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.
28 hours of sub-zero Chicago wind chills late Friday evening and counting
Gusty daybreak winds responsible for morning wind chills as low as 21-below in the city and 26-below at DeKalb, eased Friday--but not enough to permit wind chills to emerge from sub-zero territory.
By 11 pm Friday evening, the string of consecutive sub-zero wind chill readings at O'Hare had grown to 28 hours and counting.
Clouds and light snow approaching from the west combined to boost temperatures 4-degrees in just 3 hours at far west suburban DeKalb---a trend which was expected to lead to slowly rising overnight temperatures over the remainder of the metro area as well.
Meteorological winter now the 19th coldest of past 141 years here
With the arrival of Friday's bone-chilling arctic surge, Chicago's average temperature since the onset of meteorological winter on December 1 slipped to 21.5-degrees--5.5-degrees below the long-term average dating back to 1871. This winter season has become the 19th coldest to date in 141 years of official records here.
International Fall's 46 below temp Friday morning replaces 57 year old record
Nowhere was the cold air more intense than across the North Woods region of northern Minnesota and Wisconsin. International Fall's Friday morning low of -46-degrees replaced a 57-year old record. Other lows in the region included -46 at Babbitt and -43-at Big Fork--both in Minnesota. Lows of -31 and -20 were reported at Hayward and Rhinelander, Wisconsin. And in Illinois, morning temperatures tumbled to -11 at Champaign, -20 at Mt. Carroll and -18-degrees at Savanna.
A series of snowy disturbances ahead with modest accumulations; lake-effect snow flurries not out of the question the Bears/Packers game
A series of computer estimates of potential Chicago snowfall over the coming two weeks comes out to 4 inches of snow--close to the 4.7 inches average this time of year. The spread in the most recent 2 week snow projections from National Weather Service computer models ranges from 2.4 inches on the low end of the spectrum to as much as 7.9 inches of snow.
The onset of easterly winds off Lake Michigan Sunday threatens to activate lake-effect clouds and flurries which could continue into the Bears/Packers game in the afternoon.
2010-11 snows have topped normal full season tallies and still climbing out East; snowy pattern's nowhere near ending
The prolific snows which have so frequently hit the East this winter have led to tallies which exceed the amounts typically recorded over a full season. 2010-11 season totals through Friday as well as "percent of normal values" to date include 57.2 inches (275%) at Hartford, Connecticut; 49.6 inches (295%) at Boston; Portland Maine with 39.4 inches (186%), and 5.9 inches at Atlanta, Georgia (1,967% of normal).
By comparison, Chicago's official snow tally now stands at 24 inches (126% of normal).
Normal temps begin the long, slow seasonal climb toward spring and summer--but with 2-week forecasts suggest chill's not done
Chicago reaches a temperature benchmark Saturday--the point at which the city's "normal" readings begin rising, embarking on the long trip toward spring and summer temperature levels. The city's "normal" high temperature of 30-degrees increases to 31-degrees by February 1, 40 by March 1, 52 by April 1 and 64 by May 1.
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.
28 hours of sub-zero Chicago wind chills late Friday evening and counting
Gusty daybreak winds responsible for morning wind chills as low as 21-below in the city and 26-below at DeKalb, eased Friday--but not enough to permit wind chills to emerge from sub-zero territory.
By 11 pm Friday evening, the string of consecutive sub-zero wind chill readings at O'Hare had grown to 28 hours and counting.
Clouds and light snow approaching from the west combined to boost temperatures 4-degrees in just 3 hours at far west suburban DeKalb---a trend which was expected to lead to slowly rising overnight temperatures over the remainder of the metro area as well.
Meteorological winter now the 19th coldest of past 141 years here
With the arrival of Friday's bone-chilling arctic surge, Chicago's average temperature since the onset of meteorological winter on December 1 slipped to 21.5-degrees--5.5-degrees below the long-term average dating back to 1871. This winter season has become the 19th coldest to date in 141 years of official records here.
International Fall's 46 below temp Friday morning replaces 57 year old record
Nowhere was the cold air more intense than across the North Woods region of northern Minnesota and Wisconsin. International Fall's Friday morning low of -46-degrees replaced a 57-year old record. Other lows in the region included -46 at Babbitt and -43-at Big Fork--both in Minnesota. Lows of -31 and -20 were reported at Hayward and Rhinelander, Wisconsin. And in Illinois, morning temperatures tumbled to -11 at Champaign, -20 at Mt. Carroll and -18-degrees at Savanna.
A series of snowy disturbances ahead with modest accumulations; lake-effect snow flurries not out of the question the Bears/Packers game
A series of computer estimates of potential Chicago snowfall over the coming two weeks comes out to 4 inches of snow--close to the 4.7 inches average this time of year. The spread in the most recent 2 week snow projections from National Weather Service computer models ranges from 2.4 inches on the low end of the spectrum to as much as 7.9 inches of snow.
The onset of easterly winds off Lake Michigan Sunday threatens to activate lake-effect clouds and flurries which could continue into the Bears/Packers game in the afternoon.
2010-11 snows have topped normal full season tallies and still climbing out East; snowy pattern's nowhere near ending
The prolific snows which have so frequently hit the East this winter have led to tallies which exceed the amounts typically recorded over a full season. 2010-11 season totals through Friday as well as "percent of normal values" to date include 57.2 inches (275%) at Hartford, Connecticut; 49.6 inches (295%) at Boston; Portland Maine with 39.4 inches (186%), and 5.9 inches at Atlanta, Georgia (1,967% of normal).
By comparison, Chicago's official snow tally now stands at 24 inches (126% of normal).
Normal temps begin the long, slow seasonal climb toward spring and summer--but with 2-week forecasts suggest chill's not done
Chicago reaches a temperature benchmark Saturday--the point at which the city's "normal" readings begin rising, embarking on the long trip toward spring and summer temperature levels. The city's "normal" high temperature of 30-degrees increases to 31-degrees by February 1, 40 by March 1, 52 by April 1 and 64 by May 1.
