709
FXUS63 KLOT 071840
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
140 PM CDT Sat Sep 7 2024

.KEY MESSAGES...

- Chilly temperatures will bring an early sampling of fall
  tonight before extended period of above average, summer-like
  temps Monday through next weekend.

&&

.DISCUSSION...
Issued at 140 PM CDT Sat Sep 7 2024

Through Sunday:

Any lingering cloud cover this evening over northwest Indiana
will give way to clear skies tonight. Clear skies, light winds,
and low dewpoints should set the stage for strong radiational
cooling. Lows are expected to drop into the 40s CWA-wide, with
the one exception being the heart of the Chicago urban heat
island where lows should hold in the lower 50s. Certainly
plausible that some of the typically colder outlying locations
could dip into the upper 30s by early Sunday morning. The record
lows for Sunday morning for Rockford (37 1986) and Chicago (43
1986) should be safe, but probably only around 5F or so. Despite
the chilly start to the day, sunshine and dry conditions should
allow temps to rebound into the 70s Sunday afternoon.

- Izzi

Sunday Night through Saturday:

Broad mid-level ridging will develop over the Great Lakes into
early next week, and will remain in place through the work week.
At the surface, an expansive quasi-stationary high pressure
will extend from the Great Lakes to off the East Coast. This
will block off any moisture return and result in large diurnal
temperature spreads through the period.

Following another cool start to Monday morning, temperatures
will rebound into the upper 70s to lower 80s with strong mixing
holding dewpoints in the very comfortable range. As 925-850 mb
temperatures warm and mixing deepens, a gradual warming trend
will establish through the end of the week, with some 90 degree
highs possible Wednesday-Friday away from the lake. Abnormally
dry conditions of late should result in some dry ground feedback
given continued sunny daytime conditions and afternoon dewpoints
mixing out and likely ending up lower than NBM/current forecast
much of the week. Little to no threat of rain through the
upcoming work week and likely into next weekend as well, so
short-term precipitation deficits will continue to grow.

Carlaw/Izzi

- Izzi

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 1237 PM CDT Sat Sep 7 2024

VFR conditions are expected through the period with the
exception of some lingering SCT high-end MVFR lake effect clouds
at GYY this afternoon. N/NNE winds 10 to 15 knots should
persist through sunset, though some variability with periods of
directions just west of north can be expected. Winds will then
diminish while backing W/WSW through this evening, with W winds
10 to 15 knots most of the day on Sunday.

Kluber

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement through late tonight for ILZ006-ILZ103-
     ILZ104.

IN...Beach Hazards Statement through late tonight for INZ001-INZ002.

LM...Small Craft Advisory until 10 PM CDT this evening for the IL
     nearshore waters.

     Small Craft Advisory until 4 AM CDT Sunday for the IN
     nearshore waters.

&&

$$

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