675
FXUS63 KIND 220659
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
259 AM EDT Tue Sep 22 2026

.KEY MESSAGES...

- Mainly cloudy and cool through Thursday

- Patchy drizzle or light rain showers tonight into Wednesday

- Dry and seasonable late week into the weekend with gradually
  warming temperatures

&&

.DISCUSSION (Today through Monday)...
Issued at 259 AM EDT Tue Sep 22 2026

Strong surface high pressure currently resides over southeastern
Canada, providing brisk northeasterly flow to Indiana. Low stratus
has been gradually expanding beneath a strengthening inversion. To
the west, an upper-level low over Iowa is slowly moving
southeastward.

Today

Northeasterly flow and overcast skies are expected to prevail today
as the synoptic setup described above remains in place. Wind speeds
may increase a bit to 10-15kt this afternoon, but should generally
remain around 10kt for the majority of the day into tonight.
Temperatures will be muted by the persistent cloud cover, with highs
in the upper 60s to near 70 anticipated.

Tonight into Wednesday

The upper-level low arrives late tonight which induces broad
cyclonic curvature in the surface wind field. Combined with
steepening lapse rates aloft, this should generate broad lift. The
added lift will have two main effects. First, the stratus deck that
is currently in place will thicken and lower, potentially to under
1000ft agl. Second, patchy drizzle or light rain showers may develop
after 00z this evening, continuing into Wednesday. Best chance of
drizzle/rain showers is over the northeastern half of our CWA.
Brief periods of reduced visibility are possible.

Similar to today, temperatures are expected to be reduced by the
cloud cover. Another day with highs in the upper 60s to near 70 is
likely. Lows tonight and Wednesday night should be in the 50s to
near 60.

Thursday through Sunday

The aforementioned upper low will settle over the Mid Atlantic
region during the second half of the week. Cool E/NE flow and at
least some lingering cloud cover on the back side of the developing
cutoff low will maintain below normal temperatures Thursday with
highs ranging from the upper 60s to the mid 70s from northeast to
southwest. Ridging aloft will gradually shift into the Ohio Valley
with an axis of deepening subsidence advecting into the region from
the north. Under mainly clear skies...temperatures will recover back
to late September normals with highs warming into the mid and upper
70s by Sunday and perhaps into the lower 80s over parts of the
forecast area by Monday. The coolest night since the Spring comes
Friday night as lows in the mid and upper 40s will be common...with
temperatures recovering into the 50s for lows by the end of the
weekend.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 154 AM EDT Tue Sep 22 2026

Impacts:

- MVFR ceilings persist, IFR possible this evening into Wednesday.
- Patchy drizzle this evening into Wednesday, isolated showers
  possible.

Discussion:

Strong surface high pressure resides over southeastern Canada,
providing a steady northeasterly breeze across central Indiana.
Winds have been between 10-15kt from LAF to IND, and 5-10kt from HUF
to BMG. Little change in winds speed is anticipated through the TAF
period, with only the prevailing direction becoming more
northeasterly with time.

Periodic MVFR ceilings are occurring across the region as well, with
coverage gradually expanding. We currently expect that stratus will
expand until it becomes an OVC layer this morning. Ceilings between
1500-2500ft are expected through this afternoon, lowering this
evening into Wednesday.

An upper-level low is expected to arrive tonight. This should induce
broad cyclonic curvature in the surface wind field, allowing cloud
cover to thicken and lower. IFR ceilings are possible after 00z,
becoming likely after 06z. Additionally, subtle lift may allow for
some patchy drizzle to develop overnight into Wednesday morning.
This may reduce visibility at times. A few rain showers cannot be
ruled out either.


&&

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

$$

AVIATION...Eckhoff
DISCUSSION...Ryan/Eckhoff