533
FXUS63 KIND 270221
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1021 PM EDT Sun Jul 26 2026

.KEY MESSAGES...

- Hot and humid conditions through Monday

- One or more thunderstorm complexes possible tonight into Monday
  night, with damaging winds and heavy rainfall the primary
  threats, though uncertainty on exact details remains high

- Temperatures nearer normal and less humid mid week

&&

.FORECAST UPDATE...
Issued at 1020 PM EDT Sun Jul 26 2026

Latest update has overall dropped convective chances through the
overnight with both limited storm initiation so far over Upper
Midwest and reflection thereof in latest CAMs....with a better
opportunity for at least 1-2 storm complexes from midday Monday
and especially later on into Monday night. Near term threat will
maintain couple showers and non-severe TRWs along a NNW-SSE axis
from near Sullivan down to Washington and west through 04Z which
may include an isolated 40-50 mph gust per highest towers up to
20-25 kft. Stray convection may linger over these far-west/
southwest zones into the overnight where 3000+ J/kg MUCAPE will
nudge eastward from Illinois. Despite light winds, dewpoints in
generally the low to mid-70s will guide overnight
temperatures...with lows by early Monday ranging from 68 in
Winchester to 74 in Vincennes.

&&

.DISCUSSION (This evening through Sunday)...
Issued at 340 PM EDT Sun Jul 26 2026

This Afternoon into Monday Night...

A highly uncertain forecast scenario remains the case again today,
particularly with respect to the severe thunderstorm threat from
late today into Monday night, with multiple scenarios on the table.
As is often the case with these depth of the warm season setups, the
exact evolution of each convective round will be largely
thermodynamically driven and heavily influenced by the prior rounds,
resulting in low confidence in the exact details as time goes on.

A volatile airmass is in place this afternoon to our southwest
across the mid Mississippi and far lower Ohio Valleys, along and
west of a frontal zone, characterized by temperatures in the mid 80s
to mid 90s and dewpoints as high as the low 80s, resulting in MLCAPE
values near 5000 J/kg, along with modest to strong effective shear
values of 25-40KT overlapping. This should promote thunderstorm
development late this afternoon into this evening as a subtle upper
level disturbance slides southeast along the periphery of the upper
level ridge, and this activity may nudge into the southwestern
portions of the forecast area this evening. Will stick with chance
PoPs for now, as it is unclear how far east this activity will make
it, as the instability gradient will likely result in storm motion
with a largely southerly component, and substantial convective
inhibition remains across central Indiana on the milder side of the
cloud-reinforced differential heating frontal boundary.

Additional severe convection is likely to develop over the upper
Midwest, and this activity could make it into central Indiana as
early as the pre-dawn hours Monday, though the unfavorable diurnal
timing may limit the severe threat should this come to pass. With
both of these possible rounds of thunderstorms, damaging winds would
be the primary concern.
Trimmed high temperatures back a couple/few degrees with low clouds
and fog impacting morning insolation. Clouds are beginning to
scatter out however, so do not expect nearly as strong an impact to
high temperatures as what occurred yesterday, with the mid to upper
80s still well in reach today, and perhaps even a 90 degree reading
sneaking into our far southwest.

Partly cloudy skies can be expected this afternoon with warm and
humid conditions driving heat index values into the 90s across
portions of the area.Another round of convection appears likely
to initiate somewhere over the upper Great Lakes tomorrow
afternoon associated with an upper level shortwave and surface
cold front, again likely dropping southerly along an instability
gradient in a continued volatile airmass characterized by ample
shear and instability, along with precipitable water values at
times in the vicinity of 2 inches. This will present again a
primarily damaging wind threat, though an isolated tornado cannot
be ruled out. Additionally, the aforementioned moist airmass along
with deep warm rain processes as the wet bulb zero height remains
seasonably high will present a heavy rainfall and localized flash
flood threat, limited by the relatively progressive nature of any
thunderstorm complexes - but a fairly strong westerly low level
jet ahead of the cold front could produce some
regeneration/training potential on the western flank of any MCS
depending upon cold pool orientation.

Temperatures will have the potential to soar well into the 80s or
low 90s on Monday afternoon, though this, too, is uncertain as any
early day convective debris cloudiness could limit the impact of
warm advection and insolation - the more sun, the greater the
potential for highs getting to the 90 degree mark, which may couple
with dewpoints well into the 70s to produce heat index values at or
above 100 degrees Monday afternoon.

Tuesday onward...

Cold frontal passage Monday night into early Tuesday will bring
temperatures back down much closer to seasonal normals from mid week
onward, with a largely dry forecast until very late in the week as
surface high pressure dominates the area. As the ridge aloft
retrogrades slightly and the overall pattern amplifies, upper level
disturbances late in the week may promote rain chances, though
significant disagreement on these systems precludes more than a
slight chance to low chance PoP in any one period from Friday into
the weekend.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 646 PM EDT Sun Jul 26 2026

Impacts:

- Lingering MVFR ceilings at KBMG and KHUF possible this evening

- MVFR fog possible overnight

- Thunderstorms may impact KHUF for a short time late this evening

- Storm complexes may impact the area mid morning through mid
  afternoon and again Monday evening into the overnight

Discussion:

Lower clouds have been stubborn to mix out at both KBMG and KHUF but
should see ceilings rise to VFR over the next few hours. Convection
has fired quickly early this evening from south central Illinois
southeast into western Kentucky along the instability gradient. This
may drift east a bit this evening and potentially could see
convection approach KHUF for a short time.

There remains a highly conditional thunderstorm threat late tonight
and especially Monday morning as a storm complex over the upper
Midwest dives into the region. Will maintain a PROB30 at all sites
over a 6 hour window through early afternoon with confidence still
too low to justify a more specific risk. Additional convection may
impact the terminals through the rest of the day with the
possibility for another complex Monday evening and night. Any storms
that do impact the area will have the potential to be intense.

With plentiful low level moisture and light to calm winds tonight
expect fog development again...though not quite to the same degree
as this morning as mid and high clouds will work against radiational
cooling. Will take the outlying sites down to 3-4SM. Winds will be
fairly light and frequently variable through the period.

&&

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

&&

$$

UPDATE...AGM
AVIATION...Ryan
DISCUSSION...Nield