912
FXUS63 KLOT 182333
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
633 PM CDT Thu Jul 18 2024

.KEY MESSAGES...

- Hazardous swim conditions through this afternoon for IL Lake
  Michigan beaches, and through early this evening for IN
  beaches.

- Generally quiet weather pattern will persist through the
  weekend.

- Chances for showers and thunderstorms will return early next
  week (20-40% area-wide).

&&

.DISCUSSION...
Issued at 153 PM CDT Thu Jul 18 2024

A deep, positively tilited upper level trough prevails over
Quebec and Ontario extending southwestward over the Great Lakes
and mid-Mississippi Valley. With lingering mid level moisture
and some diurnal heating, some light fair weather cumulus around
5000 feet dot the skies. Otherwise quiet conditions will
continue as the upper level trough axis very gradually moves to
the east.

Models are suggesting some minor ridging and height rises
through tonight providing higher confidence in drier conditions.
Another weak wave is forecast to move down the longer wave on
Friday, but with higher p-wats to the southwest away from the
area, no precipitation is expected. Surface high pressure will
grow into the weekend allowing temperatures inland to gradually
creep up into the low 80s, while east to northeast winds will
help keep cooler 70s along the lakeshore.

Ensemble models are still suggesting a strengthen upper level
low early next week over the Plains that will slowly drift over
the forecast area early next week. The potential for scattered
shower and thunderstorm activity could be to our west as early
as Sunday before gradually moving east through Wednesday.
Guidance has kept the bulk of the activity in the traditional
diurnal range, so felt it was appropriate to keep the chance
around 30 to 40 percent. Temperatures are currently projecting
to be around seasonal norms as the nudge toward the mid 80s next
week.

DK

&&

.AVIATION /00Z TAFS THROUGH 06Z SATURDAY/...
Issued at 633 PM CDT Thu Jul 18 2024

The only forecast concern this period is an expected lake breeze
Friday afternoon. Mainly northeasterly winds are expected to
become light and variable this evening. If a wind direction
does occur tonight, it will likely be southwest. Winds may tend
to favor a more west/northwest direction Friday and then are
expected to shift easterly with a lake breeze for ORD/MDW and
earlier at GYY. cms

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...Beach Hazards Statement until 7 PM CDT this evening for INZ001-
     INZ002.

LM...Small Craft Advisory until 7 PM CDT this evening for the IN
     nearshore waters.

&&

$$

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