Severe Thunderstorm Warning 224, NWS Indianapolis, IN

Area Forecast Discussion
National Weather Service Indianapolis IN
535 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

&&

.MESOSCALE UPDATE...
Issued at 534 PM EDT Sun Jun 21 2026

An MCV currently located across central IL is pushing eastward
towards the region. Dewpoints continue to rise ahead of the
approaching disturbance amid increasing moisture advection. Latest
surface observations depict dewpoints well in the 60s to near 70F.
Dewpoints along or near the I-70 corridor are now in the low to mid
60s. This along with daytime heating has allowed for sufficient
destabilization over the past few hours. Meanwhile, strengthening
deep-layer flow is promoting effective shear around 35-50kt
supporting supercell potential.

Multiple tornadoes have already been reported across central
Illinois recently with the modestly buoyant and highly sheared
environment likely to push into southwest portions of central IN
over the next hour and eventually further northeast. Latest IND VAD
wind profiles already support this with an enlarging hodograph and
significant low-level veering. Any discrete cells that form ahead of
the developing linear storm mode across central Illinois will pose
the greatest tornado threat, but line embedded tornadoes are also
possible given ample low-level wind shear. Isolated large hail
cannot be ruled out with any discrete cells. However, modest
instability and potential for upscale growth in a moisture rich
environment limits this threat.

Radar imagery has shown one long-lived discrete supercell out ahead
of the developing linear segments in central Illinois. If this
supercell can continue to remain deviant it will likely impact far
western portions of of the forecast area including Sullivan and Vigo
counties within 20-25 minutes. The environment upstream of this
storm remains favorable for supercell maintenance and tornado
potential.

&&

.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 (18Z TAF Issuance)...
Issued at 140 PM EDT Sun Jun 21 2026

Impacts:

- Scattered to numerous TSRA around 21Z-06Z...sct convection after
- Outside of convection...CIGs to deteriorate from west to east, to
  MVFR 23Z-02Z...and to IFR, NW to SE, during 03Z-08Z
- Winds veering to southerly by 04Z south of KLAF...and NNW by 18Z
  Monday

Discussion:

VFR conditions will continue near central Indiana terminals through
22Z at KLAF...and 23Z-02Z along/south of I-70.  Surface low
pressure, currently over northern Missouri, will slowly cross the
region through the TAF period.  Mid/high clouds will gradually give
way to lower CIGs around 050-060 by 20Z-21Z.  Associated area of
convection currently over most of Illinois will reach KLAF/KHUF
around 21Z...and KIND/KBMG by 23Z...continuing into the late
evening.  Expect further scattered -SHRA/convection through at least
12Z Monday.

Winds to gust to 15-20KT at times through the period outside of
convection...with flow veering with the passing surface low, from
southeasterly this afternoon and early evening, to southerly by 04Z
at sites south of KLAF.

&&

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

&&

MESOSCALE...Melo
AVIATION...AGM
DISCUSSION...AGM/Melo

Hazardous Weather Outlook
National Weather Service Indianapolis IN
436 PM EDT Sun Jun 21 2026

INZ021-028>031-035>049-051>057-060>064-067>072-222045-
Carroll-Warren-Tippecanoe-Clinton-Howard-Fountain-Montgomery-Boone-
Tipton-Hamilton-Madison-Delaware-Randolph-Vermillion-Parke-Putnam-
Hendricks-Marion-Hancock-Henry-Vigo-Clay-Owen-Morgan-Johnson-Shelby-
Rush-Sullivan-Greene-Monroe-Brown-Bartholomew-Knox-Daviess-Martin-
Lawrence-Jackson-Jennings-
436 PM EDT Sun Jun 21 2026

This hazardous weather outlook is for central Indiana.

.DAY ONE...Tonight.

Thunderstorms are expected this afternoon into tonight with some
severe storms possible, mainly from through 100 AM EDT. Damaging
winds and isolated tornadoes are the primary threats from the storms.

Lightning is also a threat with any thunderstorm.

In addition, moderate to heavy rainfall is expected this afternoon
into tonight which may lead to localized flooding and increase
current minor river flooding.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Additional thunderstorms are possible Monday and again Wednesday
through Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to pass along flooding and severe weather
reports.

&&

More information, along with other weather, hydrological and climate
information can be found at http://weather.gov/ind

INZ065-222045-
Decatur-
436 PM EDT Sun Jun 21 2026

This hazardous weather outlook is for central Indiana.

.DAY ONE...Tonight.

Residents living southwest of McCoy Lake are encouraged to closely
monitor conditions through tonight as releases from the dam are
planned.

Thunderstorms are expected this afternoon into tonight with some
severe storms possible, mainly from through 100 AM EDT. Damaging
winds and isolated tornadoes are the primary threats from the storms.

Lightning is also a threat with any thunderstorm.

In addition, moderate to heavy rainfall is expected this afternoon
into tonight which may lead to localized flooding and increase
current minor river flooding.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Additional thunderstorms are possible Monday and again Wednesday
through Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to pass along flooding and severe weather
reports.

&&

More information, along with other weather, hydrological and climate
information can be found at http://weather.gov/ind