SEVERE WEATHER UPDATES: February 2008 Archives

Tracey Surface provides us this photo of Tuesday afternoon’s snow as it swept into Montrose Harbor earlier this afternoon. Many thanks Tracey! By late evening (5:30 p.m.), Chicago area snow tallies have reached the 2-5” range—including 2” at O’Hare, 3” at Downers Grove and our meteorological colleague Steve Kahn reports 4” is down at Arlington Heights. Chicago’s Midway Airport—where the mid-afternoon 2007-08 seasonal tally has risen to 49.7” (14.7” of it having falling in February alone)—is likely to have played host to a total of 50+” before the evening ends, says veteran Midway and Chicago weather observer Frank Wachowski. Frank also reports this snow, because of the cold temperatures in which it has formed and fallen, has a 22 to 1 snow to water ratio—indicating this snow has more than twice the volume of conventional snow here.

Radar (at 5:45 p.m.) is indicating a band of snow is approaching from the west—snow likely to be reinforced by lake moisture riding NE winds. So the snow’s not done as of this posting—but will end later tonight. It’s not the last snow likely to occur here in the coming week. Though glorious (and welcome) sunshine is due Wednesday—more snow is predicted Thursday (Valentine’s Day) night. The area’s lack of February sun is running at record levels. Only 12% of Chicago’s possible sun has occurred—February’s “normal” tally is 46%.

More on WGN-TV’s Nine O’Clock News Tuesday evening, on our wgntv.com “weather blog” and in Wednesday’s Chicago Tribune.

Tom Skilling
WGN-TV Chief Meteorologist

Photo courtesy: Tracey Surface, Chicago

We’re boosting our Chicago accumulation forecasts further, a foot or more of snow likely in parts of the city—much lighter amounts south

The early onset of snow suggests even higher storm snow totals are likely in the city. Expectations precipitation would start as a rain/sleet mixture in the northern suburbs due to a layer of warm air aloft have NOT materialized suggesting northeast winds have injected a layer of drier air in the lower atmosphere producing evaporative cooling there. That’s why snow has begun as soon as it has. This means assumptions that the first hours of this storm’s precipitation would come down as liquid or a mix must be updated and that moisture must be added to our predicted snow tally. As a result, it now appears likely 8-14” will fall from Chicago north and west. The presence of potential thunderstorms could lead to locally higher totals. Our latest in-house RPM (Rapid Precision Mesocale) model forecast now puts totals at 13” at O’Hare and 10” at Midway. The University of Wisconsin NMS model is even suggesting 12-18” totals in portions of northern Illinois.

Thus a major winter storm, by far this winter’s biggest to date, looks likely to produce serious travel problems well into Wednesday. We’ll update as new information becomes available.

Tom Skilling

Chief Meteorologist, WGN-TV/Chicago Tribune