692
FXUS63 KIWX 220517
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
117 AM EDT Fri Aug 22 2025

.KEY MESSAGES...

- Fog expected early this morning.

- There is a low chance (10-30%) for showers Saturday afternoon.

- Significant cooldown Sunday through the middle of next week.

- Dangerous swimming conditions for southeast Lake Michigan beaches
  possible Sunday into Monday.

&&

.DISCUSSION...
Issued at 224 PM EDT Thu Aug 21 2025

Quiet, seasonable weather will persist through at least Friday night
as the center of high pressure drifts southward into the region.
Northeast winds will diminish as a result with a period of optimal
radiation cooling tonight potentially allowing low stratus and/or
fog to develop, best chances for fog along/north of US 24 toward
daybreak. Any fog or stratus likely lifts by mid-late morning,
leaving a mainly sunny and pleasant Friday afternoon with highs near
80F.

A low pressure system tracking east through the Canadian Prairies and
toward James Bay will drive a cold front through the local area
Saturday afternoon into Saturday evening, with available guidance
still differing in exact timing of the fropa. There is agreement
however on lacking convergence and moisture on the front, with the
pre-frontal environment likely capped as well. Point chances for a
shower or storm along the front str on the low side (10-30%) as a
result.

A touch of some fall-like weather remains a consistent theme in
ensemble and deterministic model solutions Sunday through the middle
of next week as single digit 850 mb air advects in. This will occur
as several shortwaves track through in northwest flow providing non-
zero chances for a few showers, mainly diurnally driven, and
additional surges of cooler air. The lake will also activate in this
regime hinting at better rain chances closer to Lake MI at
times.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 112 AM EDT Fri Aug 22 2025

Existing TAFs were overall on track, resulting in just a couple
modest changes. Observations indicate patchy, rather transient
fog is in the area. Some sites have been as low as about 1/2
mile. Most sites in northern IN and southern MI area reporting
about 2-3SM, only to return to P6SM. This decreases forecast
confidence only somewhat. High confidence on the favored window
of lowest visibility, which is in line with climatology.
Signals in forecast guidance continue to favor BR/FG at KSBN
this morning with a weaker signal at KFWA. High pressure
otherwise provides light wind today.

&&

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

&&

$$

DISCUSSION...Steinwedel
AVIATION...Brown