Cook County Illinois Weather Forecast Discussion

430
FXUS63 KLOT 131724
AFDLOT
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1224 PM CDT Mon Oct 13 2025
.KEY MESSAGES...
- A slight chance (20%) for showers through midday today.
- A chance (30%) for showers Tuesday night.
- The pattern turns more active heading into the upcoming
  weekend with increasing rain chances (30-50%).
&&
.UPDATE...
Issued at 1028 AM CDT Mon Oct 13 2025
Light rain showers will persist along and north of Interstate 80
this morning, and while many area will only see a trace of
rainfall, we continue to see enough forcing ahead of the cold
front to lead to some visibility reductions in a few of these
showers. Expect these to decay farther eastward as you get
removed from deeper forcing across northern Illinois and
southern Wisconsin.
KMD
&&
.DISCUSSION...
Issued at 147 AM CDT Mon Oct 13 2025
Light showers/sprinkles continue to dissipate across northwest
IL as they move east into a drier airmass. The lower levels will
slowly saturate this morning and additional isolated showers
are possible. While many areas may stay dry or just see
sprinkles, have included 20% pops for showers through midday for
the northwest half or so of the local area. This activity looks
to weaken/dissipate by early/mid afternoon.
While current temps are generally in the 50s north of I-80,
mostly cloudy or cloudy skies this morning will likely limit the
temperature rise some. But some partial clearing this afternoon
may allow highs to rebound before sunset. Highs in the lower to
mid 70s look on track, with perhaps the coolest temps in the
60s across far northeast IL.
A cold front will move across the area tonight shifting winds to
the northeast, which will continue through Wednesday, allowing
for a larger temperature gradient across the area with 70s well
inland and 60s for areas closer to the lake.
Precip trends continue to go up and down for Tuesday night with
a weak disturbance moving across the area. No changes to the
blended low chance pops for Tuesday night but overall confidence
is low for precip trends. Best chance appears to be north of
I-80 with perhaps some potential for any precip that develops to
be north into southern WI. There is now another low chance for
showers Thursday morning as another wave lifts northeast near
the area. Similar to Tuesday night, better chances may end up
just north of the area into WI.
The end of this week into the weekend still looks active though
there is some potential precip chances may be short in duration
with a cold front moving across the area Friday night into
Saturday and then pushing east of the local area. ECMWF develops
a surface low along the front, slowing the overall pattern and
keeping rain chances for most of the weekend. Blended pops are
now high chance to near likely for several periods. Made no
changes but still several days away and changes can be expected.
cms
&&
.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1221 PM CDT Mon Oct 13 2025
Sprinkles, or a few passing light showers will move through the
airspace through early afternoon, with the highest likelihood
for these to persist along and west of ORD/MDW.  Low to mid
level VFR cloud cover with bases around 4-7kft will then
continue into tonight. Otherwise, expect light and variable
winds either side of S (more SW at ORD/MDW) to turn north-
northeasterly later in the day as a cold front drops into the
area. Thereafter, northeasterly winds will persist through the
remainder of the TAF period. With these NE winds comes the
chance for cloud bases to lower to MVFR closer to the lake
Tuesday morning, and including ORD and MDW. With the chance
currently at around 30# will hold VFR conditions in the TAF at
this point.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
Visit us at weather.gov/chicago

NWS LOT Office Area Forecast Discussion