354
FXUS63 KIWX 140641
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
241 AM EDT Mon Jul 14 2025

.KEY MESSAGES...

- Some smoke aloft from Canadian wildfires is expected to spread across
  the region today and into Monday, particularly across the
  upper Great Lakes.

 - Scattered showers and storms this afternoon and evening,
   especially south of US 24.

- A brief reprieve from higher humidity today into Monday but
  peak afternoon heat indices return into the 90s for Tuesday
  and Wednesday.

- Next chances for rain/storms arrive midweek, especially Wednesday
  and Thursday in the afternoon and evening.

&&

.UPDATE...
Issued at 1027 PM EDT Sun Jul 13 2025

Area of light rain will continue east over the next couple of
hours. Some CAMs linger it somewhat overnight, but think it will
be progressive. Some lower vsbys are showing up in areas where
the rain fell, suggesting at least some patchy fog could become
an issue overnight, especially if skies clear out. Have added
some patchy fog as a result.

&&

.DISCUSSION...
Issued at 224 PM EDT Sun Jul 13 2025

The cold front that moved through yesterday has slowed and is
currently draped from Toledo, OH southeast to just north of the
St Louis metro. There is a low level theta-e gradient across
the area today, with the best temperature and moisture found
along and south of the US 24 corridor. This area is also where
dewpoints are in the upper 60s to low 70s. As the front moves
through the rest of our forecast area this afternoon/evening,
scattered showers and a few isolated storms should develop
across north central Indiana. Much like the set up yesterday,
there is some instability for storms to tap into but shear is
very low so storms will remain sub-severe. Lightning, briefly
heavy rain, and gusty winds to 30-40 mph will all be potential
hazards along and south of US 24. Showers will gradually taper
off into the overnight hours.

Tonight, skies will clear out behind the front and winds will be
light and variable. Patchy fog will be possible, especially in areas
where showers and storms have moved through over the past 24 hours.
Leftover moisture near the surface should help allow for radiation
fog to form along and south of US 24 by early Monday morning.

In addition, wildfire smoke from Canada continues to drift into
across the Upper Great Lakes region. The greatest impacts to
air quality are expected across the UP and Northern Lower
Michigan, however, the statewide Michigan Air Quality Alert has
been expanded through the day Monday. It is possible that smoke
aloft gets as far as northern Indiana and far northwest Ohio,
making for hazy skies. Surface air quality should not be
impacted.

Heat and humidity will increase over the next few days,
especially on Tuesday. Southerly low level flow and WAA will
usher in low to mid 70s dewpoints on Tuesday and Wednesday, with
a notable increase in humidity. Highs will be in the upper 80s
to low 90s, with peak heat indices in the 90s. Mid range model
guidance has been persistent with an active pattern reemerging
by midweek. A 500mb shortwave will aid in thunderstorm
development as it pivots through the area Wednesday
afternoon/evening. Additional shortwaves pivot through Thursday
and a cold front sweeps through, with additional showers and
storms possible. Our typical summertime pattern of high
instability and minimal shear looks to set up once again, so it
is too far out to determine whether there will be any severe
potential with these storms. By the weekend, dry conditions
return with zonal flow over the Upper Great Lakes.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 214 AM EDT Mon Jul 14 2025

A weak front extended from about OKK to FWA to DFI. Fog was
forming behind the front and was becoming dense in spots. Have
left fog out of the terminals for now, but will continue to
monitor for possible inclusion the rest of the night. As for
thunderstorms, the activity has moved south and southeast out of
the area for now. Mid level lapse rate continue to be very
stable. A relatively small area of dry air has spread across
northern Indiana and should help keep storms from forming today.
Otherwise, winds should remain light.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Dense Fog Advisory until 9 AM EDT this morning for INZ013-015-
     020-022.
OH...None.
MI...Air Quality Alert until midnight EDT tonight for MIZ078>081-
     177-277.
MARINE...None.

&&

$$

UPDATE...Fisher
DISCUSSION...Johnson
AVIATION...Skipper