Tomorrow and this weekend will be wonderful, but major changes are in store for us starting on Monday.
On that day, a weak front will come through, resulting in general (light) rain over western BC, Washington, and Oregon (see total through 5 AM Tuesday)
Another weak front will come through on Tuesday, so that total precipitation through Wednesday at 5 PM will be more impressive, with the mountains getting several inches (see below)
The forecast highs for Seattle Tac will be in the 70s for a few days, but once the fronts start moving in, we won't get out of the 60s....sorry.
But perhaps what is more interesting are the global changes that are occurring now. The Arctic is rapidly cooling, while the subtropics are staying warm, with the result being that a large north-south temperature difference is developing. This temperature difference is not uniform in space but concentrated in the midlatitudes, something illustrated by the temperatures forecast for October 19th at around 5000 ft (pressure of 850 hPa).
The development of a strong north-south temperature change (or gradient) results in the development of strong winds in the mid to upper troposphere (from 15,000 to 40,000 ft)....also known as the jet stream.
The upper-level wind forecast at 5 PM Monday is shown below at around 35,000 ft. A wavy jet stream is evident, with the strong winds (greater than 125 knots in red) stretching from Japan to California. A very good time to fly from Tokyo to San Francisco.
This jet stream is not going away, with a powerful jet stream extending east of Japan on Saturday, October 14th (see below).
Since storms and active weather are associated with the jet stream, you expect interesting weather on the West Coast....from rain to wind.
Enjoy!
Really appreciate and enjoy your explanations!
ReplyDeleteSure, meteorologists love to claim an association of weather with large scale temperature gradients and all that.
ReplyDeleteThose of us who have lived in the Pacific NW for a long time know that the upcoming cloudy weather is ACTUALLY caused by the fact that there is going to be something interesting to see in the sky. It HAS to be cloudy on October 14, because fate forbids Pacific NW residents from seeing cool phenomena like eclipses.
Actually, being more serious, it looks like the forecast for the morning of the 14th has no rain and just a thin, high altitude clouds. Maybe it will be worth making a pinhole projector with my kids so they can see it.
Very interesting! I've always wanted to know more about the jet stream. More, more! Recently I was talking with a former Navy pilot who described what it was like ejecting from a plane into a jet stream (the physical shock, plus bitter cold!) How cold are the stream? Fascinating.
ReplyDeleteBest time of the year here in the PNW
ReplyDeleteYears ago (20 ?) I had a ditch dug to run water and power to a small barn.
ReplyDeleteOne of these episodes hit and about when it cleared up, I caught the flu.
All winter, using 2x12 inch planks, we navigated the ditch to get to cars and into the house. By spring, the slumping meant lots of extra work completing the project.
I do not have any similar concern this fall, but I'd still like another two weeks. Can you conjure up a nice Indian Summer?
Cliff, as the Oct. 14 annular eclipse approaches, could you please provide guidance for those of us driving down to Oregon to catch it? Since maximum eclipse is pretty early at shortly after 9 am, it sounds like going east of the Cascades is probably the best bet for clear skies. Eugene would be more convenient, so if you think we have a prayer there it would be welcome news.
ReplyDeleteHey Cliff, didn't I read in an earlier post that we wouldn't see any more 80°+ days this year? Weather.com says that today we'll have a high of 83° here in Monroe!
ReplyDelete