427
FXUS63 KIND 241342
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
942 AM EDT Fri Apr 24 2026

.KEY MESSAGES...

- Potential for showers/storms early this morning, better chances in
  the afternoon and evening

- Dry and quiet this weekend

- Strong to severe storms likely Monday into Monday night

&&

.FORECAST UPDATE...
Issued at 942 AM EDT Fri Apr 24 2026

Scattered showers continue to develop across the region this morning
in advance of a frontal boundary approaching from the west. 13Z
temperatures were in the mid and upper 60s with an abundance of
clouds.

Convective coverage will increase into the afternoon as the boundary
moves into the forecast area but a lack of appreciable instability
within a low shear environment will keep a cap on overall convective
intensity into the afternoon. There remains a slightly higher
ceiling for stronger cells to pull down gusty winds across eastern
Indiana by mid to late afternoon but anticipate MLCAPE values no
higher than 500-1000 j/kg which will keep this risk isolated at
best. Scattered convection will linger into the first part of the
evening before shifting east.

Surface heating will be hampered by extensive mid and high level
clouds which will be further aided by leftover convective debris
from the storms Thursday evening and earlier this morning to our
west. May see some peaks of sun this afternoon but cloud cover will
remain plentiful into the evening.

Highs in the mid to upper 70s for most locations are likely for the
afternoon. Zone and grid updates out.

&&

.DISCUSSION (Today through Thursday)...
Issued at 302 AM EDT Fri Apr 24 2026

A cold front is approaching Indiana from the west, and extends from
Iowa southward through Missouri as of 2am. Extensive shower and
thunderstorm activity is occurring along the entirety of the front.
This activity has been gradually weakening as it outruns its source
of lift and encounters a more stable air mass. Additionally,
available wind shear greatly diminishes with eastward extent,
allowing ongoing storms to quickly become cold pool dominant. CAM
guidance is in good agreement showing these storms diminishing as
the reach Indiana, with some showing complete dissipation.

The majority of guidance shows at least some isolated to scattered
shower activity arriving as early as 12z. We will include chance
PoPs through the morning hours to account for this. Shower and storm
chances then increase during the afternoon hours as daytime heating
allows for some modest destabilization (MLCAPE 500-1000 J/Kg). Wind
shear is modest as well, roughly 20-30kt through the depth of the
column. From a storm-relative standpoint, however, shear is almost
non-existent. As such, storms today should display mostly single
cell to multicell characteristics.

Taking a look at hazard potential, the overall threat seems low.
Model soundings show some dry air in the lower levels, which may
allow for a brief downburst within stronger cells. Additionally,
should storms congeal into a cluster than cold pool dynamics could
allow for a brief surge capable of damaging winds.

Aside from storm activity, increasing clouds and precipitation
should keep temperatures fairly muted compared to yesterday. Highs
in the 70s will be common. The aforementioned cold front arrives just
after midnight Saturday, with clearing skies and a wind shift to
northerly. Cooler air gradually filters in, with high temps
remaining in the low to mid 70s for the next several days. Expect
nightly low temperatures in the upper 40s (north) to mid 50s (south)
through the weekend.

MONDAY SEVERE WEATHER POTENTIAL

Attention then shifts to the significant synoptic event unfolding
for Monday. Recent global model guidance, including the GFS and
ECMWF, has shown remarkable consistency in depicting a vigorous,
negatively-tilted mid-level wave ejections out of the Southwest.
This feature is expected to induce rapid surface cyclogenesis over
the Central Plains by Sunday night, with the resulting sub-995mb
surface low tracking toward the Upper Mississippi Valley by Monday
afternoon. This will result in a significant northward surge of Gulf
moisture, with dewpoints expected to reach the mid 60s as far north
as the I-70 corridor.

Scientifically, the Monday setup is particularly concerning due to
the coupling of strong kinematics and significant instability.
Guidance indicates a 55-65 kt LLJ will be in place across central
Indiana by Monday afternoon, which will not only provide intense low-
level moisture transport but also contribute to enlarged, curved low-
level hodographs. 0-1 km SRH values exceeding 250 m2/s2 are
currently being modeled, which would be more than sufficient for a
tornado threat if storms can remain discrete. CAPE values in the
2000-3000 J/kg range appear plausible given the WAA regime. While
some global models show a faster progression with a QLCS along the
cold front, the potential for pre-frontal supercells within the open
warm sector cannot be ruled out, especially given the degree of
forcing from the approaching shortwave.

Furthermore, the high PWAT values approaching 1.5 to 1.7 inches,
which is near the 90th percentile for late April, will introduce a
risk for flash flooding. The orientation of the LLJ relative to the
advancing front suggests the possibility of training cells or back-
building convection during the Monday night period. As the primary
surface low moves into the Great Lakes by Tuesday, a powerful cold
front will sweep through the Ohio Valley, effectively shunting the
moisture south and ushering in a much cooler, drier airmass for the
middle of next week. In the wake of this system, GEFS and EPS means
show a period of high-pressure dominance with temperatures returning
to near or slightly below seasonal norms.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 639 AM EDT Fri Apr 24 2026

Impacts:

- Wind gusts around 20-25 kt this afternoon
- Showers and possibly a thunderstorm today
- Wind shift to northerly as cold front passes tonight

Discussion:

A cold front is approaching from the west and will arrive late in
the TAF period. Shower and thunderstorm activity is associated with
the front, which extends from northern Illinois south through
Missouri. Over Indiana, only thin high cirrus has been observed as
of this writing. Clouds are expected to increase, thicken, and lower
with time as the front approaches.

Showers and storms along the front should gradually weaken, but not
completely dissipate, as they reach Indiana by 15z. As such, we will
include a VCSH group in the TAFs to start before introducing a
PROB30 for thunderstorms in the afternoon. Most guidance shows
thunderstorm activity redeveloping during the afternoon, especially
from IND to BMG eastward.

Ceilings remain VFR for most of the day, gradually lowering during
the afternoon as shower/storm activity increases. Stratocumulus may
persist into the night with gradual clearing by the end of the TAF
period.

Winds remain out of the south through this morning, before becoming
southwesterly during the day. Gusts may top 20-25kt at times. Winds
diminish and become westerly as the front passes through. Afterward,
roughly around 04z-06z, winds become northerly and increase slightly
as the cooler air mass behind the front arrives. Mainly clear skies
and northerly winds around 10kt persist through Saturday.

&&

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

&&

$$

UPDATE...Ryan
AVIATION...Eckhoff
DISCUSSION...White/Eckhoff