087
FXUS63 KLOT 040504
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1104 PM CST Wed Dec 3 2025

.KEY MESSAGES...

- Brief bout of very cold temperatures through Thursday night.

&&

.DISCUSSION...
Issued at 133 PM CST Wed Dec 3 2025

Through Friday Night:

Cold front is moving into our northwestern CWA early this
afternoon with areas of light snow and flurries ahead of the
front along with some transient bands of beefier snow with
larger snowflakes at times. This snow should end as cold front
moves through, with some guidance continuing to suggest there`ll
be a loss of ice nuclei and potential for some DZ/FZDZ southern
CWA early this evening.

In the wake of the front, low level cold air advection will send
temps tumbling tonight. As the column cools, cloud temps within
the lingering post frontal stratocumulus will drop as well,
dipping solidly into the range of ice being present. Pretty
common in these situations to get some very light snow or
flurries to leak out of these cold air stratocumulus clouds.
Have introduced some flurries into the grids tonight behind the
front.

Low temperatures tonight may not occur until a couple of hours
past sunrise Thursday as robust cold air advection likely
continues a slow temp fall beyond sunrise. Gusty northwest winds
will push wind chills below zero late tonight and Thursday
morning. Despite plenty of sunshine, Thursday will be very cold
with highs struggling to reach 10 above across interior northern
IL with highs into the teens in the urban heat island area of
Chicago metro and downwind of Lake Michigan across extreme
northwest Indiana. Diminishing winds Thursday afternoon will
allow wind chills to rebound to above zero during the Day
Thursday.

By early Thursday evening, guidance is in good agreement in
placing a 1028-1029mb high smack dab over northern Illinois.
Given the deep snowpack in place and clear skies, it is likely
that temps will quickly tank after the sun sets, particularly at
the typically colder locations. Wouldn`t be surprising to see
some of the typically cold spots drop to 5 to 10 below Thursday
evening, but with nearly calm winds, wind chills shouldn`t be a
factor. High pressure is progged to move east of the area
through the night Thursday, allowing southerly winds to develop
and gradually increase. The strengthening southerly flow will
send temps rising overnight, though the rise in temps will be
be partially offset by the increasing winds keeping wind chills
quite chilly.

- Izzi

Saturday through Wednesday:

There continues to be high uncertainty for precip chances in
the extended with some mention of blended chance pops from
Saturday night through the middle of next week. The one trend
that appears to be emerging is there could be a clipper parade
next week, with the potential that one or more of these pass
north of the local area, which would potentially allow temps to
moderate some. If there is precip falling with what will likely
be cold ground, some mixed precip would be possible, but way
too much uncertainty from this distance. cms

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 1104 PM CST Wed Dec 3 2025

In the wake of an arctic cold front that crossed the area early
last evening, NW winds gusting to around 20 knots will
gradually diminish through the morning. Winds will then back SW
under 10 knots mid afternoon as a surface high pressure shifts
across northern Illinois. SW winds are then expected to persist
through tonight. VFR conditions are favored through the period,
though clear skies (at least initially) Thursday night and weak
low-level warm air/moisture advection may result in developing
BR/MIFG.

Kluber

&&

.CLIMATE...
Issued at 542 PM CST Tue Dec 2 2025

Updated at 250 PM CST Tue Dec 2 2025

Here are the current record low temperatures for Thursday into
Friday this week:

Chicago           Cold High       Low
Thursday 12/4     13 (1991)      0 (1893)
Friday 12/5                      4 (2005)

Rockford          Cold High       Low
Thursday 12/4      7 (1991)     -4 (1991)
Friday 12/5                     -5 (2005)

- Izzi

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 9 AM CST Thursday for Winthrop
     Harbor IL to Gary IN.

     Small Craft Advisory until 3 PM CST Thursday for Gary to Burns
     Harbor IN-Burns Harbor to Michigan City IN.

&&

$$

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