June 19, 2021

The sun is great… but 5 weeks?

This weather has been stupendous. Amazing. Incredible.

But I admit to being a little sceptical and a little worried.

As you can see here, in July and August we have had only 6 days below 25C.

But that doesn’t really tell the story. How can we have so much perfectly sunny weather over such a long period of time. My theory is it is down to a weak and nearly non existent Jetstream.

San Francisco State University has archived Jetstream analyses going back to 2010.

I have put together the animations for July/August 2010 and July/August 2013. This is a combination of satellite imagery and jetstream analysis (in yellow). You should notice that 2010 has a lot more yellow streaming over and around us, where as in 2013 it is broken up and infrequent.

What I believe it shows is the jetstream in 2010 (which was somewhat cooler but much more variable than 2013) featured a straighter, more consistently present jet stream. Whereas 2013 has featured a kinked, and almost non-existent jet stream. This is only one years comparison of course. So we should take this with a big grain of salt.

That’s my theory. I’m sticking with it for now. 🙂 We’ll see what August will hold. For now, it doesn’t look like it’s going to be much different. It sure would be nice to get a little rain.

5 thoughts on “The sun is great… but 5 weeks?

  1. I would like sun at least six days out of seven with rain falling between the hours of midnight and four, gently, every other day. Not happening? Well, I could make like all the media weather types and moan and complain, or take responsibility for it, or not, or tell my viewers/listeners that “I” am keeping a cloud or two in MY forecast. Too much emotional content where none belongs! I like the maps and explanations here. Keep it up.

  2. Good theory Chris, I’ll go with that! But WHY is the jet stream weak this summer, inquiring minds want to know?

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