By Tom Skilling
Only one in 11 summers since official records began here 140 years ago have produced temperatures into the first week of August as warm as this year. Chicago's average meteorological summer temperature since June 1 has been 74.6 degrees--a reading more than 3 degrees above the long term average and warm enough to rank among the 11 percent of warmest summers on record here to date. 84 percent of the season's days have posted temperature surpluses.Yet for all of Summer 2010's warmth, it's been 15 days since the last official 90-degree high was recorded here--a situation which comes to an end with Sunday's predicted 93-degree high. Hot, extremely muggy weather is predicted to build back into the Chicago area then and dominate the coming work week. Re-establishment of the storm-producing "ring of fire" pattern is to occur simultaneously and computer model rainfall estimates range from 0.52" to more than 2" in the coming week. A typical week this time of year produces 1.05" of rain. And with 1.50 to 2" of water to be evaporated in the mid 70-degree dew point air predicted to take up residence here, it's entirely possible narrow corridors of the Chicago area--much as happened last week--could be subjected to driving downpours generating rainfalls well in excess of the 2" top figure being put forth by models at present.
Storm development is likely to display a strongly "diurnal" tone in the coming week--which is to say daytime heating is apt to play a big role in initiating thunderstorm formation in the sultry, hot environment predicted to take shape here.
The renewed northward push of hot, humid air has prompted the issuance of excessive heat watches to Chicago's west for the weekend. Watches for extreme heat were hoisted late Friday in downstate Illinois as well as sections of Missouri, Iowa, Kansas and Nebraska for the weekend--and are likely to expand into other sections of the country's Heartland in coming days.
Thunderstorm outflows spared Chicago the worst of the heat which broiled downstate Illinois and Indiana much of the past week with 100-degree temperatures and dew points which surged into the 80s, producing 120-degree-plus heat indices. The role thunderstorm "outflows"--the term used to identify the rush of rain-cooled air out of thunderstorms--plays in the coming week, may have a significant bearing on daily high temperatures. For the moment, predicted readings for the period are in the 90s all week.
Chicago area's mold count nears "alert" level Friday
The heat and plentiful rain of recent weeks has led to a bumper crop of mold spores--and never more so than on Friday. Loyola Gottlieb Hospital's mold count, produced by Dr. Joseph Leija and his staff, surged to a five-year high--and nearly to "alert" levels Friday. The count was 49,789 spores per cubic meter--alerts are issued when the mold counts reach 50,000.
Dr. Leija cautioned that symptoms such as headaches, sinus congestion, runny noses and fatigue, could be suffered by some area residents and recommended allergy sufferers stay indoors Friday with windows closed and air conditioners, if available, turned on.
589 wildfires burning across Russia in record 100-degree heat; more than a half million acres ablaze; heat wave may not abate for until the week after next
The situation in Russia continued to worsen Friday in the midst of the country's worst heat wave on record. The number of wildfires, which were burning in the heat across more than half a million acres Friday--shrouding Moscow and other Russian cities in a cloud of thick smoke that set off smoke detectors in some buildings and forced residents to don face masks in order to breathe--continued to grow. 460 fires burned Monday, but Friday's count jumped to 589.
Moscow's high temperature Friday hit 102 degrees. The heat wave shows no sign of breaking through the coming week. Nearby Finland, in the grip of the same dome of hot air, recorded its highest summer temperature ever Friday.
Several global weather forecast models are hinting the extreme heat, which likely has another week to run, may well break down next weekend or in the week which follows. Until then, record temperatures, polluted air and extreme drought will continue to plague Russia.
Chicago sunsets continue colorful as northwest winds aloft guide Canadian wildfire smoke into the area
A mammoth plume of wildfire smoke, extending thousands of miles from Canada's arctic circle south into the Midwest and east to Pennsylvania, remained draped across the Chicago area, lending skies here a hazy appearance and producing yet another evening of eye-catching sunsets Friday night.
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