610
FXUS63 KLOT 231809
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1209 PM CST Sun Nov 23 2025

.KEY MESSAGES...

- Mild temperatures (highs in the 50s) are expected today.

- Widespread light rain (>80% chance) Monday night into early
  Tuesday.

- Turning cold and blustery Wednesday with wind gusts > 35 mph,
  potentially paired with a few flurries.

- Unseasonably cold temperatures (highs in the 30s) continue on
  Thanksgiving and through the end of the week.

&&

.DISCUSSION...
Issued at 314 AM CST Sun Nov 23 2025

Surface high pressure will foster a mostly sunny and dry day
across the region as it tracks eastward across the Mid-
Mississippi Valley today. With abundant sun, expect temperatures
to be a bit warmer than yesterday, with readings expected to
top out in the low to mid 50s. This relatively mild weather will
persist through Tuesday, albeit with a chance of light rain
Monday night into early Tuesday. Thereafter, a significant
weather pattern shift is expected to driver our area into a much
colder (winter-like) airmass for the later half of the week.

Low-level flow will turn south-southwesterly tonight into early
Monday following the eastward departure of the surface high,
and in response to the approaching impulse ejecting out of the
Desert Southwest today. As this occurs, low-level moisture will
surge northward into the area by early Monday morning, and this
adds concern for the development and expansion of a very low
stratus deck (IFR to LIFR) into our area for Monday. Current
conditions already indicate that low stratus and fog are ongoing
in the Ozarks, and several models (particularly the RAP, HRRR
and NAMnest) have this area expanding northward tonight. This
adds concerns for our temperature forecast for Monday. If we end
up with an expansive area of low stratus, temperatures on
Monday may remain nearly steady in the low to mid 40s. After
collaborating with neighboring offices we have opted to cut the
NBM forecast highs in the mid 50s by several degrees, going
closer to 50 for highs on Monday. Admittedly, however, these
readings may still be several degrees too warm.

While low-level cloud cover could be in our future for Monday,
it still appears that most of the daylight hours will remain
precipitation free. Light rain chances will then begin to ramp
up Monday night as deeper moisture arrives with the approaching
impulse shifting over the Mid-Mississippi Valley. Overall, this
period of rain does not look to amount to a whole lot, with most
areas likely to see less than a quarter inch before the light
rain tapers off Tuesday morning.

Following quickly on the heals of this system, another quick
moving northern stream impulse will quickly dig in across the
western Great Lakes Tuesday night into Wednesday. As it does,
surface low pressure will deepen and consolidate north of our
area over the Upper Great Lakes, with an associated strong east-
southeastward surging cold front expected to punch eastward
across the area Tuesday night. In the wake of this frontal
passage, strong cold air advection and rapid pressure rises will
drive increasingly strong gusty west-northwesterly winds
(possibly gusting in excess of 40 mph at times) late Tuesday
night into the day on Wednesday. While not much in the way of
precipitation is expected for Wednesday, some occasional
flurries or intermittent light snow showers may occur with any
lingering strato Cu. However, the primary weather story will be
the gusty winds with a quick turn towards a much colder,
winter-like airmass for the second half of the week, including
on Thanksgiving Day. Expect high temperatures to only be in the
low to middle 30s with wind chills in the teens and 20s.

Beyond Thanksgiving, signs continue to point to a turn towards
a much more active weather pattern across the central CONUS
this weekend going into the first week of December. Overall, the
larger scale pattern across North America continues to favor
upper troughing setting up across the western CONUS and upper
ridging across the southeastern CONUS during this period. The
presence of greatly enhanced southwesterly mid and upper level
flow into the lower Great Lakes in such a pattern is notorious for
steering numerous impulses across our region. Accordingly, some
periods of active weather, with rain and/or snow is possible as we
head into next weekend. It is important to note, however, that as
is typical, while the pattern looks increasingly active, the
finer scale details this far out remain largely unclear and will
need to be ironed out in the coming days. Nevertheless, this
period will be monitored closely for potentially impactful
weather systems across the central CONUS that could impact
holiday travel. Stay tuned.

KJB

&&

.AVIATION /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 1209 PM CST Sun Nov 23 2025

Key Messages:

- There is a potential for low ceilings and visibilities
  tomorrow, though there is high uncertainty in the occurrence
  and duration of any sub-VFR conditions.


There are no forecast concerns through the remainder of the
daytime hours today and most of tonight with VFR conditions
prevailing and winds largely remaining under 10 kts. There are
concerns for late tonight through tomorrow, however, as a plume
of low-level moisture lifts northward into the ZAU airspace.

Much like what was seen this morning across most of central and
southern Illinois and the Ozarks, this moisture plume will
likely feature an expansive blanket of IFR/LIFR stratus and fog
as it approaches the Chicago and Rockford metro areas tomorrow
morning. However, it remains uncertain whether this stratus and
fog will reach our TAF sites or whether it will remain just
south of the terminals. Forecast guidance remains split on which
scenario to favor, so did not have enough confidence to steer
the TAFs one way or another with respect to ceilings and
visibilities and have thus maintained a "middle ground"
approach in the 18Z TAFs.

The other point of forecast uncertainty is how long the
stratus/fog persists tomorrow if it does end up overspreading
the terminals late tonight/early tomorrow morning. Would again
think that things would play out similar to what happened to
our south today with the stratus and fog eroding by midday along
the periphery of the low-level moisture pool (where the stratus
deck is thinnest) and persisting through most or all of the day
elsewhere. Elected to advertise a more pessimistic scenario in
the TAFs with respect to the duration of the sub-VFR conditions,
but again, confidence that this will ultimately turn out to be
the case is still fairly low at this time.

Ogorek

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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