The National Weather Service (NWS) has issued a Winter Storm Warning for significant snowfall for all of the Chicago area. The warning is in effect from 9:00 p.m. tonight through noon on Friday.

We have just participated in conference calls with both the Chicago and Milwaukee-Sullivan offices of the NWS, and want to make sure information about this storm system is shared broadly. Forecast models are in generally good agreement regarding the track and impact of this storm system, though minor variances in snow accumulation and timing of the start and end of snowfall for any specific location should be expected with any winter forecast. As always, we encourage you to pay attention to local media and weather information sources, such as the NWS webpage at http://www.crh.noaa.gov/lot/, for updated information throughout the storm.

A strong winter storm system is forecast to move into and across Illinois overnight tonight into Thursday morning. With entrenched cold air in place, the snow from this storm is expected to be lighter and fluffier than usual, leading to deeper snowfall from a relatively small amount of available atmospheric moisture. Across Lake County, there is a chance of snow this evening, with widespread heavier snow moving into the County around midnight. Snowfall rates will increase through the early morning hours, with accumulations of several inches of snow by Thursday morning. Periods of heavy snow are likely during the day on Thursday, tapering off into the evening, with accumulations of six to nine inches expected throughout the area. As the storm system moves to the east during the day Thursday, winds are forecast to increase from the north-northeast. This wind blowing across the waters of Lake Michigan will create "lake enhancement" of expected snow accumulation for areas along the lakefront and for several miles inland from the lake, with total accumulation along the lake of eight to twelve inches possible. Locally deeper snow amounts are possible, as bands of precipitation within the storm move across the area.

As the storm system moves on out of the area late Thursday, winds will shift to be coming from the northwest and increase, bringing colder air into the region. Winds gusting to 20-30 mph will cause considerable blowing and drifting of the light, dry snow, reducing visibilities to a half-mile or less at times late Thursday and Friday. Temperatures Friday night are forecast to drop to zero or below, with windchills near twenty below zero anticipated early Saturday morning.

Intense snowfall is possible during the morning commute Thursday, so please allow extra time and use caution with expected reduced visibility.

Lake County Emergency Management Agency does not anticipate providing any further update messages about this weather system.