316
FXUS63 KIND 131324
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
924 AM EDT Tue Oct 13 2026

.KEY MESSAGES...

- Record warmth today with highs reaching the upper 80s to low 90s

- Multiple rounds of rain and scattered thunderstorms Tuesday
  night through Thursday night

- Sharply colder Friday with northwest wind gusts of 30 to 40 mph

- Frost and localized freeze potential late Saturday night into
  early Sunday morning

&&

.FORECAST UPDATE...
Issued at 924 AM EDT Tue Oct 13 2026

Area of mid level clouds have develop across the northern half of
the forecast area this morning in response to a subtle wave aloft
passing through the region. A few light returns have popped up over
north central Indiana and likely getting a few showers despite the
high cloud bases. 13Z temperatures ranged from the mid 60s to the
lower 70s.

Have inserted isolated showers into the forecast for the next 2-3
hours over northern parts of central Indiana but as the wave aloft
shifts east...expect all of that to be out of the area by noon. The
primary focus for the rest of the day is on the late season heat and
what if any impact the ongoing mid level clouds might have on max
temps this afternoon. Much of the southern half of the forecast area
should remain largely free of the mid level clouds while further
north anticipate more sunshine by the afternoon as the
aforementioned upper wave departs off to the east.

Low level thermals remain strongly supportive of max temps in the
upper 80s to low 90s which are quite remarkable for mid October. The
record high of 86 at KIND is expected to be broken and if in fact
temps can get to 90 degrees...this would mark the latest 90 degree
day on record in Indy as well. Going deeper into the period of
record if KIND can get to 88 degrees today combined with the 88
degree high that occurred back on March 22...it would mark a 205 day
period between the first and last 88 degree day this year which
would shatter the previous record of 155 days between 5/1/1951 and
10/4/1951. Very on brand for 2026 with all of the weather records
that have been broken throughout the year.

Zone and grid updates out.

&&

.DISCUSSION (Today through Monday)...
Issued at 130 AM EDT Tue Oct 13 2026

Today Through Wednesday.

Broad mid-level ridging centered over the Southeast expands across
the Ohio Valley today while a deep trough digs across south-central
Canada and the Upper Midwest. South-southwesterly boundary layer
flow downstream of an approaching surface cold front will reinforce
warm thermal advection across central Indiana. Forecast soundings
indicate 850mb temperatures climbing to 16-17C with deep diurnal
mixing up to 800mb. The combination of WAA and plenty of sun will
allow for temperatures to rise into the upper 80s to potentially low
90s, breaking records. Momentum transfer within the mixed layer will
support sustained southwesterly surface winds of 15 to 20 mph with
gusts peaking between 25 and 30 mph.

The synoptic surface cold front will decelerate Tuesday night as
upper-level flow orients quasi-parallel to the boundary. Mesoscale
guidance, including the HRRR and HREF members, focuses initial pre-
frontal convective development across northwestern counties after
midnight as a 35 kt low-level jet intercepts the frontal zone.
Instability remains largely elevated and diurnally capped, with
MUCAPE values generally under 500 J/kg, limiting severe convective
potential to isolated general thunder outside of a low-end threat
for gusty winds.

The frontal zone sags into central Indiana Wednesday, serving as a
focus for precipitation as mid-level frontogenesis tightens.
High-resolution guidance shows precipitable water values surging
to 1.4 to 1.6 inches along the boundary, exceeding the 90th
climatological percentile for mid-October. Right-entrance region
upper jet dynamics and continuous moisture transport will support
widespread rain and embedded convective clusters throughout
Wednesday afternoon and Wednesday night. Afternoon highs Wednesday
will exhibit a marked thermal gradient, ranging from the low to
mid- 60s in the northwest behind the front to upper 70s and lower
80s across south-central Indiana.

Thursday Through Monday.

A secondary shortwave rotates through the base of the deepening
eastern longwave trough Thursday, inducing a weak wave of low
pressure along the stalled baroclinic zone over the Ohio Valley.
Strong multi-level deformation and mid-level FGEN combined with deep
moisture will maintain high PoPs through Thursday evening before the
boundary finally clears the forecast area to the southeast. Multi-
model ensemble consensus aligns with WPC guidance depicting
widespread event-total QPF between 1.00 and 2.00 inches across
central Indiana, providing much-needed drought relief.

Cold air advection strengthens drastically Thursday night into
Friday behind the frontal passage as an amplified 500mb polar trough
settles over the Great Lakes and eastern CONUS. An intense surface
pressure gradient between the departing low and a 1028mb Canadian
surface high will combine with steep low-level lapse rates to
promote deep boundary layer mixing on Friday. Sounding profiles show
35 to 40 kt winds at the top of the mixed layer, which will easily
translate to surface gusts of 35 to 40 mph throughout Friday
afternoon. Highs on Friday will be held in the mid-50s to near 60F
despite clearing skies as a result of the strong CAA.

The core of the thermal trough crosses the region Friday night into
Saturday, with 850mb temperatures dropping to between -2C and
0C. Highs Saturday will struggle to reach the low to mid-50s
under cold northwest flow. The primary frost/freeze window remains
Saturday night into early Sunday morning. The Canadian surface
anticyclone settles directly over the Ohio Valley by 09Z Sunday,
resulting in clear skies and a decoupled wind field. Radiational
cooling within this dry continental airmass will cause surface
temperatures to drop into the low to mid-30s across central
Indiana. Widespread frost appears likely across rural and
sheltered areas, with a localized freeze probable in typically
colder drainage basins.

The surface ridge axis shifts toward the Mid-Atlantic on Sunday and
Monday, allowing low-level flow to veer to the south-southwest.
Height rises aloft downstream of a Western trough will promote
thermal moderation, returning highs to the lower 60s Sunday and
upper 60s by Monday under dry conditions.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 547 AM EDT Tue Oct 13 2026

Impacts:
- Southwesterly winds to gust up to 20kt 16Z to 23Z

Discussion:

VFR conditions expected through the TAF period with only passing
cirrus through the day today. Southwesterly winds will gradually
ramp up in speed through the morning hours with gust up to 20kt at
times through the afternoon and early evening. Those winds will then
drop back to near calm tonight with high clouds gradually increasing
in coverage through the night ahead of rainfall tomorrow morning.

&&

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

&&

$$

UPDATE...Ryan
AVIATION...White
DISCUSSION...White