144
FXUS63 KIND 151906
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
306 PM EDT Thu Oct 15 2026

.KEY MESSAGES...

- Numerous showers and scattered thunderstorms are expected into
  tonight

- Isolated severe storms are possible later this afternoon into the
  evening with potential for isolated damaging winds and tornadoes

- Strong post-frontal northwest winds will gust between 30 and 40
  mph late tonight into Friday

- Widespread frost and localized freeze conditions are likely
  Saturday night into Sunday morning

&&

.DISCUSSION (This evening through Thursday)...
Issued at 305 PM EDT Thu Oct 15 2026

This afternoon through Friday Night...

Current surface analysis depicts a low pressure system approaching
from the west while an associated warm front lifts north. Scattered
showers and a few embedded thunderstorms are now beginning to push
into central Indiana. Additional convective development can be
expected as the disturbance pushes across the area later today into
tonight.

Surface observations suggest the warm front is near far southern
portions of central Indiana where dewpoints are now in the lower
70s. The warm front will continue lifting northward towards the I-70
corridor. Low-level theta-e advection combined with diurnal heating
is expected to promote MLCAPE values of 750 to as high as 1250 J/KG
locally later this afternoon into the evening. Meanwhile aloft, a
mid-level jet streak from the parent trough continues to shift
eastward promoting stronger deep-layer shear. Increasing deep-layer
shear in addition to modest destabilization could result in isolated
severe thunderstorms. Effective shear values exceeding 40 kt are
expected which favors the potential for supercells or organized
storm clusters.

Enlarging low-level veering hodographs from the warm front lifting
north could support isolated tornadoes. Damaging wind gusts also
appear possible with organized storm clusters. One caveat limiting
confidence for the overall severe weather threat is uncertainty on
the degree of low-level buoyancy. Forecast soundings from the latest
CAMs depict poor lapse rates and relatively long-skinny CAPE
profiles. This suggest updraft strength may be limited. However,
even weak to modest low-level buoyancy in the favorable kinematic
environment could support isolated damaging wind gusts or tornadoes
so mesoscale trends will be monitored closely. Modest instability
will greatly limit the threat for severe hail though sub-severe hail
still appears possible.

Expect a cold front to move through late tonight advecting cooler-
drier air into the area. Look for precipitation chances to diminish
from west to east during the late overnight. Increasingly breezy
conditions are likely due to a tightening pressure gradient behind
the departing front and steepening low-level lapse rates. Wind gusts
between 25 to 35 mph should be common into Friday with sporadic
gusts as high as 40 mph. Steepening lapse rates and marginal low-
level moisture ahead of a backdoor cold front moving through late
Friday will promote scattered convective showers. The parent mid-
upper level trough overhead by this point should provide additional
forcing for convection.

Scattered lingering showers are possible early Friday night, mainly
across northwest portions of central Indiana, before the
aforementioned system shifts further east. Temperatures will drop
into the upper 30s and low 40s Friday night due to the additional
shot of cooler air. Patchy frost cannot be ruled out in sheltered
locations into Saturday morning, but breezy conditions should mostly
limit the threat elsewhere.

Saturday through the middle of next week...

A broad longwave trough will anchor across the eastern CONUS on
Saturday as a strong  surface anticyclone shifts from the Upper
Mississippi Valley southeastward across the Ohio Valley through
Sunday. The core of the cold pool will sit overhead Saturday,
keeping 850 mb temperatures around 0C to +2C. Despite clearing skies
and subsidence, daytime highs on Saturday will struggle to reach out
of the mid 50s, 10-15 degrees below normal.

Saturday night into Sunday morning represents the primary frost and
low-end freeze window of the period. The surface high center will
settle directly over central Indiana by 09Z Sunday, decoupling the
boundary layer and yielding calm winds, clear skies, and a very dry
ambient air mass with dew points in the upper 20s to low 30s. Strong
radiational cooling will cause overnight minimum temperatures to
drop into the lower to mid-30s across the entire forecast area, with
rural drainage basins and traditional cold spots likely dropping
near freezing. Widespread frost is expected across central Indiana,
and freeze conditions are probable in sheltered rural areas. Frost
and freeze headlines will likely be required as confidence remains
high across deterministic GFS, ECMWF, and their respective ensemble
suites.

The anticyclone will drift eastward toward the Mid-Atlantic on
Sunday, allowing insolation to rebound highs into the upper 50s and
lower 60s. Lows Sunday night will remain cool, in the upper 30s to
lower 40s, with patchy frost confined to far eastern rural valleys
before low-level winds back to the south.

For Monday through Wednesday, the synoptic pattern transitions as
upper-level ridging builds over the eastern states and a deep trough
carves out over the western CONUS. Steady south-southwesterly return
flow will drive a significant warm air advection regime across the
Ohio Valley. 850 mb temperatures will moderate to +10C to +13C,
pushing daytime highs into the upper 60s and lower 70s by early next
week. Overnight lows will moderate into the upper 40s to mid-50s.

Long range guidance generally supports quiet weather conditions
persisting through the middle of next week as surface high pressure
remains in control. Return flow should continue to provide a gradual
moderation in temperatures.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 141 PM EDT Thu Oct 15 2026

Impacts:

- Mostly MVFR ceilings are expected for all of this TAF period.
- Showers and storms expected this afternoon into the evening.
- Additional showers tonight, coverage decreasing after 15Z.
- Wind shifts through the period.
- Wind gusts 15-20kt tonight, up to 27kt after 15Z Friday.

Discussion:

IFR ceilings are widespread along and south of a slowly advancing
warm across southern portions of central Indiana early this
afternoon. Expect IFR conditions at KBMG to improve to MVFR around
19Z owing to increasing vertical motion with presence of convective
showers in the area. Elsewhere MVFR ceilings are expected to
continue through the period, with a few breaks possible at KHUF this
afternoon.

Attention turns to convection and likely impacts to terminals this
late afternoon/early evening. First round of TS currently moving
towards KHUF will be fairly isolated staying south of KIND and north
of KBMG. Larger convective line over western IL will move into the
terminals after 20Z. For this round, have added TEMPO wording for
TSRA at all but KLAF, with wind gusts to 30kt and IFR vis in TSRA.
This activity should be over by 00Z at all the terminals.

In the wake of this main convective line, winds will gradually shift
to W-SW with gusts to 20 kts expected overnight. The main front will
move towards the terminals between 06-12Z with winds becoming W-NW
with gusts over 20kt. A period of steady showers is expected along
and in the wake of the front, with activity expected to diminish to
VCSH by late morning. Stronger wind gusts will develop by late
morning with gusts as high as 27kts by midday Friday.


&&

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

$$

AVIATION...Crosbie
DISCUSSION...White/Melo