If yesterday’s Michigan temps seemed chilly, today’s are worse! Ironwood is still the coldest, but they are up a few degrees at -20 (before the -33 windchill of course). Most of the rest of the state is joining them below zero this morning. Detroit and Lansing are at -11, Marquette is at -15 and Grand Rapids is at a balmy 1.6 degrees!
Dr. Jeff Masters blog on the Extreme Cold Blast at Weather Underground, the site he founded and runs in Michigan says:
The most extreme cold air outbreak since 1994 is in store for much of the U.S. on Monday and Tuesday, as Arctic air behind a major winter storm invades the Midwest. The powerful 989 mb storm blasted the Upper Midwest on Sunday, bringing snows in excess of a foot over portions of Illinois, Michigan, Indiana, Missouri, and Ohio. The 11.4″ that fell on Sunday in Indianapolis, Indiana made it that city’s second snowiest day on record (the all-time record: 12.1″ on March 19, 1906); Flint, Michigan also recorded its second snowiest day on record: 14.5″ (the all time record: 15.0″ on November 28, 1937.) … The high temperature in Detroit on Tuesday is expected to remain below zero; the city’s list of days with a high temperature below zero is a short one, with only three such days in recorded history. The frigid air is being propelled by strong Arctic winds of 15 – 25 mph, which will generate dangerously low wind chill readings in the -30° to -60°F range from Michigan to Minnesota on Monday and Tuesday.
In the winter, the 24-hour darkness over the snow and ice-covered polar regions allows a huge dome of cold air to form. This cold air increases the difference in temperature between the pole and the Equator, and leads to an intensification of the strong upper-level winds of the jet stream. The strong jet stream winds act to isolate the polar regions from intrusions of warmer air, creating a “polar vortex” of frigid counter-clockwise swirling air over the Arctic. The chaotic flow of the air in the polar vortex sometimes allows a large dip (a sharp trough of low pressure) to form in the jet stream over North America, allowing the Arctic air that had been steadily cooling in the northern reaches of Canada in areas with 24-hour darkness to spill southwards deep into the United States. In theory, the 1.5°F increase in global surface temperatures that Earth has experienced since 1880 due to global warming should reduce the frequency of 1-in-20 year extreme cold weather events like the current one. However, it is possible that climate change could alter jet stream circulation patterns in a way that could increase the incidence of unusual jet stream “kinks” that allow cold air to spill southwards over the Eastern U.S., a topic I have blogged about extensively, and plan to say more about later this week.
Read on for more and to see a shot of Jeff shoveling 14″ off his metro Detroit roof!
PS: Curiously enough, there’s a Campus Squirrels photo group on Flickr.