912
FXUS63 KIWX 021917 CCA
AFDIWX

Area Forecast Discussion...CORRECTION
National Weather Service Northern Indiana
317 PM EDT Wed Jul 2 2025

.KEY MESSAGES...

- Slight chance (10-20%) for a stray shower or storm Thursday
  afternoon.

- Hot and humid Friday into this weekend.

- More appreciable rain and storm chances (40-50%) return Sunday
  into Monday.

&&

.DISCUSSION...
Issued at 245 PM EDT Wed Jul 2 2025

A mid level impulse tracking east-southeast through the central
Great Lakes will force a subtle (lake breeze enhanced) sfc trough
into areas mainly along/north of US 30 late this afternoon into this
evening. This feature may be enough to generate a stray shower or
two as cooling aloft potentially breaks cap in place, but nothing
more given the weak forcing and overall dearth of moisture and
instability.

Thursday will feature slight warmer conditions as heights rebound
aloft in wake of this evening`s shortwave. Boundary layer
moisture/instability will also see a bit of an uptick near a
boundary leftover across the Upper Midwest southeast into the lower
Great Lakes. An isolated shower or storm could focus near this
boundary and/or lake breeze during peak heating with PoPs limited in
the 10-20% range given an overall lack of flow/shear/forcing, along
with a tendency for dewpoints to mix out more than modeled for
lesser MLCAPE magnitudes locally.

A warmer, more humid air mass does become better established into
Friday and Saturday as an Intermountain West upper ridge folds east
into the Great Lakes and Ohio Valley. Friday is the transition day
with high temps and PM heat indices dependent on any lingering
convective cloud debris or outflow on the leading edge of the capped
heat dome. Continued to cap PoPs at 10% (silent) with NBM`s highs
near 90 reasonable for now. Higher confidence in Saturday being the
warmest day with PM heat indices in the mid 90s to near 100F under a
mostly sunny sky as low levels moisten within increasing southwest
flow.

Guidance does continue to flatten the ridge into Sunday and Monday
allowing an frontal boundary to drop into the vicinity with
chances for scattered convection.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 122 PM EDT Wed Jul 2 2025

As a shortwave moves through in the flow, increased moist advection
allows low to mid level cloudiness, but ceilings appear to be
high enough to keep VFR conditions prevailing. Southwest winds
continue to stay below 10 kts through the period.

&&

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

&&

$$

DISCUSSION...Steinwedel
AVIATION...Roller