September 26, 2009

Nice Weekend and then Downhill a bit

I returned on Friday from a workshop in Boulder, Colorado on developing the next generation weather prediction system. Such a system would be essentially probabilistic in nature---rather than giving a single answer as we do today. It really doesn't make sense to say the high temp at Seattle in seven days will be 67F--there is substantial uncertainty in the answer and that uncertainty depends on the situation. My field is developing the technologies to provide uncertainty information--including probabilities of much more than precipitation. This is a major revolution in the way we do business. But is the population ready for this? Will they accept and use it?

While I was in Boulder it snowed! On Wednesday, there were snow flakes in the air, with temperatures dropping into the upper 30sF. Being over 5000 ft and open to the cold air to the north really helps.

This weekend will be moderate in temperature and very nice here in the NW. Look at the latest satellite image (above). You will notice some residual low clouds from a dissipating front that moved through this morning. But skies will clear and temps should rise into the mid and upper 60s for most of the west.

Tomorrow will be even nicer. High pressure (ridging) will develop aloft and its surface manifestation will be high pressure to our east (figure). You know what that implies...offshore flow and compressional warming as air descends the western slopes of the Cascades (see figure). Our friend the thermal trough will be back. So tomorrow will be sunny with many temps rising into the upper 60s and lower 70s.

Monday really won't be too bad. A week front will approach...but will not arrive until late in the day. Thus, most of Monday will be dry, but with increasing clouds and chance of showers very late in the day.

Tuesday should be cooler and showery...but really nothing to write home about.

So enjoy a very nice weekend....


  1. Too bad we are planning to go hiking Monday and Tuesday. Sounds like the night in the mountains might be a wet one. Are there areas (not too far from Seattle) that are drier than others in this situation?

  2. will be much drier east of the Cascade crest. Monday will be fine in the Cascades...

  3. Back to Fall weather, with gratitude Cliff Mass!

    When will be the first frost?
    Snow this year?
    Will it be like last December?

    All rhetorical questions, or not...

  4. Cliff, have you seen this really wonderful tribute to Carl Sagan?

  5. Oh my, you know how subjective that post is? Yes, it's your blog, so subjectiveness is okay, but I really wish that meteorologists who claim they like weather wouldn't try to continue to brainwash the public into not liking it. By saying it's nice when very little weather is existing is doing just that. And you know, there are lots of people who are going to be so much more comfortable, finally, when the weather starts going "downhill" (whatever that means).

  6. "...very little weather is existing..."

    I'm pretty sure (unless the sun just exploded and blew the atmosphere off the earth) that there's always the same amount of weather. Sometimes it's dramatic, other times benign, but it's always weather. I think it's awfully hypocritical of you to dismiss the preferences of the majority of us that prefer warm, sunny, and dry conditions and claim that we "hate weather" when I think no such opinion has been stated, while you clearly do "hate weather" and troll around here every chance you get.

  7. life-

    you can't quantify weather. sunny, rainy, windy.. it's all weather. 99% of us prefer warm, sunny weather so the "biased" media tends to cater to that opinion. Why do we like warmth and sunshine? Because 99% of us like to enjoy outdoor activities in comfort.

  8. I like enjoying outdoor activities in comfort too - so I guess I'm part of that 99%. But I (and many others, probably at least 10% of the population) are much more comfortable when it's cooler. People are different.

    FYI for some people... the sun is not weather. Weather is what happens in our atmosphere. If the sun was in our atmosphere, we'd all be dead. :)

  9. Joseph, if I had a blog, would you visit? I would talk a lot about the weather and meteorology but would not offer any subjective opinions either way.

  10. Thanks for your reality check, Andy.

    Solar heated air is weather. Weather is the dynamics of the atmosphere. No weather = vacuum.

    Language is a set of socially agreed upon terms describing a consensual reality. Contradicting agreed upon language is generally considered anti-social.

    Most people will agree we have had great weather this summer and that the great weather is about to change to a less comfortable climatological norm.

  11. Checking constantly for rain for the last two weeks. This new weather system is not “bad” or “downhill,” since I'm very happy to see the seasons get back into the wet groove. Here's to warm fires, puddle stomping, and fungi picking!

  12. Yay Trever!! Some people think we're "anti-social." :)

  13. Cliff, I'm really excited to hear about the conference you attended. I was only recently introduced to Probcast and it seems like a great first step to getting rid of the the singular numeric high or low prediction 5 days out. I end up wading through the forecast discussion trying to figure out just how much confidence the forecasters have in their predictions. It would be of great advantage if this were reflected in the forecast.

    Thanks, Tom.

  14. Yes Cliff. Interesting to here about the conference. By the way have you ever heard of flow 3d. I am using it on fire dynamics (how fire moves around structures in a wildfire). I was wondering how it might be used in moisture simulation around mountains or even imported dem maps of the pacific northwest.

  15. Autumn is here in Fremont. Break out the kites. But some memory of mine says we're entering the Northwest fog season. I remember so many Oct/Nov foggy mornings where I felt trapped in a big ping pong ball all day... So Dr Mass, do we have an official fog season here? (May be a future weblog topic.)


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