Bring the sun out in February and warming is bound to follow. That was certainly the case Thursday. The day’s bright, blue skies, decorated from time to time by a few wisps of cirrus (ice clouds), was for many cause for celebration. Cloud-shrouded February had managed only 33 percent of its possible sun up to that point. The combination of unlimited sunshine and mild temperatures Thursday made it clear to many the march to spring is truly underway.
Area residents were treated to the mildest temperatures in 25 days. Highs hit 41 degrees at Midway and 45 at Chicago’s lakefront. Other highs from Weather Bug sensors across the metro area included 43 degrees at Gary, 42 at Winnetka and Oak Lawn, and 41 at Morton Grove, Burr Ridge, Downers Grove and Park Ridge.
O’Hare’s official 39-degree high fell just short of 40 and kept the growing string of sub-40 temperatures there going. With only 10 days left in February, Thursday’s failure to hit 40 moved the area another step closer to a February without a 40-degree high at the city’s official site. Only two Februarys in the past 140 years — one 1901 and the another in 1978 — have managed to escape without producing a single 40-degree reading.
Minor snow system due Friday night; more significant storm potential being monitored Sunday night/Monday
Two disturbances — the first fairly modest in scope, the second capable of growing into a storm Sunday night and Monday — are being monitored. Each may impact Chicago in coming days.
System one, which on Thursday produced a fresh 6″ cover of snow across western Nebraska near Ellsworth, sends a veil of cloudiness streaming across Chicago area skies Friday. It’s a development which is to ultimately take a toll on sunshine and, in so doing, probably restrain temperatures to levels a few degrees lower than Thursday — though still seasonable by late-February standards. An overcast predicted to be in place by evening is to lower and thicken expeditiously Friday night, leading to light snow in the hours beyond midnight. The snow may continue at times Saturday and, because of some pockets of warmer air aloft, may mix with some ice pellets or even a little drizzle.
Potentially more eventful for the Midwest is a second system which threatens to develop into a full-blown winter storm later this weekend into Monday. That system’s heaviest snow appears, based on early storm track projections, poised to sock an area from Missouri across downstate central Illinois and Indiana with a significant snow — potentially a half foot or more.
Chicago doesn’t completely escape this system’s reach in current forecast scenarios. Its northernmost snows reach the city amid strengthening northeast winds Sunday night into Monday. A series of computer-model snow estimates produces an average around 3″ in the city. It’s likely there may be lighter totals north in Wisconsin border counties and that heavier amounts could fall across southern sections of the metro area.
But it’s early in the storm’s life cycle. The system was off the West Coast late Thursday and therefore outside the reach of the land-based U.S. radiosonde (upper-air balloon) network. It’s eastward movement carries it into that network, where a more complete scan of its structure will occur, which can be incorporated in future computer forecast model runs. It’s not unheard of for the track of storms like this one to be adjusted farther north as this new data becomes available. Such an outcome would allow the storm to impact the Chicago area more significantly. We’ll keep you posted!
Februarys as snowy as this one have signaled above-normal snowfall continuing for the remainder of the season
February 2010 is currently the snowiest in 29 years of Chicago snow records. An in-house analysis of seven other snowy Februarys, with an eye toward the trend in snowfall which followed, reveals 5 of the 7 — 71% of them — remained snowier than the long-term averages.