645
FXUS63 KIWX 292345
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
745 PM EDT Fri Aug 29 2025

.KEY MESSAGES...

- A slow moderation in temperatures expected through early next
  week with highs back near 80 degrees Monday and Tuesday.

- A few sprinkles or light rain showers are possible across
  northwest Indiana tonight, but otherwise dry weather expected
  through early next week.

- The next chance of showers and thunderstorms arrives by the
  middle of next week with a strong cold front. Much below
  normal temperatures are expected behind this cold front for
  next Thursday and Friday.

&&

.DISCUSSION...
Issued at 248 AM EDT Fri Aug 29 2025

A backdoor push of some better low level moisture earlier today has
transitioned to mainly an enhanced diurnal cu field.  This moisture
gradient will gradually drop southward through this evening, but low
level theta-e gradient will sharpen across the western Great Lakes
in response to a wave dropping southeast from the western Great
Lakes. Some increased in 900-800 mb moisture advection will precede
this wave, particularly across northwest Indiana. A large area of
showers is already accompanying this upstream forcing across
portions of central/southern Wisconsin. Some very weak elevated
instability may accompany this moisture advection, but especially
for areas to the west across NE Illinois/SE Wisconsin. Some
HREF support exists for a low end potential of measurable
precip across the far northwest in the 06Z-12Z timeframe, but
for now will just include chance sprinkle mention overnight.

Otherwise, increasing low/mid level moisture will result in
increasing clouds tonight, particularly across western
locations. This should result in warmer min temperatures for
areas west of Interstate 69 with a possibility that mins may not
drop below 50. Confidence is somewhat on the low side, but did
include patchy fog mention across the east where the increase in
clouds will at least be somewhat more delayed.

Chances of any light precip across the west should diminish early
Saturday morning as the northwest flow wave drops southeast. Passage
of this wave will keep broad low level thermal troughing anchored
across the southern Great Lakes, Highs should be a few degrees
warmer than today`s readings with slight modification of low level
airmass and better insolation expected Saturday afternoon.

No major changes to the previous forecast for the weekend into early
next week with an expansive low level ridge axis across the region.
The upper level wave pattern will stagnate this weekend into early
next week with upper low closing off across the Mid Atlantic and
a northern latitude upper ridge axis dropping southeast across
southern Ontario. As this ridge sinks southeast into Monday, low
level thermal profiles should continue to moderate through the
weekend with highs in upper 70s to around 80 expected for
Monday/Tuesday.

One feature that may need to be watched is an upper level short
wave dropping southeast across the Central Plans on Monday.
This short wave is expected to have a large wavelength that
could induce some sfc pressure falls across the Ohio Valley.
Some non-zero chance exists that some low level moisture could
advect into NE IN/NW OH in response to this feature late
Monday/Tuesday, but confidence remains much too low for PoPs at
this time.

Medium range guidance remains in fairly good agreement with a more
potent upper trough and associated strong cold frontal boundary
passage in the Wed-Thu timeframe. Some expected timing differences
still exist which will need to be refined in future forecasts. A
period of much below normal temperatures is expected behind this
cold front for next Thu/Fri.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 739 PM EDT Fri Aug 29 2025

VFR conditions are expected at the TAF sites, with primarily
light NW flow at KSBN and more easterly flow at KFWA. Both sites
should be variable this evening into the late morning.
Otherwise, a band of BKN ceilings around 12Kft will impact both
terminals through the evening and at least part of the
overnight, with KFWA seeing SCT-BKN ceilings around 5K (quite
variable from surrounding obs-most appear around 12Kft).
Sprinkles are possible at KSBN, but left out of TAF given no
impact.

&&

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

&&

$$

DISCUSSION...Marsili
AVIATION...MCD