434
FXUS63 KIWX 031027
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
627 AM EDT Thu Jul 3 2025

.KEY MESSAGES...

- Slight chance (15-20%) for a stray shower or storm this
  afternoon and evening.

- Hot and humid Friday into this weekend.

- Somewhat better chances for showers and storms (40-50%)
  return Sunday into Monday.

&&

.DISCUSSION...
Issued at 358 AM EDT Thu Jul 3 2025

The region will continue to be impacted by weak disturbances
into this evening with upper level heights slowly building
overnight into the start of the weekend. As noted this past
evening, a moderately unstable environment will be in place with
MLCAPE in the 1000 to 1500 J/KG range along with steep low level
lapse rates and inverted V soundings (DCAPE 900-1200 J/KG). A
lack of clear triggers will result in another day of very
isolated convective development that can form on any boundaries
(lake breeze or remnant outflows from evening convection) or
that move in from upstream. No more than slgt chc pops are
warranted at this point mainly in the 20 to 24Z time frame.
HRRR, which handled the evening scenario, does suggest some
convection could persist in SW areas through 3 or 4Z but for now
have not extended pops.

As noted, upper level ridging will expand northeast Fri into
Saturday with afternoon highs reaching their peak with highs
likely into the 90s. Some signals exist in a few models that
mixing of slightly lower dewpoints could occur each afternoon
that would subsequently limit impacts from heat indices, but
could also allow highs in some areas to overachieve. Have kept
status quo for now and defer to later shifts to watch trends.

The next trough will begin to edge in for Sunday and Monday
bringing somewhat better chances for showers and storms. Model
blends have backed off from likely pops as overall setup is
similar to earlier this week with what will probably be limited
coverage for the area and some seeing little rainfall.

Temperatures trend back down somewhat for next week with highs
back into the low to mid 80s and somewhat lower dewpoints with
the NW flow re-establishing as well as a series of weak
disturbances to bring periodic, diurnal chances for
showers/storms.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 626 AM EDT Thu Jul 3 2025

VFR conditions will prevail through this TAF period. Light and
mainly variable winds will become north-northwesterly during the
day. Diurnal cumulus also will develop aoa 5 kft during the
daytime. A low confidence for an isolated shower/thunderstorm
especially for KSBN after 18z, but have opted to leave out of
TAF forecast with the large uncertainty with the mainly pop-up
scenario in place.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Fisher
AVIATION...Andersen