259
FXUS63 KLOT 152309
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
509 PM CST Sat Nov 15 2025

.KEY MESSAGES...

- Cooler, breezy and dry on Sunday with an elevated threat of
  wildfire spread.

- Rain chances return for Monday night into Tuesday.

- Another period of wet weather likely in the Thursday to Friday
  timeframe.

&&

.DISCUSSION...
Issued at 154 PM CST Sat Nov 15 2025

The unseasonable warm conditions in place across the area this
afternoon will are slatted to come to an end into tonight as a
cooler airmass filters into the area on breezy (gusts 25 to 30
mph) northwesterly winds setting up in the wake of a cold
frontal passage. As of this writing, the surface cold front is
already in the process of moving across eastern IL and
northwestern IN, though with the colder air lagging well behind
the front, there will not be a sharp drop off in temperatures
following its passage this afternoon. However, temperatures will
be falling off into the upper 40s to low 50s by mid to late
evening before bottoming out in the 30s overnight.

Conditions for Sunday will be dry and a good 15 to 20 degrees
cooler than this afternoons temperatures. Accordingly, with full
sun, the cooler airmass overhead will only support highs in the
upper 40s to around 50 (more typical type readings for this
time of year). In spite of these cooler conditions, there
continues to be a concern for the increased threat of wildfire
spread on Sunday, owing to the continued breezy winds (gusts up
to 25 mph) and very low dewpoints (falling into the teens during
the day). Current expectations are for afternoon relative
humidity values to bottom out in the 25 to 30% range. While this
will be near Red Flag criteria, it appears the winds will not
reach the sustained 20 mph threshold. Accordingly, while it will
be a breezy and dry Sunday with an increased threat of wide
fire spread, it does not look to reach the critical threshold
supportive of a Red Flag warning. Conditions will improve
through the evening as surface winds abate as a surface ridge of
high pressure shifts in over the area.

Cooler weather will persist through the middle of next week.
Otherwise, while the work week will began precipitation free on
Monday, rain chances will ramp up from west to east Monday night
continue into Tuesday morning. This period has, and continues
to be, the most favored period for some rain in our area as an
impulse emanating from southern CA traverses the central Rockies
and shifts out over the Mid-Mississippi Valley. The primary
P-Type continues to favor rain with this system, though I cannot
rule out the possibility for a few wet snowflakes or ice
pellets mixing in across parts of northern IL with the
precipitation onset Monday evening. Either way, not expecting
any impacts from wintry weather with this.

While some lingering widely scattered showers could persist at
times later Tuesday into Wednesday, the next period we are
watching for more widespread rain (maybe even with a period of
storms?) is Thursday into Friday. Model and ensemble guidance
continue to support an active southwesterly mid and upper-level
flow pattern setting across the central CONUS downstream of a
recharging southwestern CONUS trough later in the week. This
pattern will be supportive for a moisture laden area of low
pressure to track northeastward from the central and southern
Plains into the Great Lakes region later in the week. While
spread in the track, timing and strength of this system persist,
the signal for rain continues to increase in our area, and
given the pattern some decent rainfall could fall in our near
our area.

KJB

&&

.AVIATION /00Z TAFS THROUGH 06Z MONDAY/...
Issued at 509 PM CST Sat Nov 15 2025

Winds will ease a bit early this evening, but gusts are
expected to return with the arrival of a stronger northwesterly
LLJ tonight. Some periodic gusts around 30 kts are expected at
times late this evening. Gusts should then ease towards daybreak
on Sunday, but will re-develop through Sunday morning. VFR
conditions will prevail through the forecast period.

Carlaw

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory until 4 PM CST Sunday for Winthrop Harbor
     IL to Gary IN.

     Small Craft Advisory until 9 AM CST Monday for Gary to Burns
     Harbor IN-Burns Harbor to Michigan City IN.

&&

$$

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