376
FXUS63 KIND 032320
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
720 PM EDT Thu Sep 3 2026

.KEY MESSAGES...

- Heat Advisory in effect for all of central Indiana through late
  Friday with peak afternoon heat index values up to 108 degrees

- Isolated to scattered thunderstorms will be possible at times
  Friday and Saturday

&&

.DISCUSSION (This evening through Thursday)...
Issued at 252 PM EDT Thu Sep 3 2026

Ridging will continue today across central Indiana, but a shortwave
will develop on the periphery and push just to the north and east. A
weak outflow boundary is currently draped across NE IL and NW IN,
but latest observations are showing this boundary becoming more
diffuse as it progresses eastward. This trend is expected to
continue with minimal impacts over central Indiana outside of a
slight increase in diurnal cumulus.

Most CAMs depict additional convective development later this
afternoon over northern IN where the shortwave is located, with a
general progression E/NE during the evening. While parameter spacing
does not support convective development over central Indiana, cold
pool development may allow for decaying thunderstorms or light
showers to reach northern central Indiana between 7-10PM.
Temperatures and heat index values will be high once again today.
There is some signs of mixing this afternoon which may drop dew
points a few degrees. A few occasional gusts to 18kt will also be
possible as the PBL becomes mixed this afternoon.

Conditions are expected to be very similar tomorrow, with a near
identical synoptic setup. The main difference is the position of a
mid level boundary and additional moisture convergence through the
850-700mb layer. This may allow for enough saturation in this layer
for isolated convective showers and thunderstorms in the late
afternoon and evening. While severe weather is not expected, DCAPE
of 900-1000 J/KG may support a few downbursts within this "popcorn"
convection to approach severe criteria. Where this mid level
boundary situates tomorrow will also be the primary location for
additional MCS development tomorrow afternoon through Saturday
morning. This is currently expected to remain NE of central Indiana,
but the area of concern will be close enough to where a brief
glancing from organized thunderstorms will be possible over far NE
portions of the area.

The mid level boundary will have more synoptic support Saturday,
with continental polar air attempting to move into the area from the
NE late Saturday into Saturday night. This should generally increase
convective activity across the area though moisture convergence and
increased wind shear. Confidence on where greatest thunderstorm
coverage will be located is low at this time.

A brief cooldown is likely Sunday through Monday as a deepening
trough over the East Coast, pushes the ridge westward. High pressure
is expected to build beneath upper level confluence leading to a
drying trend with highs in the mid 80s with dew points in the upper
50s to mid 60s. Towards the middle of next week, the ridge is
expected to build back over the region, with an additional stretch
of well above normal temperatures and humidity.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 720 PM EDT Thu Sep 3 2026

Impacts:

- Isolated convection possible Friday PM, especially near KIND/KLAF

Discussion:

VFR conditions are expected through at least 18Z Friday near central
Indiana terminals...with the same fair conditions continuing.
Hot and humid subtropical ridge will shift its center from the SE
CONUS to the Plains which will allow a small northern disturbance to
possibly drag isolated convection across the region late in the TAF
period.  So far confidence too low in TSRA for any mention in TAFs
past VCSH.

Otherwise, diurnal cumulus will dissipate through the start of the
period with passing mid/high cloud, especially over KLAF.  Minor VIS
reductions from patchy fog are possible late tonight...but certainty
in MVFR too low to include in TAFs.  Overall light winds tonight may
maintain subtle organized southerly flow to at least 06Z.  Winds
Friday afternoon outside of any convection will be from 240-280
degrees, nearing 7KT/10KT thresholds...with most gusts weaker than
prior days.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT Friday for INZ021-028>031-035>049-
051>057-060>065-067>072.

&&

$$

AVIATION...AGM
DISCUSSION...Updike