Update: 12/19/13, 4:15PM: The Winter Storm Watch issued this morning by the National Weather Service has been scaled back to a Winter Weather Advisory. The thinking now is 1-3 inches for the Puget Sound lowlands, with higher accumulations away east and north of Seattle. Other details in the story below still in effect.
The thing about the National Weather Service is, it’s their job to warn us when there’s a chance of inclement weather. Does that mean it will always happen? No. But if it does and they DIDN’T warn us, they’d never hear the end of it.
So they warn even when there’s just a chance of snow. Because let’s face it, people in Western Washington aren’t the best at driving in snow or dealing with it. Even a little bit can snarl a light commute day.
In the case of tomorrow, a Winter Weather Advisory has been issued and runs from 10PM tonight (Thursday, December 19th) through Friday afternoon. This means there’s a risk of a snow event – not that snow is imminent.
In the case of this latest snow forecast, it appears likely the snow will start very early Friday morning, December 20, 2013 (in the 1-4AM time range) and right in time for the morning commute.
The snow is predicted to change to rain by afternoon since this is warmer air overrunning cold air snow event. While that warm air is beating up on the cold air, it snows for a while, then changes to rain and makes a mess of the pretty snow. Not my favorite type of snow event by any means.
The snow totals are predicted to be higher east of Seattle and closer to the west slopes of the Cascade Mountains – so the Snoqualmie Valley. How much snow exactly falls remains to be seen. As of this morning, the KOMO weather forecasters are saying 1-4 inches north and east of Puget Sound.
Warning! This could all change as the weather system nears Washington. Forecasters are very certain it will start as snow, but then it gets unpredictable. The National Weather Service says snow amounts are very uncertain, as it really isn’t that cold today the southerly winds usually warm the air quickly. Cliff Mass, weather blog guru and University of Washington Atmospheric Science professor, said the probability of snow during the morning commute is “very high.”
The UW snow total predictor model shows more snow for the Snoqualmie Valley than the 0-2″ predicted for Seattle, and according to Mass, predicted snow totals for the lowlands can easily be off by 50%.
Alert! Snoqualmie Valley Schools have an early release scheduled for Friday, December 20th, which also signals the start of winter break. As it’s already a shortened day, the district may be more inclined to cancel school rather than run more than a 1-hour late start. If your kids have school things to bring home for break, it could be a good idea to bring them home today – just as precaution.
Note! As merely forecasting snow, without even tackling predicted amounts, is tricky in the Puget Sound area, chances are we won’t know everything until later tonight – when and IF it actually starts snowing.