537
FXUS63 KIWX 242343
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
743 PM EDT Sun Aug 24 2025

.KEY MESSAGES...

- Cooler weather ahead with highs mid 60s to low 70s Mon-Tue.

- Scattered lake effect showers late this afternoon through Tuesday,
  best chances (20-50%) across far northern IN and lower MI.

- Mainly dry mid week through next weekend with highs generally in
  the mid-upper 70s, still below normal.

- There is a Beach Hazards Statement in effect through Tuesday
  evening for Lake Michigan beaches.

&&

.DISCUSSION...
Issued at 206 PM EDT Sun Aug 24 2025

Shortwave and associated secondary sfc trough will pivot through in
cyclonic wnw flow late this afternoon and evening with another shot
of CAA. Steepening lapse rates on the leading edge of the associated
cold pool aloft, and initial lake MI moisture fluxes as 850 delta
T`s push into the teens, will provide chances for lake enhanced
showers into mainly north-central IN and southwest MI, with a
transition to pure lake effect (iso-sct) overnight into early
Monday. Another mid level impulse then follows through on Monday
with diurnal heating of the boundary layer and maintenance of lake
moisture flux in cool northwest flow. Further inland penetration of
scattered showers into areas mainly along and north of US 30 is
expected on Monday as a result with light rainfall amounts
anticipated. Similar conditions then into Monday night and Tuesday
with the area remaining in cool and perturbed northwest flow. This
will keep chances for lake effect/enhanced showers around with highs
on Monday and Tuesday only reaching the mid 60s to near 70.

The second half of the week into next weekend will feature slight
air mass modification and mainly dry conditions as upper troughing
relaxes a bit with sfc high pressure in control for most of the
period. A trailing mid level trough and associated sfc boundary may
slip south through the area around Thursday. Moisture appears limited
however with NBM PoPs capped at 10-20%.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 743 PM EDT Sun Aug 24 2025

An upper low sits over south-central Canada and that continues to
send vorticity through the lower lobe of Lake MI through this taf
period. Given the slight above normal lean to the Lake MI temps and
the well below normal low level of the atmosphere temperature
anomalies, increased lake induced instability has allowed for
increased chances for showers, especially within the peak heating
times. Even still, better moisture arrives this evening behind a
vigorous vort max moving through and this is expected to initiate
lake induced showers that continue at times through the end of the
taf period. One such stronger vort max pinwheels through the area
midday into the afternoon and that should allow SBN to be removed
from shower chances by mid to late afternoon whereas FWA starts the
day dry but gets into the showers mid to late morning and finishes
the taf period with the shower chances. There could also be some
thunderstorms around during the peek heating period and, while 500
J/kg of MUCAPE may make it difficult for small hail and graupel,
cannot totally rule it out. As such, will add a prob30 group for FWA
with MVFR VIS reductions within potential thunderstorms, but there
is some question about thunderstorms too. Due to the good low level
lapse rates, another day of gusty winds is in store, but perhaps not
as strong with the weaker low level jet. Gusts to the low 20s of kts
will be possible at SBN, but weaker gusts will be possible so that
really only sustained winds around 10 kts will be maintained in the
FWA taf.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement through Tuesday evening for INZ103.
OH...None.
MI...Beach Hazards Statement through Tuesday evening for MIZ177-277.
MARINE...Small Craft Advisory until 8 PM EDT Tuesday for LMZ043-046.

&&

$$

DISCUSSION...Steinwedel
AVIATION...Roller