ORIGINAL 12:48 PM REPORT: Just in from SDOT:

The Seattle Department of Transportation (SDOT) is carefully monitoring weather forecasts for Seattle and planning for snow and ice response accordingly. The forecast is for temperatures just above freezing overnight with up to one-half inch of wet snow possible, and an additional one inch of snow possible tomorrow (Wednesday) morning.
 
After 10 p.m. tonight SDOT crews will proactively apply salt brine in roadway areas where frost or black ice is prone to develop, especially on bridges and other elevated structures around the city.
 
Starting at 4 a.m. tomorrow morning (Wednesday), SDOT spreader trucks will be prepositioned throughout the city, ready to spread rock salt on major arterial streets (primary snow routes, Levels 1 and 2) for the morning commute if conditions warrant.
 
The snow plan calls for plowing when there is more than one inch of accumulated snow on the roadway, which is not in the forecast at this time.
 
SDOT will continue to monitor the weather conditions carefully and respond accordingly.
 
For more information on Seattle’s winter weather response plan and to view a map of snow routes, please see SDOT’s website.

2:07 PM NOTE: Meantime, the National Weather Service’s “forecast discussion” is still downplaying the likelihood of some snow – another update should be out within the next two hours; whatever happens, they say, would be overnight into the early morning. And WSDOT has announced it’ll open the I-5 express lanes southbound at midnight, just in case.

ADDED 3 PM: Metro has weighed in:

With snow showers in the forecast for Wednesday morning, King County Metro Transit is urging bus riders to prepare by making sure they are signed up for Transit Alerts and that they know the snow routing for the buses they will ride tomorrow.

Then before traveling, riders should check kingcounty.gov/metro/snow for the most current status of Metro service. Updates to the online information will begin at 4 a.m. each morning.

Remember, Metro is operating with a reduced schedule this week, which means some commuter and school-oriented routes do not operate, and other routes have individual trips canceled. This is indicated by an “H” in the timetables.

Current weather forecasts indicate if snow falls Tuesday night into Wednesday morning in the lower elevations of King County, it should be mostly in the form of snow showers with no significant accumulations. But, the snow could be heavier at higher areas in east King County or if a convergence zone sets up inside the county. Bus operations could change rapidly.

We’ll be on early/late watch too, as always, including 1st word from Metro in the morning re: their plans.