any storms that can
sustain themselves, but the primary concern will be heavy downpours
and localized flooding, particularly in areas that have received
significant rainfall in the past several days.

Highs today should be at or just below persistence today, in the mid
to upper 80s, with a 90 degree reading not out of the question
south. The slightly drier air will allow lows tonight to drop down
into the 60s across the area.

Surface high pressure will produce light to calm winds tonight, and
expect areas of fog, perhaps dense in spots, to form late in the
evening into the overnight hours.

SUNDAY ONWARD

Broadly speaking, warm and humid conditions will continue through
mid week, with some moderation in daytime highs late in the week, as
a broad upper level ridge persists from the southeastern into the
western CONUS. The hottest conditions will be early in the week,
with highs Sunday through at least Tuesday well into the 80s or low
90s across central Indiana, and heat index values possibly peaking
in the mid 90s to low 100s each day, though convection potential
increases the uncertainty with respect to this. While we appear
unlikely to reach strict heat advisory criteria at any point, at
least moderate heat risk is likely through mid week, and major heat
risk is likely to nudge into the area on one or more days, though
again, convection significantly complicates predictability of this.

Thunderstorms will be a threat for at least portions of the area
each day, though PoPs will be highest Tuesday into Thursday, when a
weak surface front and more substantial upper level disturbances on
the periphery of the ridge come into play.

There will be at least a low threat for severe storms each day from
Sunday through Wednesday, with significant uncertainty with respect
to exact areas and timing owing to the inherent low predictability
of weakly forced warm season convection, which is largely
thermodynamically/cold pool driven. In any case, damaging winds will
be the primary severe threat, with of course a continued concern for
heavy downpours and localized flooding as highly efficient rain
rates will remain a concern with seasonably high freezing levels and
precipitable water values at or at times well above normal, and some
areas seeing substantial rain in recent days.

Though chances for showers and storms will persist beyond mid week
into the latter portion of the week, a more moderate airmass will
cut down on available instability and result in more limited severe
threat beyond mid week. Run to run model consistency in recent days
has been somewhat poor, though, so stay tuned in this regard.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 739 AM EDT Sat Aug 8 2026

Impacts:

- Patchy fog this morning and again tonight.

- Low chance for showers/storms

Discussion:

Warm and humid conditions prevail with patchy fog reported across
the region. Fog has been hit or miss at any given location, with a
few terminals reporting no fog at all and others seeing visibility
under 1 mile. Fog is expected to dissipate quickly after sunrise
this morning. Similar conditions are expected tonight with humid air
and light winds. As such, renewed fog development is possible again
overnight.

Light winds out of the southwest should become westerly today while
gradually increasing. Winds around 10kt are possible near IND with
gusts up to 20kt this afternoon. Lighter winds are expected
elsewhere with a few gusts around or just above 15kt. Calm to light
and variable conditions return tonight.

Additionally, there is a low chance of showers and thunderstorms
today. Most guidance shows storm activity just very few and far
between. Probabilities at any given location is around 15 to 20
percent. We will not include rain or thunder as a prevailing group
in the TAFs for now, but a tempo group may be needed later if trends
point towards a specific area for likely development.


&&

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

$$

UPDATE...50
AVIATION...Eckhoff
DISCUSSION...Nield