602
FXUS63 KLOT 301836
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
136 PM CDT Sat Aug 30 2025

.KEY MESSAGES...

- A pleasant pattern will continue through the holiday weekend.

- An early fall storm system may move through the Great Lakes
  region toward the middle to end of next week accompanied by a
  shot of well below average temperatures.

&&

.DISCUSSION...
Issued at 136 PM CDT Sat Aug 30 2025

The final days of meteorological summer will wrap on the drier and
slightly cooler side. After a mostly cloudy Saturday, the rest of
the holiday weekend will feature abundant sunshine and pleasant
temperatures. All of this is courtesy of a widespread area of high
pressure across the Great Lakes region. This will change very little
over the course of the next few days a blocking pattern (quasi-rex
block) will keep the main forcing and frontal features positioned
across the central United States.

In the near/short term, cloud cover trapped below an inversion
should start to gradually erode this evening following the
passage of a trough axis shooting south from Wisconsin, though
The aforementioned high pressure will the hold in place Sunday
and even strengthen some on Labor Day. The low level airmass
will warm slightly each day, closer to 80 degrees inland after
the cooler day today. The slow moving upper wave and associated
front across the plains will scoot by to our southwest Tuesday
continuing the mild and dry conditions for one final day.

Attention will then shift to a more significant pattern change which
will send the first strong cold front through the Great Lakes region
of the season. This system will bring a period of rain showers
mostly along and behind the front Wednesday afternoon and
evening, as pre- frontal instability is fairly limited. Several
days of breezy conditions and autumnal temperatures, getting
down close to record cold for early September, will round out
the work week, with a statistically significant number (upper
10%) of ECMWF ensemble members depicting record/near record low
and low maximum temperatures in the region centered on Thursday.

In spite of the strong signal of an anomalous low pressure system
for early September, there is still decent spread as to far south
into the region the low will sink, which will directly translate to
whether the late period timeframe will feature any additional
rainfall. NBM PoPs have been mostly dry for late week, but we
can envision at least some showers at least during the
afternoon periods.

KMD

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 1202 PM CDT Sat Aug 30 2025

There are no significant aviation concerns through the period. Light
east-northeasterly winds will turn variable overnight before
returning to an easterly component Sunday. Broken VFR clouds will
scatter tonight, with scattered development again inland of the
lake breeze shadow tomorrow where a push of onshore winds will
bring winds closer to 9 kt in the afternoon. There is a low
chance for visibility reductions in fog tonight at RFD as the
boundary layer wind profile weakens overnight, however the
signal for this is higher north of the Wisconsin border.

KMD

&&

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

&&

$$

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