549
FXUS63 KLOT 102345
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
645 PM CDT Fri Oct 10 2025

.KEY MESSAGES...

- Isolated showers are possible through this evening, followed
  by a few isolated light lake effect rain showers or sprinkles
  over northeast Illinois on Saturday.

&&

.DISCUSSION...
Issued at 227 PM CDT Fri Oct 10 2025

A cold front currently encroaching on the northwest CWA will
drift southeastward across the CWA through tonight. Cannot rule
out some sprinkles along the front, especially with a passing
upper-level trough this evening. A NNE wind shift behind the
front will then advect a band of lake effect clouds into
northwest Indiana and especially northeast Illinois late tonight
through much of Saturday. Low inversion heights under 5-6kft
will greatly limit precip potential, but marginal delta temps
and daytime diurnal enhancement could generate isolated light
lake effect rain showers or sprinkles over northeast Illinois
late morning into the afternoon.

The overall pattern across the central CONUS will remain
relatively quiet next week with low-amplitude ridge anchored
across the central CONUS. A trough tracking northeast to south-
central Canada will push a weakening cold front toward the
forecast area early in the week. A trailing mid-level front may
bring some decaying showers or sprinkles over the area Monday
afternoon and evening, but dry conditions are expected at this
time. A surface cold front will then shift southward over the
area Monday night and stall south of the forecast area by
Tuesday morning. Weak WAA and a mid-level disturbance rounding
the ridge may yield a period of light rain Tuesday night. The
central CONUS ridge will then amplify across the Mississippi
River Valley late in the week, likely resulting in dry and
seasonably warm conditions.

Kluber

&&

.AVIATION /00Z TAFS THROUGH 06Z SUNDAY/...
Issued at 645 PM CDT Fri Oct 10 2025

Main aviation forecast concerns are detailing some periods of
MVFR ceilings for the Chicago terminals, as well as a shift to
north-northeast winds behind a cold front late this evening.

Early evening surface analysis depicts an area of low pressure
just east of Lake Superior, with a cold front trailing across
southeast WI and into eastern IA. Spotty showers associated with
a mid-level disturbance have moved east of the region. Some
lingering mainly VFR stratus/stratocu has been stubbornly
redeveloping on its trailing flank, slowing clearing a bit this
evening. There may be some patchy 3 kft MVFR bases around the
Chicago terminals early this evening within the moist axis ahead
of the cold front, though mainly VFR conditions are expected.

Surface winds currently from the west-southwest will gradually
veer more west-northwest through the evening, before the front
passes and shifts winds northerly. Latest guidance trend
suggests winds may flip between 350-020 deg behind the front
for a time before becoming steadily northeast Saturday morning,
and eventually easterly later Saturday evening. With the
northeast flow off Lake Michigan Saturday, lake-induced stratocu
is expected with bases ranging from 2500-3000 ft over and near
the lake to VFR farther inland.

Ratzer

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory from 1 AM to 10 AM CDT Saturday for the
     IL nearshore waters.

     Small Craft Advisory from 3 AM to 1 PM CDT Saturday for the IN
     nearshore waters.

&&

$$

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