254
FXUS63 KIND 260549
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
149 AM EDT Thu Mar 26 2026

.KEY MESSAGES...

- Showers and thunderstorms likely late tonight

- Record temperatures in the lower 80s are expected on Thursday

- A round of strong to severe storms expected Thursday evening into
Thursday night, all hazards possible

- Cooler on Friday, with a warming trend resuming over the weekend

&&

.FORECAST UPDATE...
Issued at 859 PM EDT Wed Mar 25 2026

Mid level clouds continue to overspread and thicken across the
region this evening. An axis of showers has developed from west
central Illinois southeast into the lower Wabash Valley but with a
dry airmass present below 600mb...most of this is not reaching the
ground other than a few sprinkles. 01Z temperatures largely remained
in the 60s.

The combination of strengthening warm advection and an increasing
westerly low level jet into the area will contribute to gradual
moistening of the boundary layer into the early overnight as
dewpoints surge into the 50s. This will also allow for convective
development over eastern Illinois and western Indiana that will
become better organized after 04Z. As BL shear and low level SRH
increase into the overnight...expect continued expansion of
convective coverage and scattered thunderstorms across the
forecast area into the predawn hours. Instability will be limited
but present within the hail growth zone and small hail will be
possible with any stronger cells. Convection should clear the
forecast area to the east near or just after daybreak Thursday.

Lows overnight will hover in the upper 50s. Zone and grid updates
out.

&&

.SHORT TERM (This evening through Thursday)...
Issued at 306 PM EDT Wed Mar 25 2026

Quiet and warm weather today, then much hotter conditions on
Thursday with the threat for severe storms.

Satellite imagery shows partly cloudy skies over Indiana this
afternoon as high clouds stream in from the northwest. Conditions
are about to change as a few systems bring two chances for showers
and storms to the state over the next 24 to 30 hours. An area of low
pressure over the Upper Midwest today, shifts eastward tonight with
a trailing cold front to the north and a mid level wave passing
through Indiana overnight. With Indiana remaining in the warm sector
ahead of the front, expect moisture advection to increase overnight,
aided by a strengthening 40 kt low level jet aloft. A weak wave
ahead of the front is currently over Iowa and is expected to shift
into Indiana overnight tonight. While the atmosphere ahead of this
first wave is fairly dry according to local sounding data, enough
mid and upper level saturation should occur to support a cluster of
showers and thunderstorms within the 11pm to 6am timeframe. Forecast
soundings for tonight show modest amounts of elevated instability,
supportive of elevated showers and thunderstorms capable of
producing lightning and potentially small hail. Confidence is
highest in overnight storms within the 1 AM to 6 AM timeframe before
everything tracks east into Ohio.

THURSDAY RECORD HIGHS AND SEVERE WEATHER POTENTIAL

Confidence is increasing in the severe weather potential for
Central and North Central Indiana as the area has been upgraded to
an Enhanced Risk (level 3 of 5). Before the severe storms arrive,
another day of highs possibly exceeding 80 degrees is in the
forecast.

The aforementioned front stretches across the southern Great Lakes to
start the day with strong southwest flow and warm air advection
overspreading the region. While guidance is consistent in showing
widespread low 80s for Central Indiana on Thursday, there are a few
concerns which could limit overall highs. No matter what, high
temperatures will be 20+ degrees above normal for this time of year.
With that said, will have to watch how quick clouds clear from
morning convection and how thick mid and high level clouds are
during the afternoon. CAMs and hi-res models show the presence of
clouds during the day, despite a fairly dry warm sector with little
forcing for convective development midday. Thicker clouds may keep a
few spots in the 70s, while those locations with few cloud cover
make a run for the low 80s. In addition to near record high
temperatures, deep low level mixing into the low level jet will
promote afternoon wind gusts approaching 30 mph at times.

Focus now shifts to the severe threat Thursday night. Guidance
remains in very good agreement depicting widespread convective
development after about 8pm Thursday along the front in Northern
Illinois and Indiana. Shear right along and ahead of the front
ranges from 35 to 50 kts through the column; Shear vectors are
roughly, but not quite, parallel to the aforementioned cold front.
This should allow initial development to be somewhat discrete.
However, strong frontal forcing combined with the nearly parallel
flow should cause activity to grow upscale rather quickly.

Model soundings show deep layer CAPE of around 1500 J/Kg with an
equilibrium level (EL) near 12km. Long curved hodographs support
supercell development initially especially with initial discrete
convection; however given the orientation of the shear, expect
discrete cells and supercells to congeal into a line as the night
progresses. Given very steep mid and upper-level lapse rates between
7-8 C/Km, high ELs, strong shear...large to very large hail is
possible with initial development. A damaging wind threat may then
emerge as storms grow upscale. The curved nature of the hodograph
right along the front, as well as rich low-level moisture, may allow
for a tornado risk earlier in the evening for Northern Central
Indiana, but this could be mitigated by fast upscale growth and the
strength of the front.

A flooding risk is also present as storm motions allow for training
along the west-east oriented front. A few pockets of 1 to 3 inches
of rainfall is likely for locations receiving repeated rounds of
heavy storms. At the moment the greatest flooding threat is also
along and north of I-70, before storms begin to weaken overnight and
shift southward.

&&

.LONG TERM (Thursday night through Wednesday)...
Issued at 306 PM EDT Wed Mar 25 2026

Central Indiana will remain under the influence of an upper trough
Friday and Saturday, with cooler air in place. Highs will be in the
40s to middle 50s, and lows Saturday morning will generally be in
the upper 20s. Rain may linger Friday in the south as the cold front
exits. For Friday night into Saturday, high pressure will be in
control, providing quiet weather.

For Sunday into mid-week next week, an upper ridge to the south will
attempt to build north into the area. However, central Indiana will
remain on its periphery. The ridge will get close enough to
likely bring temperatures into the 70s for Monday into Wednesday.

However, energy riding around the upper ridge will bring forcing at
times. In addition, a surface front may be in the vicinity
periodically, depending on how far north the ridge pushes the warmer
air. These will create daily chances for rain Monday into Wednesday
of next week. Details will have to be ironed out when the exact
setup of the features becomes clearer.

Beyond mid-week next week, an active pattern may setup with central
Indiana potentially under southwest flow aloft, which will allow for
more systems to impact the area.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 149 AM EDT Thu Mar 26 2026

Impacts:

- Showers and thunderstorms expected through 11Z this morning

- Peak wind gusts at 25 to 30kts Thursday afternoon

- Intense convection will impact the terminals after 22Z today,
  primarily at LAF/IND initially before shifting south

Discussion:

Clouds are increasing from the west as a weak wave aloft approaches.
Convection is developing in eastern IL and will impact each of the
terminals through 08-11Z this morning. Marginal low level wind shear
is possible for a couple hours, but confidence is too low to include
in the TAFs at this time. Southwest winds have dropped to near 10kts
and may back slightly to southerly over the next few hours briefly.

Peak wind gusts between 25 to 30 kt are expected this afternoon.
Robust convective development is expected along a cold front across
the lower Great Lakes by this evening. Look for storms to push south
into central Indiana during the evening and overnight. Primarily
LAF/IND will be impacted first with initial storms, but additional
convection will impact the other sites as well into the overnight
hours.

&&

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

$$

UPDATE...Ryan
SHORT TERM...CM
LONG TERM...50
AVIATION...Melo