Coolest temperatures in 2 weeks stick around
It was only five days ago that area heat enthusiasts were relishing a temperature of 91
degrees. Dramatic changes in the upper atmosphere, including the reappearance of a
dome of warm air aloft to the west of Greenland over the Davis Strait -- a pattern
behind Chicago's persistent winter and spring chill -- have this week's weather on a
much different track. The pattern produces northwest steering winds aloft that tug cool
Canadian air south across the Midwest. Lacking the moisture delivered by south winds
from the Gulf of Mexico, this atmospheric set-up greatly limits thunderstorm
development -- a blessing for Chicago-area residents who have been forced to
contend with flooding in the past week. Only the Fox River in this area has yet to crest,
a benchmark to be reached Wednesday morning.
COOLEST WEATHER HERE IN TWO WEEKS
Monday's 72-degree high was Chicago's coolest since the 69-degree high June 3 and
the second chilliest daytime high to date this month. Temperatures over the coming
five days (through Saturday) will average 18 degrees cooler than the same period a week
ago. But warmth and humidity are to stage a comeback this weekend.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune