Heat and humidity back in town by midweek

Scattered showers and thunderstorms popped up in an irregular pattern Sunday over the
Chicago area and northwest Indiana. There were many reports of pea- to quarter-size
hail. Half-inch hail covered the ground at 5:30 p.m. just south of Evanston. This
unstable air, associated with low pressure centered well to the north and east of Lake
Huron in Canada's Quebec province, moved to the east overnight.
Light northerly winds on the front side of cool high pressure over the western Great
Lakes will prevail over Chicago today with inland heating conducive to the setting up of
a lake breeze, resulting in cooler shoreline temperatures this afternoon.
DOWNPOURS COULD BRING MORE WORRY
A change in the upper-level jet stream pattern will open the gates for warm, humid air
to flow into the Midwest starting Wednesday. Weak warm and cold fronts will not
influence temperatures greatly, but will add instability to an already unstable
atmosphere. Frequent periods of showers and thunderstorms are likely, beginning later
Wednesday and continuing through Friday. Heavy rain with some of these storms could
bring more worry to residents of Iowa, Missouri, Wisconsin, Illinois and Indiana, who
are weary of battling flood-swollen rivers and streams.
--By Paul Dailey, WGN Weather Center Meteorologist