Snow coming! If it isn’t gobbled up..

Snoqualmie Valley/ central Cascade foothills

Thursday PM-Friday AM:

Snow potential – models are diverging for the above time period, but this isn’t the main event.  The NAM model has a Low making landfall even further south (Lincoln City-Eugene OR swatch) than what was projected in earlier model runs yesterday.  If NAM wins out, we remain bone dry.  If the Low path follows the Euro model projection, we’ll see a dusting-2″ in the central foothills. Snow level expected near sea level with the cold air so your altitude matters less than during wet snow events.  Snow totals we forecast are smaller than advertised by the media due to the gap winds expected to eat/evaporate some of the falling snow.

Winds – models are converging on gap winds from the east to begin Thursday late AM/early PM to reach peak gust potential (~30-40 mph) from 6pm to midnight and remain gusty through the day on Friday.

Friday PM-Saturday AM:

Bigger snow (and Wind) potential – Friday PM through Saturday

There’s currently wider consensus from models that without any wind we’d be looking at 5-10″ of snowfall Friday PM through Saturday.  So the moisture should be there, however, from about 7pm Friday to 7am Saturday the E-W pressure gradient looks to tighten and really get the foothills gusting (50+ mph is certainly possible).  How much snow these winds will ultimately eat can be difficult to forecast, but based on experience we’ll go with 50% of the above totals for now.  That being, I’d expect 2-5″ of snow from Friday evening through Saturday.

Future model runs can and often will throw a wrench into all of this.  

We’ll continue to update as we get closer.

[Originally published at Snoqualmie Weather blog. During active weather, follow more frequent updates @snoqualmiewx or on Facebook]

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