067
FXUS63 KIND 121829
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
229 PM EDT Mon Oct 12 2026

.KEY MESSAGES...

- Very warm and mainly sunny weather with near record highs in the upper
  80s Tuesday

- A slow moving cold front will arrive Tuesday night and linger
  through Thursday night with widespread rain and scattered
  thunderstorms expected at times

- Cooler air arrives Friday and persists through the weekend,
  bringing widespread frost Saturday night

- Wind gusts peaking at 35 to 40 mph are possible Friday

&&

.DISCUSSION (This Evening through Monday)...
Issued at 229 PM EDT Mon Oct 12 2026

Near record breaking warmth is expected through Tuesday as a broad
upper level ridge expands across the Ohio Valley. A frontal boundary
will move into the area for midweek with periodic rain and storms
beginning Tuesday night and persisting through Thursday. Much cooler
air will expand across the region Friday into the weekend.

Rest of This Afternoon through Thursday

Warm and breezy afternoon in progress as pockets of mid and high
clouds drift across the region. 18Z temperatures ranged from the mid
70s east to the mid and upper 80s in the lower Wabash Valley.

Summer has reappeared across the Ohio Valley as a large ridge aloft
centers over the region. Southwest winds are advecting progressively
warmer and more humid air into the forecast area and will keep
temperatures well above normal over the next 36 hours or so. A few
locations may reach 90 this afternoon in the lower Wabash Valley
with 80s anticipated most all other locations. Mid and high clouds
will continue to move across the region at times through Tuesday
with breezy W/SW winds resuming Tuesday afternoon.

A frontal boundary across the northern Plains this afternoon will
slowly drift southeast and be across northern Indiana by Tuesday
afternoon. Deep moisture is lacking along the front with any
rainfall well to the north in the Great Lakes in the vicinity of a
stronger surface low early Tuesday. As the low continues into New
York state late Tuesday the frontal boundary will become
quasi-stationary and near parallel to the upper flow regime.

As the boundary slowly slides south into the forecast area Tuesday
night and Wednesday...much deeper moisture associated with Hurricane
Simon currently off the Mexican Pacific coast will advect northeast
into the region. This will serve as a catalyst to an expansion of
more widespread convection into the forecast area from the northwest
late Tuesday night and continuing into Wednesday with PWATS rising
to near 2 inches courtesy of the rich plume of tropical moisture
sidling up the frontal boundary. Multiple surface wave riding along
the front will further aid in widespread rain into Wednesday evening
before diminishing as the boundary settles near the Ohio River.

After a short break Wednesday night...additional showers and storms
will be possible Thursday as the front pulls back north in response
to a surface low ejecting out of the Rockies and increased upper jet
phasing. There remains at least some potential for a few stronger
storms...especially ahead of a strong cold front Thursday afternoon
and evening but uncertainty in cloud cover and available instability
makes that solution questionable at this point in time. 1 to 2
inches of rain is possible focused especially across the northern
half of the forecast area by Thursday evening

Temps...the combination of very warm 850 temps...breezy W/SW winds
and some form of compressional heating in advance of the frontal
boundary will aid in much of the forecast area warming into the
upper 80s Tuesday afternoon. A few spots reaching the lower 90s
remains a distinct possibility over the western portions of the
forecast area. The KIND record high of 86 degrees from 1975 is in
danger of being tied or broken. Clouds and periodic rain will keep
temps in the low and mid 80s Wednesday with a muggy airmass.
Thursday highs will largely be in the 70s before much cooler air
arrives for Friday and Saturday. Lows tonight and Tuesday night
especially will be more typical of mid-late summer peaking in the
mid and upper 60s.

Thursday Night Through Monday

The aforementioned cold front will sweep across the region Thursday
night and early Friday with any lingering threats for showers and
storms ending. In the wake of the frontal passage...the upper trough
will settle and amplify across much of the eastern half of the
country into the first part of the weekend before shifting east by
Sunday. A much cooler airmass will overspread the region as a result
but a change from model guidance over the last few days is that the
more progressive flow aloft would support temperatures recovering
more quickly late weekend into early next week.

The coolest air will advect into the area Friday and Saturday.
Intense cold advection combined with a sharp pressure gradient
behind the front will likely bring some of the strongest gradient
winds of the Fall so far Friday with gusts peaking at 35 to 40 mph.
Winds will relax Friday night into Saturday as a 1035mb surface high
moves across the region. Return flow will develop as early as Sunday
with the high moving east into the Mid Atlantic region. Deep
subsidence supports an extended period of mainly clear skies...
especially over the weekend as cyclonic flow aloft wanes.

Highs in the low and mid 60s are anticipated on Friday but the gusty
winds and diurnal cu development within the cold advection regime
will likely make that feel a bit cooler. Low level thermals support
mid and upper 50s for highs Saturday before recovery back to near 70
degrees by Monday. While a lack of boundary layer decoupling may
limit frost accrual to sheltered locales Friday night...confidence
is high in a widespread frost for much of the area on Saturday night
as lows fall into the 30s. Subfreezing temperatures are squarely on
the table for some of our normal cool spots as well Saturday night.
Lows will return to the mid and upper 40s by early next week.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1157 AM EDT Mon Oct 12 2026

Impacts:

- Southwest winds gusting up to 20kts this afternoon, then W/SW
  gusts to 20kts Tuesday afternoon

Discussion:

VFR conditions expected through the forecast period as central
Indiana resides under the influence of high pressure. Mid and high
clouds will pass through the region periodically over the next 24
hours. Southwest wind gusts will peak at 15 to 20kts this afternoon
at all the terminals...then veer to W/SW with similar peak gusts on
Tuesday. Light S/SW flow is anticipated tonight.

&&

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

&&

$$

AVIATION...Ryan
DISCUSSION...Ryan