373
FXUS63 KLOT 030809
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
209 AM CST Mon Nov 3 2025

.KEY MESSAGES...

- Seasonably mild, frequently breezy, and dry through midweek.

- Best chance for measurable rain this workweek will be late
  Thursday night into Friday morning.

- Turning sharply cooler next weekend.

&&

.DISCUSSION...
Issued at 209 AM CST Mon Nov 3 2025

A deep--nearly 980 mb--surface low is currently pushing across
the Hudson Bay with an attendant cold front set to shift across
the region later this morning. In advance of this front, a few
light showers/sprinkles will be possible as the cloud deck works
its way down to around 7-8 kft. With only modest CAA in the
wake of the front and a rapidly-drying column leading to full
sunshine, temperatures will rise to around 60 degrees today. A
plume of very dry air aloft will also works its way overhead.
Deeper mixing will tap into some of this, and have continued to
adjust dewpoints under the NBM-offered values. Afternoon RH
values are forecast to fall to around 25 percent (locally
perhaps a bit lower) which will lead to a bit of an increased
fire danger given dry grasses and winds gusting to around 25 to
30 mph. Will issue a Special Weather Statement across parts of
the area to highlight this.

Clouds will gradually increase late tonight and into Tuesday
morning as a low amplitude shortwave pushes eastward out of
Iowa. With cooling 500-400 mb temperatures, some increase in
mid-level instability is forecast. At this point, forecast
soundings just look a bit too dry in the sub-cloud layer to
warrant an addition of precipitation chances, but can`t rule out
some light shower activity from late morning into the mid
afternoon. Otherwise, expecting another breezy day with gusts
around 25 mph during the afternoon.

Another surface low will move across northern Wisconsin and
Michigan on Wednesday. The attendant cold frontal passage looks
dry at this point, but this system will drive yet another
increase in northwesterly breezes. High pressure will briefly
build in across the region Wednesday night/Thursday morning, but
this will be short- lived as the next area of low pressure
develops across the Minnesota Arrowhead and subsequently shifts
across the northern Great Lakes into Thursday night. Latest
guidance suggests this system will have a bit more moisture to
work with, leading to a blossoming area of showers, and perhaps
some embedded/isolated thunderstorms Thursday night/Friday
morning. Yet another period of breezy northwesterly winds will
occur on Friday.

While model spread increases quite a bit heading into the
upcoming weekend, there`s a signal for an additional round of
cyclogenesis in the vicinity of the remnant baroclinic zone left
over from the repeated cold frontal intrusions. Just how this
low development evolves remains unclear at this range, but an
additional period of showers appears plausible during this
timeframe. There`s also a smattering of guidance that suggests
that a transition to some snow can`t entirely be ruled out,
although have limited this mention in the gridded forecast given
uncertainties at this range. Regardless of this system`s
evolution, there is a strong signal that a much colder airmass
will shift into the area with a hard freeze for many areas
Sunday night and highs possibly struggling to make it out of the
upper 30s on Monday.

Carlaw

&&

.AVIATION /06Z TAFS THROUGH 12Z TUESDAY/...
Issued at 1057 PM CST Sun Nov 2 2025

Key Aviation Messages for the current TAF period:

- LLWS potentially overnight into early Monday morning

- Westerly wind gusts potentially as high as 30 kt on Monday

Winds remain out of the southwest. As a low level jet intensifies,
there is an increased risk for low level wind shear. However, gusts
have already started to increase at many terminals between 20 to 25
knots. If winds overperform, it is possible that LLWS can be
pulled early from the TAF. However, the expectation remains that
winds will decouple at or after midnight allowing surface winds
to diminish slightly for the potential for LLWS through
daybreak.

These stronger winds are associated with a weak cold front that will
pass over the area through the overnight. Most areas should remain
dry, but cannot rule out a sprinkle occurring through sunrise. After
sunrise, winds will slowly become westerly, if not just north of
true west. As deeper mixing develops, gusts 20 to 25 knots are
expected to prevail for much of the daytime hours, with strongest
gusts expected in the afternoon with peak gusts up to 30 knots.
Winds should decouple fairly quickly after sunset tomorrow night.

DK

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 5 PM CST this afternoon for
     Winthrop Harbor IL to Gary IN.

     Small Craft Advisory until 10 PM CST this evening for Gary to
     Burns Harbor IN-Burns Harbor to Michigan City IN.

&&

$$

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