Chicagoans are likely to enjoy the sunshine predicted Thursday and Friday. Sun’s been in shorter than usual supply in recent days — in fact much of the month. The metro area has received 25% less February sun than a year ago and 13% less than average. With 15.5″ of snow to its credit, February’s been the snowiest here in 29 years. It’s not surprising such a month would fall short in the sunshine department. To date, only a third (33%) of the month’s “normal” sunshine has been logged — way down from the 58% on the books a year ago. A typical February hosts 46% of its possible sun.
While the Southwest and West are awash in unseasonably mild air, cold air remains in firm control over much of the eastern three-quarters of the nation. Frost and freeze warnings were posted for a second consecutive night across north Florida and are likely to be issued again Thursday night. That area’s been shivering in chilly nighttime temperatures, as an atmospheric blocking pattern continues holding cold air in place east of the Rockies.
Florida lows dropped below freezing early Wednesday in Tallahassee (23 degrees), Jacksonville (27), Apalachicola (29) and Panama City (32), and sub-freezing temperatures were predicted a third of the way down the Florida Peninsula overnight.
In marked contrast, residents of the Southwest and West continue basking in unseasonably warm air. Phoenix topped out at 78 degrees Wednesday while downtown Los Angeles recorded 80. The mild air extended north along the West Coast and included a 64-degree high in San Francisco and 51 degrees in Seattle.
Chicago’s been snowier than Anchorage, Alaska
The winter 2009-10 pattern across North America, dominated by cold air in the east and mild air far west, has contributed to the production of more snow in Chicago to date (45.4″) than the 44.4″ thus far in Anchorage, Alaska.
Period of early weekend light snow may be followed by more important Midwest snow-maker
The first of two snowy spells expected to impact sections of the Midwest including Chicago in the coming week is just days away. Light snow may streak into the area for a time Saturday — but a more substantive snow system is being monitored for late Sunday into Monday. That one’s currently off the West Coast but is expected to sweep across the Rockies early in the coming weekend. The track it follows is likely to influence how it distributes its snowfall.
Projections generated by National Weather Service supercomputers late Wednesday hint at a potentially significant snow event centered on central Illinois and Indiana late Sunday into Monday — but with snows likely to extend north into Chicago where some accumulation may also occur. A more northerly track — with the center of the system crossing central rather than southern Illinois and Indiana — could shift that system’s most significant snowfall north into the Chicago area. That scenario will be monitored very closely in the days ahead as the Pacific system comes ashore, where its structure can be more thoroughly measured by land-based weather balloons.
45 of the 167 biggest Chicago snows (6″-plus) have occurred beyond this date
About a third of Chicago’s measurable snows occur from this point in the season forward. And, of the 167 six-inch or greater snows which have occurred here over 125 years of records here, 45 of them (33%) have occurred from Feb. 18 forward.