Flash Flood Warning 24, NWS Indianapolis, IN

Area Forecast Discussion
National Weather Service Indianapolis IN
116 PM EDT Sat Jun 27 2026

.KEY MESSAGES...

- Flood Watch continues through early this afternoon for far
  southern portions of central Indiana

- Thunderstorms producing heavy rainfall and localized flooding will
  focus across southern Indiana early this morning

- Scattered thunderstorms will impact much of the area this
  afternoon and evening with the potential for a few storms to produce
  damaging winds across the southwest half of central Indiana

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

&&

.FORECAST UPDATE...
Issued at 831 AM EDT Sat Jun 27 2026

Areas of fog developed across central Indiana this morning, with
some locally dense fog included. Added fog to the forecast for the
next few hours. Surface observations are already showing some
improvement.

The axis of heavy rain and thunderstorms remains just south of the
forecast area this morning. Still, models generate some additional
convection across the south later this morning/early this afternoon,
which makes sense with the front still in the area. Will keep Flood
Watch as is. If it looks like more convection may develop later in
the afternoon, may have to extend the time of it again.

Additional light showers have developed farther to the north, so
have adjusted PoPs as needed. CAMs generate additional convection
near the I-70 corridor into this evening, so will keep PoPs going
into the evening at least that far north.

&&

.DISCUSSION (Today through Friday)...
Issued at 249 AM EDT Sat Jun 27 2026

A muggy...stagnant airmass has settled across the forecast area
early this morning as low pressure drifts through the Ohio Valley.
Convection continues to grow in coverage across southern Indiana
along the remnant frontal boundary with an axis of training cells
impacting far southwest portions of the forecast area. 06Z
temperatures were generally in the upper 60s and lower 70s.

The front will remain nearly stationary over the Ohio Valley today
then will lift north across the area Sunday in response to expanding
upper level ridging over the Mississippi Valley. The deep ridging
will take root over the region by early next week resulting in an
extended period of hot and humid weather likely resulting in the
hottest days of the summer to date.

Today and Tonight

The low level jet has gradually strengthened over the last few hours
in the vicinity of the Ohio River and its orientation to the W/SW
with broad isentropic lift present as well provides and environment
highly supportive of training convection across southern Indiana and
western Kentucky in the near term. PWATs over the lower Wabash
Valley have been hovering near 2.2 inches allowing for highly
efficient rainfall rates within the axis of slow moving convection.

The immediate focus through daybreak will be across far southern
portions of the forecast area as the convection drifts east. Flash
flooding is possible with an additional 1 to 3 inches over the next
few hours. To this point...the axis of heaviest rainfall has aligned
just south of the forecast area and as it stands right now...
flooding concerns will likely be greatest in the zone from Gibson
and Pike Counties east through Washington County. The Flood Watch
will remain in effect across far southern portions of central
Indiana through 18Z.

The convective focus is likely to shift closer to the Ohio River
after daybreak as the boundary drifts in that direction and a subtle
weakening of the low level jet occurs. But as the day progresses...
some breaks in the lower stratus will occur with better heating
supporting a more unstable airmass by this afternoon and evening.
With deep moisture lingering over the region and the presence of
another subtle shortwave pivoting through the area...scattered
convection will develop and expand northeast across the forecast
area by late day. The potential remains for a few of the stronger
cells to carry a localized damaging wind risk focused especially
across the southwest half of the forecast area. But again...the main
concern will be locally heavy rainfall from slow moving convection
with the lower Wabash Valley at greatest risk due to the several
inches of rain that has already fallen over the last 36 hours or so.

Convection will gradually diminish in coverage late this evening
although may see additional storms slip back into the southwest
half  of the forecast area in the predawn hours Sunday as a final
wave drifts down the eastern flank of the approaching upper level
ridge.

Sunday Through Next Week

A few storms may linger Sunday morning but a drier trend is expected
as the frontal boundary shifts north of the area by Sunday evening.
Deep ridging expands into the area in its wake setting the table for
a hot and humid week upcoming across central Indiana. The core of
the ridge peaks with heights at 596-597dam by Tuesday and Wednesday
before slowly retrograding into the central Plains by next weekend.
Multiple days with highs in the 90s are expected 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 Thursday as the mid level heights begin to fall back. The
shift westward to the ridge axis will bring an increased risk for
convective clusters to impact parts of the area by next weekend.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 116 PM EDT Sat Jun 27 2026

Impacts:

- Brief VFR possible this evening, otherwise MVFR through 06Z

- IFR and worse conditions developing after 06Z in stratus and
  fog

- Scattered convection this afternoon into the evening

Discussion:

Ceilings will continue to lift this afternoon and could become VFR
for a period this evening. Otherwise, during the night ceilings will
fall once again in the moist atmosphere, with IFR and worse
conditions developing again mainly after 06Z Sunday. Fog will
develop again as well. Slow improvement will occur Sunday morning.

Scattered convection will develop this afternoon and will persist
into the evening. Isolated convection cannot be ruled out on Sunday,
but odds are too low to mention.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 8 PM EDT this evening for INZ067>069.

&&

UPDATE...50
AVIATION...50
DISCUSSION...Ryan

Hazardous Weather Outlook
National Weather Service Indianapolis IN
300 AM EDT Sat Jun 27 2026

INZ021-028>031-035>049-051>057-060>065-067>072-280800-
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-
300 AM EDT Sat Jun 27 2026

This hazardous weather outlook is for central Indiana.

.DAY ONE...Today and Tonight.

Scattered showers and thunderstorms are possible through tonight. A
few thunderstorms this afternoon and evening may produce damaging
winds, focused across the southwest half of central Indiana. Heavy
rainfall producing flooding will remain the primary concern.

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

Afternoon heat indices will rise into the upper 90s on Sunday then
above 100 degrees for much of next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated but any reports of flooding
through tonight would be appreciated.

&&

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

Ryan