083
FXUS63 KIND 220009
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
809 PM EDT Sun Jun 21 2026

.KEY MESSAGES...

- Heavy rain and severe storms are possible this afternoon into
  early Monday

- Flooding threat for both river/non-river will increase through the
  early week from heavy rainfall on damp/saturated soils

- Temperatures will trend from slightly below normal to near normal
  through Saturday...trend to very warm/humid late in period

&&

.DISCUSSION (This evening through Sunday)...
Issued at 302 PM EDT Sun Jun 21 2026

This afternoon through Monday...

Quiet weather conditions continue across central Indiana at this
time ahead of an approaching MCS with an associated MCV. Look for
this system to continue pushing eastward supporting widespread
showers and thunderstorms towards this evening. Increasing clouds
has limited destabilization to some degree, but moisture advection
and daytime heating is allowing for gradual destabilization this
afternoon. Deep-layer and low-level shear will also increase over
the next several hours with the approaching disturbance promoting
stronger flow. Favorable effective shear values around 30-50 kt
combined with modest instability supports the potential for
organized storms with all hazards possible.

Latest model guidance still depicts enlarging low-level hodographs
across portions of central IN favoring an isolated tornado threat.
The greatest tornado threat is across southwest portions of central
Indiana where the greatest instability and low-level wind shear
overlap. Some uncertainty remains on storm mode at least initially.
There does appear to be at least a brief opportunity for discrete
cells later this afternoon into the early evening before multiple
linear segments then develop leading to a greater damaging wind gust
threat with embedded tornadoes possible. Isolated large hail cannot
be ruled out, but modest instability and linear storm mode by the
evening hours should mostly limit this threat.

A Flood Watch is in effect through 8 AM Monday morning for much of
central IN with the potential for 1 to 3 inches of rainfall from
multiple rounds of storms. Locally higher amounts cannot be ruled
out. Expect precipitation chances to diminish late tonight into
Monday morning as the aforementioned disturbance shifts east.
Surface high pressure will then build in providing quiet weather for
much of the day Monday. Isolated showers are possible across east-
central IN through the first half of the day. Lingering clouds and
northerly surface flow will keep temperatures cooler. Look for highs
in the 70s.

Monday night through Sunday...

Generally active pattern will continue this week amid overall zonal
pattern.  Established trough over northern North America that has
been guiding mid-latitude pattern...will shift from south-central
Canada to more pronounced, perhaps cut-off upper lows over SW Canada
to the northern Rockies late this week.  This transition will allow
a subtropical ridge to build over the central US, bringing
seasonably warm and humid conditions into Indiana next weekend.

The next round of broad and seasonably weak Canadian surface high
pressure will pass through Indiana Monday night to Tuesday night,
dropping dewpoints to the mainly low to mid-50s at night, and light
northerly breezes under H850 temperatures as low as 10 degrees
Celsius during the day Tuesday.  Transition back to more summery
weather Wednesday with light southwest flow returning moderate
humidity ahead of next wave...which should bring periods of
scattered RWs/few TRWs through the Wednesday night-Thursday night
period as the disturbance`s boundary slowly crosses the region.

Expect a shorter period of improvement around the Friday timeframe
as western trough deepens near Vancouver...only allowing next
northern surface ridge to graze the CWA, with isolated diurnal
convective chances continuing...and increasing through Saturday as
light southerly flow boosts humidity through moderate to high levels.
Temperatures through the workweek to see subtle increase in
afternoon maximums from around 80F to low 80s, although mid-80s
should be more common along the US-50 corridor...while morning lows
steadily climb from 50s to 65-70F by week`s end.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 809 PM EDT Sun Jun 21 2026

Impacts:

- Thunderstorms ongoing at the beginning of the TAF period with
lowered ceilings and visibilities
- Rain and isolated thunderstorms to continue through around 12Z
- MVFR to IFR ceilings to persist from early morning through much of
tomorrow
- Winds shifting from SE to W to N through the period

Discussion:

Ongoing thunderstorms at the start of the period with strongest
storms just exiting TAF sites as of 00-01Z. As these storms move off
to the east, expect visibilities to improve but MVFR to IFR ceilings
are expected to persist through much of the day tomorrow.

Winds will start out from the SE with gusts up to 20 kts outside of
thunderstorm wind gusts. Winds will shift to out of the SW by early
morning and eventually from the north as this storm system moves
through the region.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 8 AM EDT Monday for INZ028>030-035>037-039-
043>048-051>057-060>065-067>072.

&&

$$

AVIATION...KF
DISCUSSION...AGM/Melo