733
FXUS63 KLOT 070511
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1211 AM CDT Wed May 7 2025

.KEY MESSAGES...

- Strong winds and much cooler temps expected behind a lake
  enhanced cold front Wednesday, the strongest winds and biggest
  temperature drop will be in closer proximity to the lake.

&&

.DISCUSSION...
Issued at 249 PM CDT Tue May 6 2025

Blocky pattern is expected to largely persist through the next
7 days with medium range guidance suggesting a more pronounced
Rex Block developing over the central/eastern portions of the
country this weekend into early next week. The upper ridging
that develops with the polar front jet will displace the storm
track and stronger belt of westerlies well to our north into
Canada. A cut off mid-upper level low is expected to develop
south of this ridge and meander around to our south this
weekend into early next week. By early next week there is
greater spread in guidance regarding where that upper low will
end up.

In the near term, attention is focused on a cold front that will
move across the western Great Lakes region late tonight into
Wednesday. As is common this time of year, the front will become
lake enhanced and charge more quickly southward down the lake
delivering a shot of much cooler air to the area. The
synoptically enhanced boundary will create a larger than typical
"footprint" of lake cooling Wednesday, with temps dropping into
the upper 40s along the lakefront, to 50s across most of the
Chicago metro area, to 60s well inland. Ahead of the front,
temps should soar well into the 70s to near 80 far to the south
and west of the lake.

It will remain cool, especially near the lake Thursday followed
by a warming trend Friday and Saturday. Temperatures this
weekend should be seasonably warm, but afternoon lake breezes
will keep temperatures cooler near the lake. While confidence
begins to decrease some early next week, if the upper low
remains safely south of the area, then temps could warm even
more early next week.

Generally dry conditions are expected much of the upcoming 7 day
period. Still maintained a slight chance of showers across our
western CWA tomorrow afternoon with the cold front, however it
may be more sprinkles if anything given the very high CCLs
(nearly 10 kft) and dry sub-cloud layer. After some cloudiness
tomorrow into early Thursday, it looks like there will be an
extended period with clear or mostly clear skies to close out
the work week and possibly through the upcoming weekend.

- Izzi

&&

.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1211 AM CDT Wed May 7 2025

The main aviation weather concerns for the 06Z TAF period
include:

*Possible MVFR cigs Wednesday night

Light and variable winds through the night will go NE at around
10 kt by mid-morning. Gusts are expected to build into the 20
to 25 kt range, possibly higher on occasion, behind a cold front
this afternoon. NE winds will remain breezy through Wednesday
night. Additionally, there is a signal for possible MVFR cigs
behind the front, although VFR is currently favored throughout
the period.

Doom

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory from 11 AM this morning to 4 AM CDT
     Friday for the IL and IN nearshore waters.

&&

$$

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