646
FXUS63 KLOT 190516
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1216 AM CDT Fri Jul 19 2024

.KEY MESSAGES...

- Generally quiet weather pattern persists through the weekend.

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

&&

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

A deep, positively tilted 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 strengthening upper
level low early next week over the Plains 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 precip chances
around 30 to 40 percent. Temperatures are currently projecting
to be around seasonal norms as they nudge toward the mid 80s
next week.

DK

&&

.AVIATION /06Z TAFS THROUGH 12Z SATURDAY/...
Issued at 1215 AM CDT Fri Jul 19 2024

VFR conditions are forecast through the TAF period with FEW-to-
SCT 5000-6000 ft diurnal cumulus. Winds will be light westerly
to at times variable overnight through midday before an expected
inland push of the lake breeze turns winds easterly at
GYY/MDW/ORD. Guidance has trended a bit faster with the lake
breeze arrival at MDW and accordingly nudged up the wind shift
to 19Z. Have maintained 20Z at ORD for now but will continue to
monitor trends. Winds then return to light and variable Friday
evening with increasing high clouds toward Saturday morning.

Petr

&&

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

&&

$$

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