336
FXUS63 KIWX 291832
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
232 PM EDT Sun Jun 29 2025

.KEY MESSAGES...

- Warmer and humid this afternoon with heat indices in the low to
  mid 90s.

- Rain/storms are possible Monday morning, then likely Monday afternoon
  and evening. A few storms could be strong to severe with
  damaging winds and heavy rainfall.

- Dry, seasonable, and less humid by mid to late in the week.

&&

.DISCUSSION...
Issued at 231 PM EDT Sun Jun 29 2025

A warm front has lifted northwest across the area today, which will
allow for highs in the mid to upper 80s this afternoon alongside a
noticeable increase in humidity. Southerly low-level flow has
helped to pull in moisture from the Gulf, which has brought
dewpoints up into the low 70s today. Heat indices are expected
to peak in the low to mid 90s this afternoon. A few isolated
showers/storms will be possible this afternoon and evening
across north-central Indiana, mainly south of US 24 and west of
US 31.

WAA continues into the day on Monday with highs in the 80s and
dewpoints in the low to mid 70s. An area of low pressure will lift
across the Midwest and it`s attendant cold front will bring high
chances (60-80%) for showers and storms. With the aforementioned
heat and humidity, this should allow for destabilization to
occur during the day Monday and for thunderstorms to develop.
The Storm Prediction Center has maintained the Marginal Risk
(level 1 of 5) for our entire forecast area, meaning a few
storms could be strong to severe. Overall, Monday looks fairly
unimpressive and disorganized for severe weather, especially
considering there may be some showers to deal with in the
morning. An initial round of scattered showers (not as much
confidence in thunderstorms) will be possible Monday morning as
a shortwave lifts out of the St Louis area. A second,
potentially stronger, round of storms will then be possible
Monday afternoon and evening with the cold front. Multicell
clusters/a broken line of thunderstorms should develop ahead of
the cold front and sweep through the area. These storms will
have modest instability (1500-3000 J/kg) to work with, however
lapse rates will be poor and there will be little to no shear in
place as vertical wind profiles are unidirectional out of the
southwest. Lingering showers and clouds in the morning and early
afternoon may also hinder severe chances. Confidence in severe
weather is low. If any storms do manage to reach severe
thresholds, the primary threat will be damaging winds. Locally
heavy rain is also possible with long, skinny CAPE profiles, a
deep warm cloud layer, and PWATs of 1.75-2" Monday afternoon and
evening.

July will start on a seasonable and dry note as surface high
pressure and an upper level ridge build in by midweek. Tuesday
through Friday currently looks to be mainly dry, with lower levels
of humidity and seasonable temperatures. Some diurnal chances for
rain/storms may be possible for the 4th of July and into the holiday
weekend depending on how amplified the upper level ridge is. For
now, have kept PoPs low at 20-30% at times through the weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 126 PM EDT Sun Jun 29 2025

A trough traverses the Northern Plains this afternoon into Monday
and allows a vort max to rise northward towards the area Monday
morning. A more humid air mass returns Monday morning and this
environment may make it more conducive to allowing for convective
cells that could produce lightning as early as the morning, more
likely for FWA than SBN, but not zero chances even for SBN.
Depending on instability and eventual shortwave position, the better
chances for showers and storms is Monday afternoon, but the
shortwave position could remove SBN from rain chances.

South wind today obtains a westerly component on Monday. While winds
stay weaker than 10 kts today, so 15 to 20 kts breezes will be
possible on Monday.

&&

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

&&

$$

DISCUSSION...Johnson
AVIATION...Roller