Is there any validity to the legend about Groundhog Day?
In American folklore, Groundhog Day is an indicator of the weather for the remainder of the winter. The hibernating groundhog digs out of his burrow at sunrise on Feb. 2, so the legend goes. If he sees his shadow (a sunny morning), he heads back into his burrow, thereby indicating another six weeks of wintry weather. A cloudy morning creates no shadow and the groundhog stays out, indicating an early and mild spring.
In short, “Shadow, go; cloudy, howdy!” The Feb. 2 appearance of Punxsutawney Phil (of Punxsutawney, Penn.) is the most popular of many Groundhog Day celebrations.
Is the legend reliable? The authoritative American Meteorological Society, says, “There is no convincing statistical evidence to support this (Groundhog Day) belief.”
Low pressure and the associated cold front will move east through Chicago Sunday morning. Overnight rains will continue this morning before diminishing behind the cold front this afternoon. The combination of 40-degree-plus temperatures and dewpoints, strong winds and up to an inch of rain should be enough to pretty well eliminate any snow cover over northeast Illinois. Much of this rain and water from snowmelt will run off, causing pooling in low-lying, poorly-drained areas, as well as rises on rivers and streams, many of which are already near bank full.
Cold air and snow follow
As temperatures fall into the 20s, wrap-around snow behind the departing low pressure system will hit early Monday and continue into Tuesday. With blustery northwest winds gusting to 30 mph, there will be considerable blowing, but a thin inch or so coating of snow could accumulate. Cold air will hold the remainder of the week, with a possibility of an accumulating snow reaching into northern Illinois Thursday.
Ice/snow further north
Freezing rain, 40 to 50 mph winds and heavy snow hit North Dakota and northern Minnesota Saturday downing power lines and creating near blizzard conditions. Additional snow will continue over these areas through Sunday.
What type of weather is most damaging or dangerous to our community?
Several answers are possible. Let’s first consider cost. Surprisingly, the chill of winter is the most costly (though not most damaging) aspect of Chicago’s weather because of the unavoidable expense of heating buildings. Regarding a specific kind of damaging weather, excessive rainfall and resultant flooding head the list. More generally, thunderstorms constitute our most costly weather events because they produce lightning, hail, high winds, flooding and tornadoes.
Finally, because weather-related highway accidents claim more lives and cause more injuries than other weather events, weather occurrences that contribute to auto accidents (rain, freezing rain, snow, fog) constitute the most dangerous kinds of weather.
Waves of heavy rain hit late Saturday into Sunday morning and are likely to spell doom for what remains of the city’s snow pack. An inch or more of snow has covered the ground at Midway Airport the past 28 days. The snowpack has managed to survive since just after Christmas even with arctic air a no-show the past 11 days.
A wet storm, likely to unleash an inch or more of wind-driven rain across much of the Chicago area as darkness settles in Saturday evening, spins up on the nose of the same powerful jet-stream-level wind max which has hammered the West with a week-long parade of vicious Pacific storms. The storm headed for Chicago develops over Arkansas Saturday, then lifts north into northern Illinois Sunday morning. Mild air is to rush into the area with the system — but will be masked for a time in lakeshore areas by strengthening southeast winds slicing off chilly 33-degree lake waters. Rising temperatures and humidities are likely to speed the snow cover’s demise Saturday night. A combination of the snowmelt and heavy downpours is likely to produce tremendous run-off, making standing water a good bet into Sunday.
The absence of snow isn’t likely to last long here. A realignment of atmospheric steering winds is to reinvigorate arctic air, chased into North America’s northernmost reaches the past two weeks. The chill is to crash southward over most of eastern North America over the next week. Slow cooling commences Sunday afternoon when temperatures are to back off low and mid 40-degree morning highs, settling into the mid-30s by nightfall. The cooling accelerates amid snow showers Monday when highs may fail to break out of the 20s. By Tuesday and Wednesday, frigid air will be back in full control with highs struggling to reach 20 Tuesday and the low 20s Thursday.
What happens next (mid and late week) will have to be monitored. Computer models suggest a potentially significant eastbound snow system could emerge from the Rockies midweek and swing into at least portions of the Midwest Thursday. The system has the potential of producing accumulating snow.
Parade of El Nino storms finally breaks out West
California residents, at the mercy all week of El Nino-enhanced storminess, have seen flooding rains and mudslides, hail with unusually energetic thunderstorms, a series of small but damaging tornadoes, and travel-inhibiting snows in the mountains. Los Gatos, south of San Francisco, topped late Friday rainfall tallies for the week registering 16.30″. Snowfall reached 90″ (7.5 feet) at Mammoth Lakes, Calif. — more snow that Chicago logged in its snowiest winter on record (89.7″ in 1978-79). The big snows weren’t limited to California. Flagstaff, Ariz., has been buried beneath 53.5″ of snow, and heavy snows have occurred in the mountains of Utah, Colorado and New Mexico. Precipitation winds down across the region this weekend.