Fri-Sat, dec 11-12th Snow Event Update #1

(9:45PM - 12/9/20) A storm system will move through the region Friday through Saturday, bringing the chance for accumulating snow to portions of Northern Illinois Friday morning through Saturday night.

Summary...
A storm system will move through the region Friday through Saturday, bringing the chance for accumulating snow to portions of Northern Illinois Friday morning through Saturday night. After having some disagreement in prior days regarding track and strength of the storm system in question, model guidance is now in fairly good overall agreement regarding this event. A developing storm system is expected to eject out from the Plains on Friday, tracking northeastward, and into the Great Lakes on Saturday. Marginal cold air will be in place, and when combined with the favorable storm track, will lead to a swath of accumulating snow across portions of the region and state.

Forecast...
Precipitation will first push into Northern Illinois Friday morning, in the form of rain. As the storm system further develops and some colder air filters in, rain will turn to rain/snow or all snow for areas of Northern Illinois closer to the Illinois/Wisconsin border Snow will then continue in varying intensity for Northern Illinois near the Illinois/Wisconsin border through early Saturday night. Further south, as the storm system wraps up and passes the area, enough cold air will wrap in, allowing for rain to change over to rain/snow or all snow further south across Northern Illinois, generally along and north of I-88...From Saturday morning through early Saturday night.

Final snowfall totals in the main axis will generally range from 1-3", however within main axis a corridor of 2-5" snowfall totals are possible. Temperatures are expected to be marginal during this event, and when combined with recent mild temperatures, will lead to some melting as the snow falls...in addition, colder surfaces are likely to receive the highest accumulation.

​Below is the snowfall forecast for this event.

JP