007
FXUS63 KLOT 252033
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
233 PM CST Tue Nov 25 2025

.KEY MESSAGES...

- Strong westerly winds (gusts in excess of 50 mph) and much
  colder temperatures will define Wednesday. A few showers will
  occur north of Interstate 80, as well.

- Blustery and cold weather will continue through the evening
  hours on Thanksgiving Day.

- Impactful snow may occur this weekend, focused on Saturday.
  It`s still too early to get into the details.

&&

.DISCUSSION...
Issued at 233 PM CST Tue Nov 25 2025

Through Wednesday:

Conditions were slow to improve from the gloominess of this
morning, but visibilities have since recovered and now we remain
beneath a low-hanging stratus deck as we move through the
afternoon. The low stratus kept temperatures on the cooler side
today and now we`re seeing lower 50s around the area.

Zooming out of the local area, we find a low pressure
circulation over the eastern Dakotas and cold front moving
across Iowa and extending southwest into the Plains. A line of
light showers has developed along the front in recent hours and
is moving across central IA as of this writing. These features
will continue to progress eastward as the associated upper
trough digs into the upper Midwest this evening. The line of
showers is expected to approach the I-39 corridor early this
evening and work across the CWA through the end of the evening.
A few isolated showers may try and pop up ahead of this main
line, but they would be very light and isolated. Coverage of
showers should be pretty tightly confined to the front itself
and should only reside over any given area for an hour or two.
Chances are also highest across the northern CWA, where drier
air may keep southern portions of the area dry.

No precip is expected immediately behind the front and through
most of the overnight with a sharp cutoff in forcing and deeper
moisture. However, a secondary frontal feature/baroclinic zone
will swing across late tonight and reinvigorate some of those
ingredients in its wake and boost precip chances again for very
late tonight into tomorrow. Light precip, likely light rain,
should move into our northwest during the predawn hours behind
that secondary front and spread eastward. As we move closer to
daybreak, rain should mix with snow for a brief period before a
transition to all snow is expected around or shortly after
sunrise. Periods of flurries and snow showers are then expected
to persist through the afternoon. Coverage of any meaningful
snow should be confined to areas near and especially north of
I-80 with deeper moisture and better forcing nearer to low
track, while flurries may materialize farther south. There is a
possibility that we see some localized bands of moderate
snowfall at times amid the steep low level lapse rates and
strong shearing, although this does not appear to be a
widespread concern. Best chance of this will also be north of
I-80. Dustings to a couple of tenths of an inch are possible on
cooler and elevated surfaces, including bridges and overpasses,
but roads are expected to largely remain clear otherwise.
However, can`t entirely rule out a slick stretch following any
heavier push of snow, mainly on less-busy roads. The falling
snow in combination with strong winds (more on that below) may
make for messy travel at times during the morning and afternoon
commutes tomorrow. The column begins to dry out toward the end
of the afternoon which will put an end to precip chances.

Focus is also on strong to potentially damaging winds expected
in the wake of this evening`s front. Following the passage of
the front, cold advection will allow for efficient BL mixing
into 30+ kt of low level flow. After daybreak, an uptick in the
surface isallobaric component and low level wind field will
result in regular 45 to 50+ mph gusts out of the west through
the morning and afternoon. A few damaging gusts to near 60 mph
will be possible. The strongest winds are generally expected
across the northern CWA, but conditions look pretty similar
area-wide. Be sure to secure any outdoor furniture and
decorations before tomorrow. Also prepare for your vehicle to be
pushed around a bit by the wind tomorrow, especially when
traveling on open north-south roads. No changes were made to the
Wind Advisory which goes into effect for the entire CWA at 3AM
tonight and lasts into tomorrow evening. Gusts will ease during
the evening, but stay up to near 25 to 30 mph through the night
with another windy day in store for Thanksgiving.

Lastly, the cold advection and windy conditions will make for a
noticeably cooler day tomorrow. Behind this cold front, 850mb
temperatures are progged to drop about 25F between this evening
and tomorrow evening. Surface temperatures will stay up near 50
ahead of the frontal passage, then steadily drop through the
night bottoming out in the lower and middle 30s by tomorrow
morning. Continued strong cold advection will keep temperatures
nearly still from there. In fact, latest high-res guidance
suggests we may start to cool a little earlier than usual
tomorrow, early in the afternoon. The strong winds will keep
wind chills in the teens and lower 20s during the day.

Doom


Wednesday Night through Tuesday:

Wednesday night and into Thanksgiving day, the surface low
pressure system responsible for powerful winds across the Great
Lakes region will lift northeastward into southern Quebec. A
1030 mb surface high pressure system building in the central
plains will maintain a strong pressure gradient across the Great
Lakes in the wake of the surface low, facilitating blustery
northwest wind gusts of 30 to locally 40 mph throughout the day.
As a result, Thanksgiving day is shaping up to be pretty
chilly. Wind chills in the morning will be in the lower teens,
and only "recover" to the mid 20s by mid-afternoon even as
actual air temperatures rise toward the freezing mark. From both
the actual and "feels like" temperature, Thanksgiving 2025 is
shaping up to be the coldest in Chicago since 2014 when the high
temperature was 27. (Rockford logged a high temperature of 29
on Thanksgiving day last year).

Thursday night into Friday, the surface high pressure system
will shift eastward over the Mississippi River Valley leading to
a calm and chilly night. Overnight lows will range from the mid
teens in outlying areas to the mid 20s lakeside. While highs on
Friday will be similar to Thanksgiving day, the lack of wind
will make it feel quite a bit warmer.

Attention then turns toward the next storm system due to arrive
in our region this weekend. Ensemble model guidance remains in
agreement that an upper-level wave currently halfway between the
states of Hawaii and Washington will come ashore and propagate
eastward across the contiguous US on Friday and into the
Mississippi River Valley on Saturday. As the wave approaches, it
may attempt to phase with subtle preceding shortwaves emanating
from the remnants of the subtropical jet along the US/Mexico
border and a polar wave dropping south out of Canada. The degree
of interaction with any of these waves will ultimately
influence the eventual evolution of the storm system, which is
leading to the usual spread of ensemble outcomes typical for a
system 4 days out.

Generally speaking, the expectation is for a region of warm-
air advection snow to develop across the region early Saturday
morning and then to transition to "cold conveyer belt"
frontogenesis-driven snow Saturday into Saturday night.
Depending on the exact evolution and strength of the system, a
warm nose may surge into parts of the area leading to a
transition from snow to rain at some point on Saturday.
Regardless, the ensemble signal, particularly among the EPS
suite, remains strong for our general region to experience
impactful snow on Saturday. At this point, the message for this
weekend remains the same: Staying up to date on the forecast
especially if planning to travel in the general region.

Borchardt

&&

.AVIATION /18Z TAFS THROUGH 00Z THURSDAY/...
Issued at 1136 AM CST Tue Nov 25 2025

Key Aviation Messages for the current TAF period:

- Continued IFR conditions gradually lifting to MVFR late this
  afternoon.

- A cold front will pass over the region providing another
  chance for rain showers approaching and just after midnight.

- Wednesday will be a very windy day with gusts exceeding 40
  knots for much of the day.

- Flurries and snow showers are expected behind the front after
  day break with a chance for periods of stronger showers that
  may reduce vis down to IFR conditions.

The rain and drizzle has stopped, but IFR cigs and vis between
6-10 miles remains around the region. Cigs will continue to
gradually lift to MVFR levels late this afternoon. MVFR
conditions are expected to remain through the end of the TAF
period.

As a center of low pressure deepens over northern Wisconsin
tonight, it will send a cold front over northern Illinois and
Indiana overnight. Localized wind gusts around 20 knots and rain
showers are expected along the front as it passes. Behind the
front, the pressure gradient will tighten and increase wind
gusts. Gusts over 30 knots are expected after midnight and will
only increase after daybreak. There is increasing confidence for
wind gusts over 40 knots on Wednesday, but it would not be
surprising if there were occasional obs to 50 knots especially
for locations closer to Wisconsin and the lake.

Temperatures will quickly drop behind the front. While there
will be a break in precip after the rain showers, light
snow/flurries are expected are expected after daybreak (slightly
earlier for areas closer to KRFD). However, stronger snow
showers may have the ability to drop vis down to IFR conditions.
Flurries may linger into the afternoon, but will gradually
diminish as the low finally moves farther north and east. Cigs
will gradually lift toward VFR and wind gusts are expected to
diminish down to 30 to 40 knots toward 00Z.

DK

&&

.MARINE...
Issued at 233 PM CST Tue Nov 25 2025

Key Marine Messages include:

- A Gale Warning is in effect tonight through Thursday for the
  Illinois and Indiana nearshore waters of Lake Michigan.

- Peak wind gusts of 45 to 50 kt are expected on Wednesday,
  tapering to 35 to 40 kt on Thursday.

A powerful cold front tied to a approaching low pressure system
will sweep across the area tonight. Westerly winds will
increase markedly behind the cold front to gale force tonight,
and increase further to nearly storm force Wednesday afternoon.
Peak wind gusts of 45 to 50 kt are expected in the Illinois and
Indiana nearshore waters of Lake Michigan on Wednesday, with
higher wind gusts at high platform observation stations and
over the open waters of Lake Michigan. While the magnitude of
winds will gradually ease from Wednesday night onward, they
will remain at or above gale force (35 to 40 kt) all the way
through Thursday evening.

A Gale Warning is in effect for the Illinois and Indiana
shorelines of Lake Michigan tonight through Thursday. A Storm
Warning is in effect for the open waters of Lake Michigan on
Wednesday before transitioning to a Gale Warning on Thursday.

Borchardt

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Wind Advisory from 3 AM to 9 PM CST Wednesday for ILZ003-
     ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-
     ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039-ILZ103-
     ILZ104-ILZ105-ILZ106-ILZ107-ILZ108.

IN...Wind Advisory from 3 AM CST /4 AM EST/ to 9 PM CST /10 PM EST/
     Wednesday for INZ001-INZ002-INZ010-INZ011-INZ019.

LM...Gale Warning from 3 AM Wednesday to 10 PM CST Thursday for the
     IL and IN nearshore waters.

&&

$$

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