The National Weather Service has upgraded Lake County to a winter storm warning as they warn that parts of the county could see nearly a foot of snow Sunday into Monday.
The National Weather Service (NWS) initially issued a winter storm watch for Lake County early Sunday morning, in effect from Sunday evening into Monday.
The watch was upgraded Sunday afternoon to a winter storm warning, which will be in effect from 9 p.m. Sunday to 6 a.m. Monday.
The warning says that dangerous to impossible travel conditions will develop across parts of Lake County due to intense lake effect snow.
Snow rates in excess of three inches per hour and localized snow accumulations in excess of 10 inches are possible, the NWS said.
Forecasters also warned of possible northerly wind gusts in excess of 30 mph.
The strong wind gusts may lead to greatly reduced visibility, especially near the Lake Michigan shoreline.
“Lake effect snow is often very localized, with conditions varying from safe to dangerous across just a few miles,” the watch said.
The highest snow totals if lake effect snow impacts Lake County would occur near and east of Interstate 94, with considerably less snow on the western side of the county.
The NWS also issued a winter storm warning for Chicago and Cook County, warning of snow rates in excess of three inches per hour.
The warning said localized total snow accumulations of 12-18 inches with northerly wind gusts in excess of 30 mph are expected.
Timing is expected from 9 p.m. Sunday to 12 p.m. Monday. “Snow totals in the Winter Storm Warning area may vary considerably from one location to the next.”
The NWS said lake effect snow will start between 9 p.m. and 12 a.m. along the Lake Michigan shoreline and quickly spread inland.
“While the intensity will be greatest near Lake Michigan, the first burst of lake effect snow will penetrate far inland reaching as far west as I-39 and as far south as IL-9,” the weather service said.
The NWS said that behind the leading burst of snow, lake effect snow bands will refocus near Interstate 55 or Interstate 57 in Illinois on Monday morning and then shift eastward into northwestern Indiana on Monday afternoon.
“Lake effect snow is a very localized phenomenon. Beneath the snow bands, it will be snowing VERY hard with snow rates locally in excess of 3″ an hour leading to dangerous to impossible travel conditions. Meanwhile, a few miles away, it may not be snowing at all,” the NWS said.
Motorists should consider delaying travel where the lake effect snow is ongoing, forecasters said.
Lake County and McHenry County saw the first snow of the season on Saturday evening into Sunday morning with wet snowfall.