759
FXUS63 KLOT 112026
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
326 PM CDT Sun Aug 11 2024

.KEY MESSAGES...

- Mainly dry conditions and warming temperatures through the
  first half of the week.

- Multiple waves, and a large-scale low pressure system impact
  the Midwest during the second half of the week, lingering into
  next weekend.

&&

.DISCUSSION...
Issued at 326 PM CDT Sun Aug 11 2024

Sunshine across the region this afternoon, along with mixed
diurnal cu fields have allowed temperatures around the area to
climb into the mid and upper 70s. Sfc high pressure will
continue to shift across the Midwest, continuing the dry
conditions across much of northeast Illinois into far northwest
Indiana to start the new work week. One item to note, another
weak upper level shortwave trof will drift across the southern
Great Lakes Monday. This will bring a chance of showers to
portions of central Illinois, as the sfc high pressure tries to
hold position in southern Wisconsin. Best chances for
precipitation late Monday morning through the afternoon appear
to be south of the I-80 corridor (20-30%), however cannot rule
out light shower activity between the I-80/I-88 corridor
(10-20%). With the low Td values, and 20-25 degree spread
between T/Td, this could limit precipitation chances as
saturation of the lower air column will take time.

Behind the passage of this shortwave, an upper-level ridge
builds across the central CONUS. With the ridge building,
temperatures closer to normal for this time of year will be
ushered into the Midwest on Tuesday. The brief "warmer"
temperatures get pushed off to the east mid-week, as the next
weather system begins tracking eastward from the southwest
corridor of Canada.

A large-scale low pressure system will begin developing across
far southwest Canada heading into the start of the new work
week. This will slowly evolve across the Pacific NW through
Tuesday, before beginning the eastward journey...reaching our
area during the second half of the week. The upper level ridge
will limit progress through mid-week, but break down during the
second half of the week. Current model camps have 2 separate
tracks of this low core, one through the north central Plains
and the other across the US/Canadian border. With the southerly
track, this would bring the core (upper-level and sfc system)
across the mid/upper Mississippi River Valley into the lower
Great Lakes region. This would bring more potential for
widespread continual storm activity near the low center. In
contrast, the northern track along the border would bring more
sporadic waves of showers and storms to the region. This system
will continue to track through the area next weekend, bringing
the potential of wrap-around activity on the backside through
next Sunday.

Baker

&&

.AVIATION /18Z TAFS THROUGH 00Z TUESDAY/...
Issued at 1222 PM CDT Sun Aug 11 2024

There are no major aviation weather concerns for the 18Z TAF
period.

NW winds will continue to gust to near 20 kt into the late
afternoon before subsiding to around 10 kt for the evening and
closer to 5 kt during the overnight. Westerlies are expected
tomorrow mostly under 10 kt. A lake breeze will attempt to
approach the Chicago terminals in the afternoon, although it
remains unclear if it`ll actually make it across the airfields.
Best guess as of now is no and winds will remain westerly,
although there is plenty of support on both sides. If it does,
winds on either side of the boundary should be moving at around,
most likely under, 10 kt. MDW has a seemingly better shot at an
afternoon wind shift than ORD. Most guidance that brings the
lake breeze through does so at around 20-21Z at both ORD and
MDW. VFR can be expected throughout the period.

Doom

&&

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

&&

$$

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