Our wild ride of a week continues. I wouldn't blame you if you thought I was repeating myself from earlier this week...but there's a chance of snow in the forecast tonight (Thursday night) into early tomorrow (Friday) morning, and again Friday night into Saturday morning. It's nowhere near a slam dunk - in other words, don't get your hopes up too high (now I am repeating myself!) - but it's there.
The brunt of the rain has been focused to our south today, leaving us with a dry morning - great conditions for crews to clean up and restore power from last night's wind storm! But that also opened the door for some cooler air higher up in the atmosphere to move back into the region. As of this evening, the rain has already begun falling again, and will stick around through tomorrow afternoon. But that's not what you're here to read about...
Snow is incredibly hard to predict in the PNW in general. This is one of those "borderline" events, with a pretty wide difference between the "boom" and "bust" potential. On the one hand, we should have a good amount of precip to work with tonight! On the other hand, temps aren't supposed to get much below freezing. But, if the precip is falling heavily enough, it can bring some of that colder air aloft down with it, and cool the air temps here at the surface by a few degrees...which could be the difference between cold rain, a rain/snow mix, or just plain snow. Best guess at timing the transition from rain to mix/snow is sometime in the early morning hours, lasting thru sometime tomorrow mid-morning...meaning either when the precip shuts off, or temps warm to above freezing (or both).
On the "bust" side: no snow, all rain, temps stay in the mid-30s overnight. On the "boom" side: we drop to near or slightly below freezing, and end up with a slushy inch-ish of accumulation - mainly on grasses though, the roads are just too warm to accumulate very much. Best guess, somewhere in the middle: lawns and windshields have some flakes on them by tomorrow morning. (Tomorrow's a day off from school anyways...sorry kiddos!) Regardless, it probably won't stick around too long either.
Another way of looking at it - snow levels are forecast to drop to somewhere near 500-1000 feet overnight tonight. For reference: most of Sammamish is roughly 300-500 feet in elevation, with some of the higher hills getting closer to 600 feet. The "lower" Issaquah Highlands (around Swedish and Grand Ridge Plaza) sit around 400-500, while the "upper" Issaquah Highlands (around Grand Ridge Elementary and the Village Green) are at 700-900 feet - Harrison and Grand Ridge Drive are even higher!
One more interesting tidbit: the Plateau could also be near the east/west dividing line - better chances to our east, higher up in the foothills; lower chances to our west, towards Bellevue (aside from the higher hills south of I-90) and Seattle.
At this point, all we can do is wait and see. I'll be back tomorrow with another update - and a look at the weekend and the early part of next week!