751
FXUS63 KLOT 122320
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
520 PM CST Wed Nov 12 2025

.KEY MESSAGES...

- Temperatures are expected to warm to well above normal
  readings for this time of year going into this weekend.

- While there is a low (15-20%) chance for light rain showers or
  sprinkles on Saturday, better chances for precipitation
  (40-60%) are expected to come during the first half of the
  upcoming workweek.

&&

.DISCUSSION...
Issued at 316 PM CST Wed Nov 12 2025

Surface ridging will promote continued dry conditions along
with moderating temperatures going into this weekend. This
warming trend may not begin until Friday in earnest, however, as
a greater degree of upper-level cloud cover and shallower
boundary layer mixing should prevent tomorrow`s high
temperatures from climbing much above today`s largely mid 50s
highs. Locations with a lingering snowpack from our recent lake
effect precipitation event should again lag behind in the
temperature department by a few degrees compared to areas
without a snowpack, though seeing how quickly the spatial
footprint of the snowpack has shrunk on GOES visible satellite
imagery today, this difference may not end up being all that
great if most of the remaining snow melts by tomorrow afternoon.

Modest warm air advection should be more discernible on Friday
as winds turn southerly on the backside of the surface ridge.
Friday`s highs look like they`ll largely end up in the 60s,
while rising dew points will raise the floor for Friday night`s
low temperatures, putting them more on par with the
climatological highs for this time of year (roughly at or around
50 degrees). Initially southwesterly winds on Saturday will
then turn breezier as a cold front approaches from the
northwest. The commensurately strengthening degree of warm air
advection may help push locations in our southern counties to
or above the 70 degree mark before the cold front passes
through during the afternoon or evening.

This cold front on Saturday will be accompanied by an upper-
level trough diving into the Great Lakes. The core of this
trough -- and the associated greater large-scale forcing for
ascent -- will track to our north and northeast, keeping the
bulk of its attendant precipitation away from our forecast area.
We may still yet receive enough of a glancing blow of ascent
for cloud depths here to grow deep enough to support
precipitation, though antecedent dry low- to mid-level air may
make it difficult for descending hydrometeors to reach ground
level. Thus, if any precipitation were to occur on Saturday, it
would likely come as a brief period of light rain or sprinkles.

Dry conditions and a return to cooler, more seasonable
temperatures are expected on Sunday in the wake of the frontal
passage, but our next chance for precipitation should come
during the first half of the upcoming workweek as upper-level
ridging over the central CONUS starts to break down somewhat and
at least one upper-level shortwave trough ejects from the
southwestern CONUS in our general direction. The ensemble
spread in this trough`s evolution unsurprisingly remains vast
this far out, so confidence in both the timing and the spatial
extent of any precipitation in our area remains quite low at
this point. The depth and integrity of mean troughing over the
northeastern quadrant of the CONUS (and thus how far
south/southwest the associated colder air mass will reach) may
play a key role in whether any wintry precipitation could
potentially come into play, but ensemble guidance also exhibits
a large spread with this, so there are still plenty of questions
that need to be resolved regarding the precipitation potential
for the first half of next week.

Ogorek

&&

.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...
Issued at 520 PM CST Wed Nov 12 2025

No significant aviation weather concerns for the 00Z TAFs.

Breezy west winds will diminish quickly with sunset early this
evening, and should remain 10 kts or less through the day
Thursday as an area of high pressure moves from the Plains to
the western Great Lakes region. Winds are expected to shift
southwest and eventually south-southwest late afternoon into
Thursday evening as the high pressure ridge axis moves across
and east f the terminals.

Patchy VFR high clouds are expected through the period.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 9 PM CST this evening for the IL
     nearshore waters.

     Small Craft Advisory until 3 AM CST Thursday for the IN
     nearshore waters.

&&

$$

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