838
FXUS63 KIND 070945
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
545 AM EDT Wed Oct 7 2026

.KEY MESSAGES...

- Warm and dry conditions persist through Friday with daily highs
  reaching into the mid 70s to low 80s

- Minimum RH values will drop below 30 percent at times through
  Friday bringing slightly elevated fire danger

- Tropical moisture surging northward will bring increasing chances
  for rainfall to central Indiana on Sunday

&&

.DISCUSSION (Today through Tuesday)...
Issued at 133 AM EDT Wed Oct 7 2026

Today Through Thursday.

Surface high pressure centered along the Mid-Atlantic coast and
broad mid-level ridging positioned over the eastern third of the
CONUS will maintain southwesterly low-level flow across the Ohio
Valley through Wednesday. Deep-layer subsidence and low column
moisture will keep skies mostly clear. Boundary-layer mixing under
full insolation will easily allow afternoon temperatures to warm
into the upper 70s, roughly 8 to 10 degrees above normal. HREF
ensemble member soundings show strong daytime momentum transfer
within the mixed layer, yielding southwesterly surface winds of 10
to 12 mph with occasional gusts up to 18 to 20 mph Wednesday
afternoon. This strong mixing will also help to bring lower
afternoon dewpoints with min RH values below 40 percent, and locally
lower than 30 percent with models often underdoing the afternoon
dewpoint drop in this pattern. Lows Wednesday night will drop into
the lower 50s under clear skies and light south-southwesterly flow.

On Thursday, a northern stream shortwave trough tracking across the
Upper Great Lakes will push a weak, moisture-starved surface trough
south across central Indiana. GFS and ECMWF soundings show a
persistent layer of dry air in the 850mb to 500mb layer, with
forcing for ascent remaining well north of the forecast area.
Consequently, the boundary will pass dry with PoPs held under 10%.
Winds will veer to the northwest around 10 mph behind the boundary.
Minor cold air advection will be largely offset by continued
insolation, keeping afternoon high temperatures more towards the
upper 70s. High pressure building in from the Upper Midwest Thursday
night will allow for efficient radiational cooling, dropping
overnight lows into the mid to upper 40s.

Friday Through Tuesday.

Surface high pressure translates eastward across the Great Lakes on
Friday, maintaining dry conditions and light east to southeast
surface flow across central Indiana. High temperatures will remain
mild in the mid 70s under mostly sunny skies, with overnight lows
Friday night slightly milder with stronger surface winds helping to
keep radiational cooling less efficient.

The primary focus of the extended period continues to be the
potential for tropical moisture impacts over the weekend. A mid-
level trough over the Central Plains is forecast to interact with
tropical moisture associated with Tropical Depression Nine moving
north out of the Gulf states. Ensemble and deterministic guidance
from the GFS, ECMWF, GEFS, and EPS display strong consensus in
developing a broad poleward moisture transport corridor streaming
northeastward into the Ohio Valley. Mid-level cloud cover will
increase through the day Saturday with high temperatures topping out
in the mid 70s. Strong isentropic ascent, coupled with upper-level
divergence in the right-rear quadrant of an accelerating jet streak
over the Great Lakes, will generate rain across the region beginning
late Saturday night through Sunday morning with the main uncertainty
being exactly where the tropical remnants will track. NBM and EPS
probabilities for 24-hour rainfall exceeding 0.50 inches remain in
the 60 to 70 percent range for central and southern portions of the
forecast area. Persistent cloudiness and precipitation will hold
daytime highs to the upper 60s on Sunday, with lows remaining
elevated in the upper 50s.

Rain will taper off late Sunday afternoon into Sunday night as the
tropical moisture plume shifts east toward the Appalachian region
and the primary trough axis translates east. Subtropical ridging and
a broad mid-level dry slot build back over the region on Monday,
leading to quick clearing and rebound warming. High temperatures on
Monday will climb back into the upper 70s to near 80 under return
southwesterly flow. By Tuesday, a secondary northern stream
shortwave and associated surface cold front will sweep through the
Midwest. Strong cold air advection behind the front will bring
cooler weather towards mid-week.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 545 AM EDT Wed Oct 7 2026

Impacts:

- Southwesterly wind gusts to 20kt from 16Z to 00Z

Discussion:

Outside of passing cirrus with a weak frontal passage this
afternoon, skies will be clear through the TAF period with the
primary aviation impact being southwesterly wind gusts this
afternoon. Gusts will generally be 15-20kt but there could be a few
gusts as high as 25kt at times. In the aftermath of the frontal
passage, winds will then shift more northwesterly, remaining at 5-
10kt through the overnight into Thursday.

&&

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

$$

AVIATION...White
DISCUSSION...White