I will start today with an interesting fact: from around 11:45pm Wednesday to around 10:27am today, the visibility at SeaTac has not been more than 5mi., with most of it 2mi. or less. Just think about that a little bit.
Thursday – High 51, Low 48 (yes you read that right); Foggy all day. Some places may have cleared up a little bit, but the fog kept the high down, and the low up.
Friday – High 54; The relative humidity was pretty high this morning, so the extra moisture started to mist down, and actually registered a very small amount of precipitation in places. Made things a little slippery depending on the surface. Interestingly enough, the fog cleared up to a 10mi visibility, but the moisture only went up, giving us a nice, low, gray ceiling. Is this the sign that things are finally going to clear up?
With the updated models, it looks like the little upper level low will actually pass over us as it moves to the south on Saturday. This will get the ball rolling for clearing up the fog, but the big player will be the actual trough that moves down from Canada Sunday morning. What this will do is bring in some dry northerly winds from Canada and start to displace that moisture, thus getting rid of our stagnant layer of air. Hopefully this will be the end of the fog!
For once, there is activity on the precipitation model, but I won’t put it here because it all actually misses us. Two decently sized systems move south just off the coast and over Eastern Washington. So I still forecast no rain for the weekend. As for cloud cover, it’s going to get better. The models are still being a little disagreeable with the fog/clouds, so here’s what I think is going to happen: Saturday morning, we’ll have fog. We may get some drizzle here and there like we did this morning, but the fog shouldn’t be as dense as it has been. It should start clearing up later in the day, but it will still be cloudy. The fog will return Saturday night/Sunday morning, but should be more of the patchy nature. It’ll then turn cloudy, and by the afternoon it’ll hopefully be sunny again!
Winds for tomorrow will be much of the same as we have see: almost non existent. However, when the trough moves in on Sunday, we should get our usual fall winds back. They will be northerly, so expect some cool brisk breezes. Also expect some fairly stronger winds over the water, mainly in the 15kt to 25kt range.
The temperatures are still a little iffy for Saturday. I think I’m going to play it on the safe side, and go with mid 50s for most everyone. The models think higher, but I think that all pertains to if the clouds break, which may not happen for most people. Lows will be in the high 40s. Now you would think Sunday will see a bit of a warm up with the departure of the fog and clouds. Well, you have to take into account the winds we will be getting…the northerly winds…coming from a cold Canada. These winds will be bringing down some cool air, so we should actually see some of the same temperatures as we will Saturday. I’ll go mid to high 50s, and depending on when the clouds break, the northern areas may get close to 60, although it’s doubtful. Lows will be in the low-mid 40s (with the departure of our insulating cloud/fog blanket, the ground heat will escape, cooling down the lows).
TL;DR: Foggy morning and cloudy afternoon on Saturday, patchy fog and clouds clearing up to mostly clear skies Sunday!