582
FXUS63 KIND 121557
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1157 AM EDT Mon Oct 12 2026

.KEY MESSAGES...

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

- A slow-moving cold front will arrive Wednesday, bringing
  widespread rain and scattered thunderstorms through Thursday night

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

&&

.FORECAST UPDATE...
Issued at 912 AM EDT Mon Oct 12 2026

Fog coverage has steadily diminished from the west since around 10Z
with only small pockets of fog lingering as of 13Z. Let the Dense
Fog Advisory expire as a result. 13Z temperatures were largely in
the upper 50s with high clouds drifting across the region.

Broad upper level ridging expands across the Ohio Valley today with
breezy and very warm conditions for this afternoon as southwest flow
increases. Cirrus will continue to move across central Indiana
throughout the day as temperatures soar into the middle and upper
80s during the afternoon. The record high for today at KIND of 86
from 1879 is in play. Expect winds gusting to around 20-25mph at
times this afternoon as well.

Zone and grid updates out.

&&

.DISCUSSION (Today through Sunday)...
Issued at 130 AM EDT Mon Oct 12 2026

Today Through Tuesday.

Areas of fog have developed across much of central Indiana and will
continue to spread in coverage through daybreak with clear skies and
calm winds across the forecast area. Fog generally remains non-dense
but with the increasing coverage, have elected to issue a Special
Weather Statement. Will continue to monitor observational trends
going forward and will issue a Dense Fog Advisory if conditions
warrant.

Strong low-level WAA will overspread the area after daybreak as
surface high pressure shifts off the Mid-Atlantic coast and a
deepening upper trough moves across the Northern Plains. The
tightening regional pressure gradient will drive gusty southwesterly
surface winds of 15 to 25 kt across the forecast area. Model
soundings show strong boundary layer mixing up to 850 MB, where
temperatures reaching 15-17C will support afternoon surface highs
in the mid to upper 80s. These values will threaten established
record highs at IND (86F) and approach the 90F mark in the Wabash
Valley. Deep subsidence and dry mid-level air will maintain
sub-0.8 inch PWATs, suppressing cloud cover and keeping conditions
clear through Monday night.

On Tuesday, the thermal ridge axis will remain centered over the
Ohio Valley ahead of a cold front pushing southward out of the Upper
Great Lakes. Deep boundary layer mixing and ongoing southwesterly
flow will maintain unseasonable warmth with daytime highs again
reaching the upper 80s under mostly sunny skies with another shot at
breaking the record at IND. HREF and HRRR component members show
moisture transport increasing late Tuesday night along a pre-frontal
40 kt LLJ, raising PWAT values above 1.3 inches across northwestern
counties. Low-level convergence along the sagging surface boundary
will initiate scattered shower and elevated thunderstorm activity
after 06Z Wednesday, while areas further southeast remain dry
through the morning hours.

Wednesday Through Saturday.

The surface cold front will decelerate and align parallel to mid-
level southwesterly flow across central Indiana Wednesday and
Thursday. Ensemble guidance is hinting in a prolonged precipitation
event as multiple embedded shortwave impulses traverse the stalled
boundary. Strong low-level baroclinic forcing combined with moisture
advection drawing Gulf moisture northward will push PWATs above 1.5
inches along the frontal zone, exceeding the 90th percentile for mid-
October. Diagnostic soundings indicate elevated MUCAPE between 300-
800 J/kg and 0-6 km bulk shear around 40-50 kt, supporting embedded
thunderstorms and efficient rainfall rates along with a lower-end
threat for severe weather. Cloud cover, precipitation, and post-
frontal CAA north of the boundary will cap Wednesday and Thursday
highs in the upper 60s to mid 70s.

A robust upper-level trough will dig into the Eastern CONUS by
Thursday night, driving the frontal boundary south into the
Tennessee Valley and opening the path for strong CAA. High pressure
of Canadian origin will build across the Northern Plains into the
Great Lakes. Northwesterly winds will gust as high as 40 mph in the
aftermath of the frontal passage as strong pressure gradients remain
in place. These stronger winds will relax through the weekend as the
high centers over the Ohio Valley. Daytime temperatures will drop to
seasonable levels in the mid to upper 60s on Friday, cooling further
into the upper 50s and lower 60s on Saturday and Sunday. Clear
skies, light winds, and efficient radiational cooling over the
weekend will allow overnight lows to fall low to mid 30s with a
freeze possible across eastern Indiana and frost likely across all
of central Indiana.

&&

.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.

&&

$$

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