More snow fell in the city Tuesday than has fallen over the past 4 Marches COMBINED! The day's snowfall exceeded the "normal" total for the entire month of March and
Tuesday's preliminary 9.1" tally at O'Hare and the 9.0 inches reported at Midway rank as the city's heaviest calendar day snowfall in a March in 59 years---since the 11.5" fell March 2, 1959.
Snow Tuesday fell for more than 16 hours across the Chicago area. It started at 5:38 am at Midway and 5:35 am at O'Hare and, for nine of the 16 hours, fell heavily at rates of 1 to 2 inches per hour, slashing visibilities to one-half mile or less at virtually all observation sites across the greater Chicago area.
Quarter-mile and lower visibilities, indicating especially heavy snowfall---what members of the meteorological profession refer to as "S+"---reached, at more than one point Tuesday afternoon, into every corner of the greater Chicago area.
The area reporting fractions- of a mile visibilities in the day's heavy snow spanned an impressive swath of real-estate, extending from northwest Indiana across much of northern Illinois and into portions of southern Wisconsin simultaneously over many hours!
It's been 59 years since a March snowstorm generated as much or more snow in a single day as Tuesday's. On March 2, 1959, 11.5" fell here---but that's the last time a higher calendar day March snow tally has occurred in Chicago.
Not only were Tuesday's accumulations higher than the normal values FOR THE ENTIRE MONTH OF MARCH (5.6"), they also blew past the COMBINED SNOWFALL of the past four Marches here which together totaled 5.2".
Late Tuesday’s preliminary storm totals of 9.0" at Midway and 9.1" at O'Hare placed the system among the four heaviest calendar day snow-producers over the 128 year term of Chicago's snow record. It's likely the final storm tallies may end up bit higher since the snow was still coming down lightly when the measurements were made late Tuesday.
Storm's heaviest snow tallies across the area approached one foot!
Reports of even heavier snowfalls than those observed in the city proper abound. Among the heavier totals Tuesday was the 11" tally at LaGrange, the 10.1" total at Cortland in DeKalb County, and the 10" accumulations at Elburn, Oregon, IL, Michigan City and Hobart, both in Indiana.
Among the cities south of Chicago to record their biggest single snowfall of the 2012-13 season Tuesday was Valparaiso, IN, with its 7.5" accumulation; 7.6" at Beecher; 7.3" at Whiting IN and the more than 4" which fell at Renssalaer, IN.
Strong winds produced blowing and drifting in open areas late Tuesday night.
Snowstorm’s next target: Sections of the East Coast
The system is now off to the East Coast and western Atlantic where the National Weather Service's impressive new suite of super-ensemble winter precip guidance products out of its National Centers for Environmental Prediction (NCEP) suggest significant snows may occur from near Washington north to Philadelphia, New York and Boston.