296
FXUS63 KLOT 281134
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
634 AM CDT Wed Oct 28 2026

.KEY MESSAGES...

- Above average temperatures to persist through the upcoming
  weekend, though today looks the warmest.

- While not a wash out, there will be some periodic chances for
  showers and perhaps isolated thunderstorms at times late
  tonight through the upcoming weekend.

&&

.DISCUSSION...
Issued at 257 AM CDT Wed Oct 28 2026

Today is shaping up to be an unseasonably mild day area-wide.
High temperatures are forecast in the low to mid-70s with breezy
southwesterly winds gusting up to 25 mph this afternoon.

While quiet weather is expected locally today, focus remains on
a shortwave impulse tracking eastward into southern Manitoba
early this morning. This feature will stay well north of our
region today and tonight. However, an associated surface low
will push a cold front southward into our area on Thursday.
Although the strongest forcing will pass well to the north,
unseasonably high low-level moisture (dew points in the mid-to-
upper 50s) beneath steepening mid-level lapse rates along the
boundary will bring isolated to widely scattered showers late
tonight into Thursday.

Shower chances (and possibly a few non-severe thunderstorms)
are forecast to increase to 20-40% across northwestern IL for a
period after midnight tonight. While some of this activity may
work its way eastward into parts of the Chicago metro into the
predawn hours of Thursday, it appears the coverage will be at a
diurnal minimum as it moves ahead of the primary frontal
boundary still to the northwest of the area. However, renewed
widely scattered development looks favorable along the front as
it shifts into the I-80 corridor and points southward Thursday
afternoon.

Although there is not a big push of colder air in the wake of
this front, temperatures will be turning cooler (dropping into
the 50s by sunset) in its wake Thursday afternoon and evening.
Cooler (more seasonable) weather is then expected to persist
Friday into the weekend as onshore easterly flow and extensive
cloud cover (and even rain at times) persists. Highs are
generally forecast to be in the 60s. However, temperatures could
end up struggling to climb out of the 50s, particularly across
northern IL on Saturday.

Ensemble guidance suggests a series of impulses will track from
Mexico east-northeastward into the Lower Great Lakes region
during the weekend, followed by a stronger system moving slowly
across the central U.S. next week. This will bring periodic rain
chances from Friday night through next week. However, dry
stretches are still expected between systems. Currently, the
highest rain chances appear to be Friday night into Saturday,
and again early to mid-next week. This may allow for a dry
window late Saturday, just in time for outdoor Halloween
activities.

KJB

&&

.AVIATION /12Z TAFS THROUGH 18Z THURSDAY/...
Issued at 634 AM CDT Wed Oct 28 2026

Key messages for the 12Z TAF period:

* A potential LLWS shear set up tonight

* Light rain possible overnight into Thursday morning with MVFR
  potential after daybreak

Light S to SSW winds early this morning will go 10 to 15 kt out
of the SSW for the late morning and afternoon. A relative lull
is expected during the late afternoon and early evening before
10 to 15 kt returns for the late evening and overnight. A
nocturnal low level jet will bring as many as 45 kt of SW flow
down to 2 kft AGL overnight. With breezy winds anticipated at
the surface, left an explicit mention out of the TAFs for this
cycle.

A system of widely scattered, light rain showers will move
across the area overnight into Thursday with a consistent signal
for a period of MVFR cigs after mid-morning. Potential is
largely low enough to omit mentioning in the TAFs for now.
However, a PROB30 was introduced at the Chicago sites after 14Z
mostly to highlight the MVFR potential.

Doom

&&

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

&&

$$

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