388
FXUS63 KLOT 071716
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1216 PM CDT Mon Sep 7 2026

.KEY MESSAGES...

- The week looks fairly pleasant with the only threat for rain
  being Tuesday night through Wednesday.

&&

.DISCUSSION...
Issued at 1216 PM CDT Mon Sep 7 2026

Mostly sunny skies, relatively low humidity values, and
seasonably warm temperatures in the upper 70s to lower 80s are
making for a beautiful Labor Day in the Great Lakes thanks to a
large high pressure system centered over southern Ontario.
Tonight looks similarly pleasant with overnight lows around 60,
low humidity values, and light winds. Suppose a few patches of
ground fog cannot be ruled out toward day break near river
valleys and farm fields, but will withhold mention in the
forecast for now.

Tomorrow, the semi-persistent upper-level ridge over the
central United States will begin to flatten as an upper-level
trough and associated surface low lift into central lower
Canada. An increase in south to southwesterly winds will advect
a warmer airmass into the region with highs poised to rise into
the mid to upper 80s. A lake breeze should develop by early
afternoon and stall inland with cooler temperatures along the
lakeshore.

Tomorrow afternoon and evening, showers and thunderstorms will
develop in a low-level confluence axis across Iowa and
Wisconsin. With time, the activity will tend to outrun any
upper-level ascent leading to a gradual weakening trend while
approaching and especially crossing the Mississippi River. Can
nevertheless still envision scattered showers and perhaps a
storm moving across the area overnight through Wednesday
morning, but will cap PoPs at 60% to signal a lower coverage/QPF
event.

After morning showers, Wednesday afternoon is looking
relatively quiet. Highs will depend on how fast clouds clear and
should range from the low to mid 80s. A few showers and storms
may attempt to develop across the south and east portions of our
forecast area depending on where any residual front stalls.

Thursday and Friday look pleasant as a surface high pressure
system work into the Great Lakes region. Opted to cut NBM
temperatures by several degrees each day to feature highs
generally in the mid to upper 70s both days. Ensemble guidance
then suggests warming temperatures by the weekend accompanied by
the next opportunity for rain.

Borchardt

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1216 PM CDT Mon Sep 7 2026

No major forecast concerns at the terminals for this TAF period
as high pressure will remain in control. Winds this afternoon
will continue to be a bit on the breezy side with speeds around
10-12 kts out of the east-southeast but will ease around sunset.
Directions will veer overnight before settling into a south-
southwest (180-190) orientation Tuesday morning with speeds
increasing once again into the 8-10 kt range. Otherwise, expect
mostly sunny skies today to give way to gradually increasing VFR
cirrus late tonight through Tuesday.

Yack

&&

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

&&

$$

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