Chicago’s longest sub-freezing spell in 23 years ended Monday after a 537 consecutive hour (22 day) run which started just after 1:30 a.m. Jan. 27. A 1984-85 string of 33 below freezing days was the last time the metro area had logged so many back to back sub-32° days. The degree of warming Monday was remarkable given all the snow still on the ground. That snowpack holds as much as 0.75" to 1" of water—moisture which is likely to percolate into any patches of soil which thaw in the 40° temps expected well into the coming weekend. This could mean the heavy rains predicted in a new storm this weekend may provoke localized flooding.
Powerful near-40 m.p.h. winds were able to override a great deal of the cooling effect which typically occurs over heavily snow-covered terrain. The winds blew 40° air several thousand feet aloft down to the surface. By day’s end, the snow-eating winds had slashed Chicago’s snow cover from 9" to just 5" by nightfall.
--By Tom Skilling, WGN-TV Chief Meteorologist
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
