There is a wonderful likelihood that western Washington goes to be hit by a serious lowland snow occasion.
And sure, the mountains will likely be buried as effectively.
It is feasible that some lowland areas will expertise greater than a foot of snow and February snow information will likely be damaged at some places. Can I completely assure this? No. Is a serious occasion extremely possible? Yes.
A giant concern yesterday was the substantial distinction within the snow forecasts of the American and European Center fashions, with the European model–generally the extra correct one– going for rather more snow over western Washington.
Overnight the American mannequin has moved in the direction of the European resolution.
Let me present you the amassed snowfall over time from the European mannequin. And let me stress, snow depth will likely be LESS than whole snowfall (what falls out of the sky), as a result of melting, settling and compaction, and different causes.
The snow will start on Thursday. The snowfall whole by way of 10 PM Thursday exhibits important snow from north Seattle to Olympia, with the best quantities within the south Sound
And the snow deepens by 10 PM Friday, with roughly a foot within the south Sound. Huge quantities within the Cascades. Too heat for snow within the Willamette Valley and the Oregon coast.
More snow hits on Saturday, with snow extending to Portland, cooled by air coming by way of the Columbia Gorge. Nearly a foot as much as central Seattle. Just loopy within the mountains.
As I’ve advised you a lot occasions, by no means take a look at a single forecast. One wants to contemplate uncertainty, and ensembles of many forecasts assist quantify it. The 51 member European Center ensemble for snowfall at SeaTac Airiport is proven beneath, the highest panel having 51 stripes, one for every forecast. Most members are going for a serious snowstorm…maybe three or 5 out of the 51 should not. Nothing is definite. You should cope with chances.
Importantly, the U.S. GFS mannequin ensembles (solely 21 members) appears to be like related, however with the next p.c of the members have much less snow.
The excessive decision U.S. GFS forecast (blue line) goes for ALMOST 20 inches of snow by late Monday. Unbelievable. And right here is the U.S. GFS snowfall forecast by way of 10 PM Sunday. 24 inches in Tacoma, 20 inches in Seattle. The mountains would most likely be impassable if this forecast comes true.
And there are subtleties that I have not talked about. Strong easterly winds on the western slopes of the Cascades that ought to reduce snowfall between the Sound and the Cascades (as a result of sinking air works towards precipitation). The unusually chilly air east of the Cascade crest. And rather more.
I’ll most likely do a particular podcast about this occasion tomorrow (Wednesday). There are quite a lot of transferring items with this occasion and thus uncertainty…however at this level a serious occasion seems to be within the playing cards.