289
FXUS63 KIND 221927
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
327 PM EDT Wed Apr 22 2026

.KEY MESSAGES...

- Isolated strong storms are possible late this afternoon/evening,
  with gusty winds and hail across far N-NE portions of central
  Indiana.

- Rain and thunder chances Friday and Friday night again next and
  again late Monday. Threat for severe weather is greatest on
  Monday.

- Near to above normal temperatures through early next week.

&&

.MESOSCALE UPDATE...
Issued at 224 PM EDT Wed Apr 22 2026

A subtle shortwave trough moving through the Great Lakes, combined
with a pocket of deep moist convergence supported the development of
convection over southern Lake Michigan several hours ago. This
activity has recently moving into NW Indiana. Deep shear vectors
support a SE motion into NE portions of the state where a moderate
instability axis exists (MLCAPE from 1500-2000 J/K). Surface
analysis shows dewpoints along this axis running from 58-62F which
include the far north-northeast portion of central Indiana. Storm
mode should be mostly multicellular, with the threat for marginally
severe hail fairly low, and mainly supported by fairly steep mid
level lapse rates around 7 C/KM.

However any localized backing of the surface winds may support
effective bulk shear values to briefly peak up above 35 kts with
greater updraft intensity and hail approaching 1 inch in diameter.
An axis of DCAPE from 800-900 J/KG extends across northern portions
of central Indiana into NE Indiana. With storm mergers ongoing and
expected to continue, damaging winds appears to be the primary
threat. Current activity is expected to get very close to far NE
portions of central IN in the 22-00Z time period. Some of the CAM
guidance suggests that activity may build SW into the instability
axis and graze more of the northern counties, but lack of
substantial tcu development on the SW flank and copious low cloud
deck in this area limits confidence on this scenario.

&&

.DISCUSSION (This evening through Wednesday)...
Issued at 326 PM EDT Wed Apr 22 2026

Rest of this afternoon/early evening....

See the most recent mesoscale update for current thinking on storm
evolution and severe weather potential impacts to far north-NE
portions of central Indiana late this afternoon.

Tonight...

With loss of daytime heating and passage of the weak shortwave
trough, thunderstorm chances are expected to end by 04Z. Mostly
clear skies and light winds will be the rule as high pressure
centered over the SE states becomes reinforced with the ridge axis
from the surface up through mid levels extending across the region.

Thursday...

A shortwave trough will eject out of the Rockies into the Plains on
Thursday. As surface pressure falls increase over the MS/MO valleys,
increasing gradient winds will result with S-SW wind gusts from 20-
25 mph during the afternoon with temperatures once again well above
normal from 75-80F. Convection will rapidly develop and intensify
over the Plains during the afternoon along an associated cold front.

Thursday Night...

Convection will move quickly east into the MS valley supported by a
40-50 kt low level jet and ample instability (MUCAPE 1000-2000 j/kg).
There is varying degrees of placement on the leading edge of
precip/TS potential into western portions of central Indiana towards
12Z Friday. Have opted with a slightly slow solution generally
slower than the HREF blend and more in line with the operational
Euro model with only slight chance late.

Friday/Friday Night...

Cloud cover and potential for remnant showers/TS and consequent
marginal mid level lapse rates will likely be the mitigating factors
for a more substantial severe threat. However, with a frontal
boundary crossing central Indiana during the early-mid afternoon,
and moderately strong kinematic fields, greater destabilization may
favor a slight risk for severe weather in later SPC outlooks. In the
wake of the system Friday, there is some indication of an MCV coming
out of KS/MO to graze southern central Indiana Friday night. Have
upped PoPs across southern portion of the forecast area to account
for this potential.

Saturday through Sunday...

Fairly quiet weather will be the rule during the period as high
pressure build southeast behind a cold front and intensifies over
the Great Lakes. Another strong mid-upper level shortwave will move
into the western CONUS during the period as a prelude to more active
weather for central Indiana.

Monday...

A vigorous and fast moving shortwave trough will move out of the
Plains and into the MS valley during the day. Fairly strong
kinematic fields combined with sufficient instability favor the
threat for all hazards severe weather along a cold front and
potentially pre-frontal confluence bands as the primary surface low
pressure moves into the western Great Lakes. Present indications are
this activity will push towards central Indiana towards early
evening, but this far out timing remains uncertain. SPC has a Day 5
slight risk out just south of the forecast area. Expectation is for
this risk to eventually be shifted to include much if not all of
central Indiana in later outlooks.

Tuesday/Wednesday...

Quieter weather returns Tuesday with temps cooling to near normal
and drier conditions in the wake of Monday/Monday night convective
event. Another shortwave is progged to move out of the desert SW
into the central and southern plains with some potential for
showers/TS for central Indiana late Wednesday. Timing and coverage
is even more uncertain for this event, so for now low end PoPs seem
reasonable.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 104 PM EDT Wed Apr 22 2026

Impacts:

- Scattered convection possible this evening at KLAF.
- Wind gusts around 20kt this afternoon and again Thurs afternoon.

Discussion:

Fairly tranquil conditions at present across the TAF sites with VFR
conditions and winds generally out of the SW from 8-12 kts with a
few gusts around 20 kts.  Convection will increase over northern
portions of Indiana while moving SE this afternoon. There is a
chance of isolated thunderstorm development at KIND, but chances are
low enough that PROB30 will be dropped from the TAF forecasts.
However, there is still enough of a chance for TS at KLAF to warrant
continued mention in the TAF for the late afternoon/early evening.

Overnight, convection will diminish fairly quickly with loss of
heating. Winds will be generally 4-6 kts from the SW with mostly
clear skies. Thursday will see VFR conditions with gradually
increasing SW winds during the afternoon with a few gusts around 20
kts.


&&

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

$$

MESOSCALE...Crosbie
AVIATION...Crosbie
DISCUSSION...Crosbie