The Chicago area’s first significant snowfall of the year has arrived!
Snow began in the pre-dawn hours and will continue to fall into the afternoon hours.
My WGN meteorological colleague Paul Merzlock reports nearly 4″ down on Joliet’s west side as Wednesday morning dawned. A number of other locations are at 3″ and counting as the snow continues to fall.
Heavier 6 a.m. snowfall reports from across the greater Chicago area from COCRAHS volunteer observers and my WGN colleagues: (Note: The distance in miles that each observation location is located from the indicated cities is included right after each snowfall report:
3.5″ 0.8SE Elmhurst
3.4″ 0.8WNW Wheaton
3″ 1.8SE New Lenox
3″ 3.1N Carbon Hill
3″ 3.5 ESE Aurora
2.9″ 1.5SW Morris
2.8″ 1.5NE North Aurora
2.8″ 1.3SW Palos Park
2.8″ 0.7NNE Homer Glen
2.8″ 4.8ENE Gary, Indiana
2.8″ 4.3SW Valparaiso, Indiana
2.5″ 0.1ESE Homewood
2.4″ 1.4WSW Kankakee
2.4″ 0.3NNE Mt. Prospect
2.4″ 0.4NNE Harwood Heights
2.4″ Oak Forest
2″ 2.4SE Hobart, IN
2″ Arlington Heights
2″ 5.9S DeMotte, IN
I’ve included only some of the heavier reports. For a complete list of COCORAHS observer reports, here’s a link.
Visibilities also dropping
Visibility is a great proxy for snowfall intensity. When visibilities drop to fractions of a mile, the snow’s coming down quite heavily. In fact, visibility is a parameter used by meteorologists to identify “light” versus “moderate” and “heavy” snow intensity.
Here are maps of visibilities at 9am CST Wednesday morning.
Here are the snow intensities used to delineate between “light”, “moderate” and ” heavy” snow intensity: “The standard relationship between snowfall intensity and visibility used by many national weather services (1/4 mile or less visibility corresponds to heavy snowfall intensity, between 5/16 and 5/8 mile corresponds to moderate intensity, and greater than 5/8 mile corresponds to light intensity)”