498
FXUS63 KIND 261336
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
936 AM EDT Sat Jul 26 2025

.KEY MESSAGES...

- Heat Advisory across portions of central and southern Indiana
  through tomorrow evening

- Dangerous heat continues into early next week with additional days
  of greater than 100 degree heat indices likely

- Periodic showers and storms through the weekend with isolated
  flooding and strong winds

&&

.FORECAST UPDATE...
Issued at 936 AM EDT Sat Jul 26 2025

An abundance of mid and high level clouds lingered over much of the
forecast area this morning from the remnants of early morning
convection across the northern part of the state and additional
thunderstorms currently over western Illinois near the Mississippi
River. Have seen a few showers across the forecast area already
otherwise it was dry. 13Z temperatures ranged from the mid 70s to
lower 80s.

Bit of a convoluted forecast for the rest of the day that starts
with the ongoing cloud cover. More substantial clearing exists from
central Missouri into south central Illinois with the expectation of
that spreading east across the southern half of the forecast area by
early afternoon. Further north however...the broad mid and high
level clouds associated with the ongoing convection may keep skies
in a mostly cloudy state well into the afternoon. This would likely
have an impact on eventual highs and perhaps available instability
for convection later on.

Speaking of convection...mesoscale features will be critical again
as they have been the last few days on where storms develop. A
remnant outflow boundary from storms earlier this morning has
settled in a west-east fashion south of I-70 and is likely
influencing the isolated development we have already seen so far
this morning across the central portion of the forecast area. This
is likely to be a focal point for renewed convective development
this afternoon as convective temps are reached. Convection will
again be heavily driven by instability and of a pulse intensity in
the absence of shear. While localized wet microbursts remain a
threat from any collapsing downdraft...torrential rainfall and cloud
to ground lightning will remain the primary concerns for outdoor
activities this afternoon and evening. New model data this morning
continues to highlight a potential for more organized convection to
move into the Wabash Valley from the west by mid to late evening and
will need to monitor trends through late day.

Highs will again be in the upper 80s and lower 90s this afternoon...
but will need to monitor cloud coverage as heating could be limited
slightly over northern counties. Will maintain the Heat Advisory
across the southern half of the forecast area with heat indices
approaching 105 degrees. Zone and grid updates out.

&&

.SHORT TERM (Today and tonight)...
Issued at 255 AM EDT Sat Jul 26 2025

Surface analysis early this morning shows a poorly defined frontal
boundary draped from Central IL northeast to northern Indiana and
MI. Convection over IL was present near this boundary and was
pushing northeast along it. High pressure was found north of the
boundary over Ontario and a second area of high pressure was found
over the southeastern states. The southern high was resulting in a
continued lower level flow of hot and very humid gulf air streaming
into the Ohio Valley. Aloft, water vapor imagery shows a plume of
tropical moisture streaming across TX, northward to IA and MO, and
then northeast to IL, NRN Indiana and MI. the ongoing storms were
staying confined mainly to underneath this plume. An upper level
high pressure system was found over the SE states, resulting in ring
of fire like effects over IL into northern Indiana.

Today...

Little overall change will be expected today across Central Indiana.
The very hot and humid air mass in place across the area will
continue to control our weather as the upper high is suggested to
strengthen and steer potential forcing dynamics and the tropical
plume farther to the north. Forecast soundings once again show a
favorable signature for diurnal convection with steep lapse rates
and CAPE values over 2800 J/KG. Pwats also are favorable with values
in excess of 1.90 inches. HRRR also suggests afternoon shower and
storm development due to these favorable conditions. Thus will once
again include afternoon pops for hit and miss diurnal storms. Heavy
rain will be possible considering the very moist air mass. HRRR
suggests storms dissipating by early evening.

Again high dew points in combination with highs around 90 will
result in heat index values in the low 100s. Ongoing Advisory will
remain.

Tonight...

A few lingering diurnal storms will be possible in the evening
before the rest of the evening looks to remain mostly dry. Models
suggest an organized area of convection and forcing well to the
north of Central Indiana, over northern Indiana and Michigan during
the evening, However, the tail of this system may trigger some
overnight convection across Central Indiana. Confidence for this is
low, but given our continued warm and humid air mass, small chances
for pops will still be necessary for now. Lows overnight will
remain warm and humid, in the middle 70s.

&&

.LONG TERM (Sunday through Friday)...
Issued at 255 AM EDT Sat Jul 26 2025

For much of the long term, central Indiana will sit between an upper
high meandering over the SE states into the central plains and a
large upper low over Canada. This will place the area in a hot and
humid pattern with almost daily chances for showers and storms.
Severe weather looks unlikely with a lack of shear, but can`t rule
out an isolated downburst causing damaging winds. Highs through
midweek are expected to range from the upper 80s to low 90s. With
ample humidity to continue, heat headlines will likely continue as
heat indices near 100-110 will be probable.

By mid to late next week, the upper low over Canada will dip
southward, bringing cooler and drier air to the region. Highs for
late week into the weekend may even max out in the upper 70s for a
day or two, providing a relief to the heat.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 534 AM EDT Sat Jul 26 2025

Impacts:

- Scattered convection developing again this afternoon

Discussion:

Overall Little change in the ongoing TAF forecasts. VFR is expected
for much of the period.

Waning convection over IL and Northern Indiana has resulted in some
high CI debris clouds. These clouds will drift across the TAF sites
early in the forecast period.

The very warm and humid air mass will remain over Central Indiana
today, and once again forecast soundings are favorable for diurnal
convection. As daytime heating begins, CU development will start by
mid morning. By early afternoon VFR Cigs due to CU is expected. HRRR
suggests isolated shower and storm coverage thereafter as highs in
lower 90s are reached. Confidence for specific timing or locations
of any storms is small, so just a period of VCTS has been used for
now during the most favorable hours for storms.

Any TSRA that strikes a TAF site may result in brief MVFR to IFR
conditions.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for INZ043>047-051>057-
060>065-067>072.

&&

$$

UPDATE...Ryan
SHORT TERM...Puma
LONG TERM...KF
AVIATION...Puma