647
FXUS63 KIND 160105
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
905 PM EDT Wed Apr 15 2026

.KEY MESSAGES...

- Strong storms possible after midnight

- Generally dry Thursday and Friday with low rain chances Thursday
  afternoon

- Near record warm temperatures expected through Saturday with
  multiple days in the 80s and lows in the 60s

- Much cooler Sunday into early next week with the potential for
  frost

&&

.FORECAST UPDATE...
Issued at 904 PM EDT Wed Apr 15 2026

Surface analysis this evening shows a trough in place from WI to OK.
GOES19 Shows convection along and near this trough. Moderate
southwest flow was in place across Indiana ahead of this feature.
Aloft, vapor shows a plume of moisture streaming into the plains and
Ohio Valley. These features were coming together to generate light
rain showers across Indiana. CAPE across central Indiana has become
rather limited per SPC mesoanalysis pages and recent radar returns
also reflect that as rain intensity across central Indiana the past
few hours has diminished. Looking farther west, stronger convection
was found over MO and IA.

CAMs continue to struggle with the timing and evolution of these
waves beyond a few hours out. Nonetheless, the convection upstream
is still projected to push eastward toward Indiana overnight and
into Thursday morning. Forecast soundings also trend toward some
deep saturation overnight as these feature pass. Due to less
favorable instability across our area, stronger storms are not
expected. Caveat remains a 40knt LLJ that will be present overnight.
Thus will use relative low pops through about 07Z, mainly across the
western area, and then higher pops thereafter as the main forcing
from the west looks to arrive. Given your clouds, rain and good
mixing on southerly winds, lows in the middle 60s are expected.

&&

.DISCUSSION (This evening through Wednesday)...
Issued at 103 PM EDT Wed Apr 15 2026

Overview.

An active and progressive spring pattern remains firmly in place
across the Ohio Valley with a weak MCV moving across northern
Indiana and a broader surface low currently across Iowa. This system
is embedded within a broad southwesterly flow regime that is
characterized by an 80-90 kt upper-level jet. As the LLJ ramps up
this evening into tonight, thunderstorms are expected with the
potential for damaging wind gusts with the strongest storms. While a
brief period of ridging will bring a temporary reprieve on Friday, a
strong cold front is expected to sweep through the region on
Saturday with additional thunderstorms expected. This transition
will usher in a much cooler airmass for the early part of next week,
introducing potential frost concerns for the local area.

Through Tonight.

The latest water vapor imagery and regional radar mosaics highlight
an MCV currently moving through northern Indiana. This feature is
expected to remain north of the forecast area with a dissipating
boundary closer to the I-70 corridor. Recent high-resolution model
guidance keeps the convection this afternoon north of the forecast
area associated with the MCV with additional development across
Missouri and western Illinois towards 18-20Z as skies gradually
clear and instability increases. Diabatic heating is already pushing
temperatures into the upper 70s with dewpoints in the low 60s. This
environment should yield MLCAPE values of 1200 to 1800 J/kg by peak
heating. Effective bulk shear of 35-45 kts will be sufficient for
organized multicellular structures if convection can hold together
as it moves further into Indiana after 00Z.

The primary threat with this activity will be damaging wind gusts.
High DCAPE values exceeding 800 J/kg and steep low-level lapse rates
will support efficient downward momentum transfer in collapsing
cores. A secondary round of convection is likely as the LLJ cranks
up to 40-50 kts after 06z. This will sustain elevated convection
through the overnight hours, though the severe threat should
gradually wane as the boundary layer stabilizes after sunset.

Thursday through Friday Night.

The aforementioned MCV is forecast to exit to the east by late this
evening, leaving behind a trailing surface trough. While scattered
showers remain possible on Thursday, the overall trend will be
toward drying as subsidence increases across the region. Friday
looks to be the warmest and driest as strong warm air advection
ahead of the next major trough pushes 850mb temperatures toward the
90th percentile of climatology. Highs in the low to mid 80s are
probable, and record high minimums in the 60s are also at risk as a
humid airmass remains entrenched across the state.

Saturday through Wednesday.

GEFS and EPS output shows high confidence in a significant pattern
shift beginning on Saturday. A deep longwave trough will eject out
of the Rockies, and ensembles are in good agreement on a strong cold
front crossing Indiana during peak heating. Given the robust
dynamics associated with this system, another round of severe
weather is possible, although timing differences between the faster
GFS and slower ECMWF solutions still need to be resolved.
On the backside of the front, a 1030mb surface high will slide south
from Central Canada. Ensemble means indicate temperatures dropping
15-20 degrees below normal for Sunday and Monday. Lows Sunday night
and Monday night are currently projected to be in the low to mid
30s. Those with sensitive vegetation should prepare for potential
frost or freeze headlines as the seasonably cold air settles in. The
EPS members suggest a gradual moderating trend by Tuesday and
Wednesday as the high shifts east, returning the region to
southwesterly flow and more tranquil conditions to start the mid-
week period.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 705 PM EDT Wed Apr 15 2026

Impacts:

- Mainly VFR conditions this TAF period.
- Low chances for TSRA this evening, more likely after 08Z
- MVFR to IFR vsbys/cigs during any TSRA

Discussion:

VFR conditions remain across the TAF sites this evening as mid and
high cloud continue to stream across Indiana within the southwest
flow aloft. A wave of weak convection passing across Indiana will
bring some light rain showers and isolated thunder to IND/HUF and
BMG this evening.

More organized showers and storms will be possible overnight as a
cold front over the plains approaches and combines with a moderate
LLJ. Forecast soundings suggest deep saturation overnight as this
wave passes, but CAM`s haphazard guidance is not building confidence
on precise timing or locations. Thus VCSH windows have been used for
much of the night.

As the front passes on Thursday morning, a VFR conditions will
become firmly set as winds shift to the WSW.


&&

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

$$

UPDATE...Puma
AVIATION...Puma
DISCUSSION...White