Influx of colder air riding well-developed “full-fetch” northerly winds to set the stage for possible lake-effect snow showers here



Lake-effect snow shower chances will be on the rise in the days to come. While flurries are to flutter to earth at times Friday, it appears the greatest snow threat comes into play in the counties adjacent to Lake Michigan Friday night into Saturday night.



Developing atmospheric conditions during that time frame—most notably the influx of cold air which is to increase the rate at which temps fall through the lowest mile of the atmosphere—will encourage air traveling down the lake to rise  and cool, producing lake clouds and snow showers in the process.




All of this is to take place despite the fact that meteorological spring has begun with March’s Friday arrival.



Though warmer temperatures become more frequent in the months ahead—March, after all is the Chicago area’s fastest warming month—the month of March is also known for its meteorological volatility.




At one time or another over the past 142 years, the month has played host to temperatures varying by as much as 100-degrees from its warmest-ever 88-degree reading to its coldest-ever 12-below.


Just-completed February 2012-13 has been the most “wintry” of the winter months in an otherwise fairly mild and low-snow-producing December through February Chicago weather regime




February 2013′s been a snowy, colder than normal month, very different with the two meteorological winter months which preceded it.




82% of Chicago’s 2012-13 seasonal snow fell in February—16.1 of the 19.6″ now on the books. February snowfall here finished 7″ above normal! Not surprisingly, all that snow played havoc with February’s sunshine. Sunny days here have been in comparatively short supply of late. Chicagoans saw just 35% of February’s possible sun versus the month’s normal allocation which comes to 47%.




February’s 26.2-deg average temp ended up 1.5-degrees below normal  and 6.7 degrees colder than the same period a year ago!




Meteorological spring’s now underway


The three-month meteorological spring season (March, April and May) began just after midnight this morning. March will pick up 84 additional minutes of sunlight before the month ends. Normal Chicago daytime highs warm from 40 on March 1 to 53-degrees by March 31.



Re-instatement of Daylight Saving Time just over a week away


Another sign of spring is the upcoming change back to Daylight Saving Time which takes place a week from this Sunday (March 10). That’s when clocks are advanced an hour.




New early week snow system?


Thursday evening model runs returned to a line of reasoning which puts an early-weekAlberta Clipper-type system on a more northerly track, suggesting the potential for snow in Chicago Monday and Monday night. That’s a forecast we’ll be monitoring and updating here as we move into the weekend.