Saturday, January 22, 2011
Global warming really kicking Chicago's ass this winter...
By Meteorologist Tom Skilling
Chicagoans shivered through the coldest weather in two years Friday. A morning low of -4 at O'Hare and -1 at Midway marked the first time city thermometer readings had dropped below zero in more than a year. A -3 or lower temperature hadn't occurred at O'Hare since January 16, 2009.
It was the most heavily snow-covered west and northwest suburbs which bore the brunt of the chill. Morning lows dropped to 14-below at Weather Bug sensors in McHenry County's Harvard, 13-below at De Kalb, 12-below at Rochelle, 10-below at South Elgin and 9-below at Algonquin, Schaumburg and Carpentersville.
The city's official daytime high at O'Hare never made it out of single digits, topping out at 8-degrees. Midway managed an 11-degree high while temperatures at the lakefront surged to 14-degrees.
Ice crystals, mistakenly referred to as "steam" on cold mornings here, could be seen rising off the lake early Friday--a testament to the cold air's intensity. The process which leads to this occurring is known as "sublimation", and occurs when water vapor goes directly to its solid state as crystals form in the frigid air above the comparatively warm lake water. Only the coldest air masses which visit the area produce such crystals.