870
FXUS63 KIND 300638
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
238 AM EDT Thu Jul 30 2026

.KEY MESSAGES...

- Quiet weather with near normal temperatures today and tonight

- Showers and thunderstorms return late on Friday and continue through
  the weekend. There is an excessive rainfall threat Friday night
  through Saturday for most of central Indiana.

- Warming trend likely for the first week of August

&&

.DISCUSSION (Today through Wednesday)...
Issued at 237 AM EDT Thu Jul 30 2026

High pressure remains the predominant feature for today and
tonight as confluence aloft continues to build pressure through the
lower troposphere. The center of this surface high is expected to
track just to the north of central Indiana of which should lead to a
light easterly winds throughout the day. Low level cloud cover
should be fairly minimal throughout the day due to the ongoing
subsidence, but a few diurnal cumulus may be possible as upward
latent heat fluxes help provide some moisture to the PBL. Aloft,
moisture within an upstream mid level trough feature will likely be
kicked into the jet stream, with scattered cirrus clouds expected
over central Indiana by mid afternoon.

850mb temperatures will be the same today as yesterday, with
surface temperatures expected to respond accordingly; given the
slightly drier near surface air, afternoon highs will likely push
a bit higher with the current expected highs between 84-86F. The
only hazard of concern for today and tonight will be some
potential for fog development near the pressure center over N/NW
portions of the area. A majority of the fog should be contained to
low lying valleys and well irregated farmland, but this may
advect elsewhere depending on depth of any fog layer.

As mentioned, a mid level trough feature will continue to develop
throughout the day, mostly due to ongoing super-geostrophic flow
over the Rockies aiding in pressure falls over the western Missouri
Valley. Due to the placement of the jet, much of the pressure
depletion will be due to very strong diffluence and thus weak
steering flow with a majority of the ensemble members showing the
mid level low becoming detached from the flow aloft. The initial
rain threat is expected to be Friday late afternoon into the evening
along an elongated confluence band as the low pushes eastward. Any
rain on Friday afternoon and evening should be mostly light, but a
few elevated convective cells will be possible leading to a larger
range in QPF outcomes.

For Friday night through Saturday, forecast confidence starts to
wane. While ensemble members agree on the overall pattern, the path
and the strength of the cutoff low have varied some over the last
few runs due to the lack of strong dynamics. Latest trends have
shifted the center of the flow further north, nearing southern
portions of the area on Saturday. Due to the weak steering flow but
abundant upward lift near the cutoff low, near stationary and
training convection may be possible at times Friday night through
Saturday leading to an excessive rainfall threat over most of the
area. While an isolated damaging wind gust cannot be ruled out
throughout this event, weak low level lapse rates and bulk shear
will limit the severity of most thunderstorm. The best chance for
any severe wind gusts will be on the east to southeast side of the
low where the LLJ is a bit stronger, helping create bulk shear
values closer to 30kt.

For next week, there are not any strong signals within the 300mb
pattern leading to fairly high uncertainty on precipitation.
However, regarding temperatures, the polar jet looks to be well
displaced to the north, with should allow for above average 850mb
temperatures and therefor some likelihood of above average surface
temperatures.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1234 AM EDT Thu Jul 30 2026

Impacts:

- Patchy fog at KLAF early this morning

Discussion:

Mostly clear skies and lighter winds are expected overnight. This
may lead to some patchy fog development. MVFR or less VIS is most
favorable at KLAF and has been included within the issuance. Fog
cannot be ruled out at KHUF/KBMG, but for now feel odds are too
low to mention.

Any fog will mix out by around 12Z Thursday, with more scattered
diurnal cumulus developing.


&&

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

$$

AVIATION...Updike
DISCUSSION...Updike