WINTER WEATHER UPDATE

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GFS Update 10:40pm
Tonight’s GFS paints a very different picture than the NAM. It has a QPF 0.35 inches water and a colder profile, maintaining snow through 10am. That would amount to 3-4 inches of snow before a changeover to sleet later in the morning.

I’m staying with the NAM forecast described below, but this GFS difference makes this a low confidence forecast.

Things continue to evolve with the forecast. Tonight’s NAM and NBM data just became available.  QPF values of less than 0.08 from now until the changeover to sleet about 7 AM is expected to limit snow accumulations to a coating or less than 1 inch.

Temperatures at the surface will be marginally cold enough to prevent much if any accumulation in the city proper, except on some surfaces.

North and west of the city, temperatures are forecast to be 31-32, but the increase in precipitation rate about 7-8 AM will correspond with the changeover to sleet and some freezing rain.  Some accumulation of sleet is possible.  Larger accumulations of sleet and snow will be an issue primarily in the far northwest suburbs. 

This will be a messy storm, but most of the precipitation will eventually fall as rain in most areas.. A mix of precipitation is possible until mid to late morning, then rain.

The GFS will be available in an hour or so. I’ll update if the GFS is significantly different.