CHICAGO --The National Weather Service has extended the Winter Storm Warning for the Chicago area.
The warning goes in effect this evening at 9 p.m. and will last until 6 a.m. Monday.
An impressive 9 to 13″ of snow is on the way–in some locations there may be more–and it’s to be spread over an impressive 30-36 hour period starting this evening and continuing Sunday and Sunday night during which “NE” winds are to strengthen. The 35 mph gusts due by Sunday afternoon and evening are to send 12 ft. waves into the Wisconsin, Illinois and far northwest Indiana shorelines.
The morning Saturday model suite is now in and produces storm guidance which is a virtual carbon copy of preceding forecast cycles. Continuity reinforces confidence in any storm forecast. The packed isobars in the surface forecast panel at the top of this post, portray the driving force between the wind field projected to develop formidably this storm system. The tight, wind-generating pressure gradient predicted is to occur between a sprawling 1040 mb (30.71″) Canadian high pressure in the Dakotas and the storm system’s 1008 mb center predicted to march across downstate Illinois and Indiana.
Here are some of this storm’s predicted features which support the notion it is to be a significant one. This meteogram offers a graphic portrayal of this storm’s extensive moisture field over time. It depicts an atmosphere which is to be fully saturated and begin snowing Saturday evening–snowfall which may vary in intensity but is expected to continue until just before 6am Monday morning. (A lake-effect moisture plume may be flirting with the Chicago or northeast Illinois are into Monday morning and that could keep some snow going in shoreline areas in the early Monday morning period. That’s quite a period of snowfall!