Sunday, October 17, 2010

Pacific Storm Train Ramping Up?

October 17, 2010
Hey everybody, thanks for continuing to read my blog, it means a lot. I know I've not been writing for a while, that generally means I just have a bunch of homework to do, as was the case this past week. I still have a ton of homework to do, but I thought I'd write a little update on what we can expect weather-wise the coming week and beyond. Just remember that when I'm not writing, it's because I'm busy, not because I've forgotten about the blog or suddenly lost interest in weather. You just have to straighten out your priorities, you know?

This is an image of the jetstream over our area (more specifically, the winds at the 300 millibar level in the atmosphere). As you can see, it is aimed right at us, and when we have the jet stream aimed right at us, the "Pacific Storm Train" occurs. If you remember either January or November 2006, it is easy to see why they have given it this name. Once the "door is open" (that is, there is no blocking ridge of high pressure and the jet stream is pointed directly at us), storm after storm after storm can hit the Pacific Northwest. These storms are usually strong and progressive, which means that they can bring a lot of wind, rain, and snow for several hours, then they will pass, only to have another storm arrive several hours later. Flooding is generally not a huge issue with this type of zonal flow because snow levels are lower than if the jet stream had a more southerly component and the periods of rain are usually shorter with more breaks between them. However, we can still get flooding rains, don't misinterpret what I am saying. They are just more likely in a setup that is not as fast or progressive and where the jet stream dips down towards Hawaii and is then shunted in our direction by a ridge of high pressure to our south. Pineapple Express (flooding) events are often triggered by a pattern in the tropics called the Madden-Julian Oscillation, but I will talk about that at a different time.

In the meantime, take a look at some of the forecast images from the GFS model that show a potential windstorm about a week from now and a very strong jet. Normally I would just discount this individual windstorm and say we are just going to be in an active pattern, but the models have been very consistent with this individual storm. And yes, I finally found out how to make everything clickable, so now you can actually get a good idea of what is going on because you will be able to see the pictures at the right size! Thanks for looking and savor your sunshine while it lasts folks because it looks like we are going to get stormy.

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