Severe Thunderstorm Warning 181, NWS Indianapolis, IN

Area Forecast Discussion
National Weather Service Indianapolis IN
906 PM EDT Sat Aug 16 2025

.KEY MESSAGES...

- Rain likely tonight as a decaying storm complex moves southward

- Hot and humid conditions continue through Tuesday, cooler
  afterwards

- Additional showers and storms likely during a frontal passage
  Tuesday into Wednesday

&&

.FORECAST UPDATE...
Issued at 906 PM EDT Sat Aug 16 2025

Surface analysis this evening shows strong high pressure in place
over the northern plains, influencing the weather east into the
Great Lakes and Indiana. Aloft, a short wave was pushing across WI
and MI, helping to trigger storms. Meanwhile at the surface a very
warm and humid air mass remained in place across Central Indiana.
These features along with diurnal heating has resulted in
thunderstorm development, mainly within the Wabash Valley.

All afternoon and evening storms that have developed have shown
short lived sustainability as cold pools quickly become
dominate...choking updrafts and leading to an eventual dissipation
of the storm.

Earlier HRRR run suggesting an overnight MCS as backed off that
solution and given the convection across northern Indiana and NW
Indiana diurnal instability across those locations will be
considerably less. Thus continued convection, slowly diminishing, is
expected for the next 1-3 hours downstream of the current storms. In
the meantime storms may be capable of gusty winds due to a
downdraft, but widespread severe weather is not expected. Will use
high pops for the next few hours, trending toward low chc pops
overnight to account for the stray, renegade shower or storms due to
the very warm and moist airmass.

As dew point depressions once again fall to 1-3F, patchy fog,
particularly in rural areas will be possible.

Look for overnight low temperatures in the upper 60s and lower 70s.

&&

.MESOSCALE UPDATE...
Issued at 235 PM EDT Sat Aug 16 2025

As of early this afternoon, convection has generally remained
limited to the outflow boundary from the decayed convection that
moved through the northeastern portions of the forecast area.
Recently a Severe Thunderstorm Warning was issued for a storm to the
east of Indianapolis as it briefly showed the potential for both
severe hail and winds with good mid-level convergence. The eastern
areas of the forecast area continue to be the focus point for
thunderstorms over the next two hours, but expect focus then to
shift westward later into the early evening.

The best shear and ML CAPE continues to be across the western and
northwestern counties, but without a boundary to initiate, expect
fairly minimal coverage over the next few hours. Towards the early
evening, the cu field should fill in with at least a few showers and
storms popping up in the aforementioned area once the cap fully
erodes.

Greatest threats continue to be will be marginally severe winds and
torrential downpours along with hail in the strongest storms of the
day.

&&

.SHORT TERM (This evening through Sunday)...
Issued at 235 PM EDT Sat Aug 16 2025

Rest of Today and Tonight.

For the latest on the ongoing convection and thoughts through the
evening, see the mesoscale discussion above.

As the diurnally driven convection gradually comes to an end this
evening, focus shifts to tracking a likely MCS across Wisconsin with
good model agreement in a southerly progression through the
overnight hours. There are some differences in the timing and
strength of this gradually decaying MCS, but the WRF-ARW which
typically handles organized convection better brings in the storms
towards 6-9Z which lines up well with the NAM and is a bit faster
than the HRRR.

This MCS should have a well-defined cold pool which will allow it to
progress into Indiana while maintaining at least some threat for
damaging winds with 1000-1500 J/kg of CAPE. The lack of shear will
be made up by the strength of the cold pool but do expect a general
downward trend as it moves southward. Overnight lows will remain
mild again tonight with most spots generally falling into the low
70s.

Sunday.

Generally warm and dry conditions are expected for Sunday with some
delay in the better heating as cloud cover from the dissipated MCS
takes time to clear. This MCS should progress south of the forecast
area but if it stalls and completely dissipates there could be an
initiation point along the outflow boundary and associated
differential heating boundary. Otherwise, chances for convection
look low with only an isolated shower or storm possible during the
afternoon and evening during peak heating. As a result of the
morning clouds, daytime highs are trending lower for Sunday with
increasing confidence that highs remain sub-90 with some spots
potentially struggling to rise out of the mid 80s depending on the
thickness and longevity of the cloud cover.

&&

.LONG TERM (Sunday night through Saturday)...
Issued at 235 PM EDT Sat Aug 16 2025

Sunday Night Through Tuesday.

Quiet weather is expected to continue into Sunday night with broad
ridging continuing to dominate the weather pattern. There will be
slight northerly component to the surface winds which will allow for
some drier air to slowly work into the area, but still expect to see
dew points in the upper 60s to low 70s towards daybreak. Stronger
southerly flow returns Monday into Tuesday ahead of a frontal
passage Tuesday night into early Wednesday.

Models are all over the place on the timing of the front and the
associated weather with the passage, but generally expect to see
showers and thunderstorms ahead of the front with a low-end
potential for more organized and strong to severe convection. With
weak shear and only modest instability, organized convection
potential looks low but will need to be monitored in the days ahead.

Wednesday Through Saturday.

Cooler weather is expected in the aftermath of the frontal passage
with daytime highs in the low 80s and overnight lows in the low to
mid 60s through the remainder of the workweek. Dry air both near the
surface and aloft should keep any precipitation chances minimal, but
there does look to be a more organized and stronger upper level low
across southern Canada Saturday into Sunday which could bring
additional showers and storms for the second half of the weekend
into next week. Looking beyond into the following workweek,
conditions look to favor cooler than normal weather to finish the
month.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 644 PM EDT Sat Aug 16 2025

Impacts:

- Diurnal TSRA ending this evening.

- More TSRA possible at LAF/IND 08Z-11Z

- Fog possible at BMG/HUF tonight.

Discussion:

Low confidence continues in TAFs given uncertainties in further
convective development tonight and Sunday. Radar trends show a few
diurnal driven storms over west Central Indiana and of far southern
Central Indiana, driving S or SE. Outflow boundaries were visible on
Radar from these storms, as the cold pool was cutting off updrafts
and limiting further updrafts. Have used VCTS for the next few hours
as diurnal convection is expected to wane in the next few hours.

HRRR suggests overnight convective complex devlopment NW of Indiana
with eventual propagation to northern and east Central Indiana. Low
confidence is present at this time for the devlopment of this
feature. For now a VCTS mention has been included at LAF and IND.

Light winds and high dew points across the area may also lead to Fog
development and MVFR visibilities at HUF and BMG.

Otherwise VFR conditions are expected outside of any convection.

&&

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

UPDATE...Puma
SHORT TERM...White
LONG TERM...White
AVIATION...Puma

Hazardous Weather Outlook
National Weather Service Indianapolis IN
244 PM EDT Sat Aug 16 2025

INZ021-028>031-035>049-051>057-060>065-067>072-171845-
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-Decatur-Knox-Daviess-
Martin-Lawrence-Jackson-Jennings-
244 PM EDT Sat Aug 16 2025

This hazardous weather outlook is for central Indiana.

.DAY ONE...Through Tonight.

Isolated showers and storms this evening with additional more
widespread storms tonight. Damaging winds are the primary threat.

Outside of storms, heat indices around 100 will continue through the
evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Isolated to scattered thunderstorms are expected again Sunday across
central Indiana. A few storms may be strong to severe on Sunday with
strong winds and locally heavy rain. More widespread showers and
storms are possible Tuesday and Wednesday next week.

Outside of storms, high temperatures near 90 and humid conditions
will result in afternoon heat indices at or above 100.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

&&

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

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Special Weather Statement
National Weather Service Indianapolis IN
923 PM EDT Sat Aug 16 2025

INZ021-029-030-036-037-170200-
Clinton IN-Montgomery IN-Boone IN-Tippecanoe IN-Carroll IN-
923 PM EDT Sat Aug 16 2025

...A strong thunderstorm will impact portions of southeastern
Carroll, southeastern Tippecanoe, Clinton, northern Boone and
northeastern Montgomery Counties through 1000 PM EDT...

At 922 PM EDT, Doppler radar was tracking a strong thunderstorm near
Lafayette, moving south at 35 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Lafayette, Frankfort, West Lafayette, Rossville, Thorntown, Dayton,
Mulberry, Darlington, Kirklin, Colfax, Clarks Hill, and Michigantown.

This includes Interstate 65 between mile markers 145 and 174.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4022 8624 4017 8624 4004 8675 4042 8694
      4052 8647
TIME...MOT...LOC 0122Z 343DEG 29KT 4040 8675

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

White

Special Weather Statement
National Weather Service Indianapolis IN
926 PM EDT Sat Aug 16 2025

INZ039-040-170200-
Madison IN-Hamilton IN-
926 PM EDT Sat Aug 16 2025

...A strong thunderstorm will impact portions of southwestern Madison
and Hamilton Counties through 1000 PM EDT...

At 926 PM EDT, Doppler radar was tracking a strong thunderstorm 7
miles northwest of Noblesville, or 21 miles north of Indianapolis,
moving southeast at 30 mph.

HAZARD...Wind gusts of 50 to 55 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Carmel, Fishers, Noblesville, Westfield, Cicero, Sheridan, Lapel,
Arcadia, Atlanta, and Morse Reservoir.

This includes Interstate 69 between mile markers 203 and 211.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4007 8574 3993 8602 3993 8613 4002 8624
      4012 8624 4022 8613 4022 8603
TIME...MOT...LOC 0126Z 310DEG 28KT 4009 8615

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

White

Special Weather Statement
National Weather Service Indianapolis IN
928 PM EDT Sat Aug 16 2025

INZ038>041-170200-
Tipton IN-Madison IN-Delaware IN-Hamilton IN-
928 PM EDT Sat Aug 16 2025

...A strong thunderstorm will impact portions of Madison, Delaware,
northeastern Hamilton and southeastern Tipton Counties through 1000
PM EDT...

At 928 PM EDT, Doppler radar was tracking a strong thunderstorm over
Alexandria, or 9 miles south of Fairmount, moving southeast at 35
mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Muncie, Anderson, Elwood, Alexandria, Yorktown, Chesterfield,
Edgewood, Frankton, Eaton, Daleville, Summitville, Gaston, Selma,
Orestes, Woodlawn Heights, Country Club Heights, River Forest, and
Ball State University.

This includes Interstate 69 between mile markers 234 and 251.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4007 8574 4022 8601 4025 8595 4034 8590
      4038 8578 4038 8537 4037 8533 4021 8522
TIME...MOT...LOC 0128Z 308DEG 29KT 4028 8563

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Puma