325
FXUS63 KIND 261920
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
320 PM EDT Fri Jun 26 2026

.KEY MESSAGES...

- Flood Watch from through Saturday afternoon for southern portions
  of central Indiana with 1 to 3 inches of rain possible

- Multiple rounds of showers and storms producing torrential
  rainfall and localized flooding expected through Saturday night

- Isolated severe storms possible across south central Indiana this
  afternoon and evening

- Hot and humid conditions expected for much of next week with
  multiple days in the 90s and heat indices over 100 degrees

&&

.DISCUSSION (This evening through Friday)...
Issued at 319 PM EDT Fri Jun 26 2026

Today through Saturday Night

Quasi-zonal flow aloft above an east-west oriented baroclinic zone
will allow a mid-level wave to progress into Indiana this evening.
Surface low pressure associated with the wave will allow the
baroclinic zone to lift northward as a warm front this afternoon.
Numerous showers have developed today, initially from broad
isentropic lift but some convective elements have also developed
this afternoon. Low-level instability increases with time as the
warm and buoyant air mass behind the front advects northward.

Though instability never becomes abundant, it likely becomes at
least sufficient for continued scattered convective development into
tonight. As the low approaches, model hodographs show some
elongation and curvature in the 1-2km layer due to a strengthening
low-level jet. Given a temperature profile that shows roughly moist
adiabatic lapse rates, relatively shallow convection with minimal
lightning is possible today. Despite this, some of these
showers/storms may exhibit mesocyclone development due to the low-
level shear profile. As such, isolated tornadoes are possible later
today into tonight mainly across our southwest where better surface
lapse rates are found. Strong wind gusts are also possible if
activity can congeal into a line or cluster.

Our primary threat, however, is flooding and heavy rainfall. With
deep moisture, moist adiabatic lapse rates, and a deep warm cloud
layer, we can expect efficient rainfall processes today.
Additionally, hodographs indicate that mature convection could
become slow to stationary at times. Very heavy rainfall rates with
prolonged duration across already moist ground may lead to a
flooding and flash flooding threat through tonight. Additional
showers and thunderstorms are possible on Saturday as the low
pressure itself sits overhead, though activity will be more isolated
in nature. The Flood Watch will be extended until 18z Saturday to
account for this.

Convective coverage is a bit uncertain through tonight due to the
relatively weak surface forcing as well as a mid-level wave that is
weaker on recent model runs compared to earlier ones. Convective-
allowing models have a difficult time with storm placement in such
situation, and run to run consistency is likely to be quite low.

Sunday into Next Week

A few storms may linger into Sunday morning but the trend will be
for the frontal boundary to lift north of the area Sunday as deep
ridging expands into the Ohio Valley. This will serve as the
transition point towards progressively hotter and more humid
conditions that will last through much of next week as the core of
the ridge peaks with heights at 596-597dam. Multiple days with highs
in the 90s are anticipated with the highest heat indices of the
summer so far rising into the 100s during the afternoons. Isolated
late afternoon and evening convection may develop by late next week
as the mid-level heights begin to fall back. As the upper ridge
retrogrades to the southwest next weekend...will need to monitor for
an increased risk for convective clusters riding along the periphery
of the ridge impacting parts of the region.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 136 PM EDT Fri Jun 26 2026

Impacts:

- Numerous showers throughout the day and tonight with thunder
  possible as well this afternoon and early evening

- IFR conditions expected through tonight and into Saturday

Discussion:

Surface low pressure west of Indiana has lead to scattered showers
and a few thunderstorms today. Showers and thunderstorms are
expected to continue on and off this afternoon and into tonight.
Periodic reductions in visibility are likely within heavier showers
or storms. Rain chances diminish on Saturday but isolated showers
are still expected to persist across central Indiana.

Ceilings have lowered into IFR territory for most of the region,
with only LAF remaining in VFR. That is expected to change as the
atmosphere continues to moisten. IFR conditions are expected to
continue into the day on Saturday with periodic fluctuations into
MVFR possible.

Winds will be primarily out of the southeast today ahead of the low.
A period of light and variable winds is possible as the low pressure
center arrives tonight. Winds may become southwesterly on its
southern flank with the exact track deciding which terminals see a
shift to southwesterly winds. Speeds look to remain under 10kt for
the most part.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Saturday morning for INZ051>053-060>065-
067>072.

&&

$$

AVIATION...Eckhoff
DISCUSSION...Ryan/Eckhoff