Friday, January 21, 2011
This has to be a quick post, as I am doing tons of hw (I am SO excited for the semester to be over!) but it is mainly just an update to let you know I am still blogging. Although we have a couple flood watches now, it will get drier over the next week or so and possibly stay that way for quite some time as a blocking ridge of high pressure rests off of our coast. We should see partly cloudy skies and a few showers from time to time as weak storms attempt to break through the ridge. No snow in Seattle anytime soon.
I told you that would be quick! Three minutes to be exact :)
Wednesday, January 12, 2011
Hey everybody, I am going to try and update this blog more often, even if it is only for a little while. We saw more snow than what was expected last night, although not that much more. The reason? The models scoured out the cold air too quickly. This is something I have seen with the last three of these overrunning events. It takes a significant amount of energy to melt snow to rain, and it seems as though the models underestimate this amount. They seem to simply "swap in" milder, marine air without paying attention to the latent heat of fusion (energy required to melt ice). Next time, I will add in a note and forecast the snow to end a little later than what is forecast on the models. However, there are also times when the snow has ended and switched over to rain sooner than predicted. Just goes to show how hard it is to forecast in the Pacific Northwest!
Looking ahead, we have a fairly active week in front of us, with several moderately strong storms passing to the north of our region. The latest GFS model has a strong zonal flow over Oregon, which would give Oregon lots of rain and the mountains lots of snow. We will be mild, with highs getting up into the upper 40s/low 50s.
That's all for now, thanks for reading!
Tuesday, January 11, 2011
Sunday, January 9, 2011
Sunday, January 9, 2011
As I try to memorize this stupid... er... wonderful passage, I am faced with an utterly more important question. Will we, or will we not, see a major snowstorm?
And the answer is... I really have no clue. But it is looking less likely.
One thing meteorologists look for in models is run to run consistency and trends. The previous models, especially the one Americans use the most, the GFS, were all very, very consistent in bringing a historical snow event to at least some part of the Pacific Northwest. However, now all the models have shifted the storm track much further north. This means we would be on the warm side of the storm. As you can see in the map above, the low pressure center is now approximately over Ucluelet (Southern Vancouver Island). This would mean that instead of getting a cool northerly wind to cause snow to the area, we would get a warmer southerly wind that would change it all to rain. We may see 1-3 inches before the switchover, but compared to what the models were showing before, this is nothing.
But there is a little bit of good news. I did save money on my car insur...
Just kidding. But really, there is some good news. Models before had the storm even further north, up by the northern tip of Vancouver Island. Now, it is about 200 more miles south. If it is 200 miles more south, we WILL see a snowstorm of historic proportions. Precipitation is not the issue. The temperature is.
And the mountains will see tons of snow regardless. Here is a 24 hour snowfall period forecast from 4 P.M. Tuesday to 4 P.M. Wednesday. The storm is also expected to get here sooner, Wednesday instead of Thursday.
Whether tis nobler to have a storm come in to our south
Or to suffer the travesties of one to our north
Ok I give up. Gotta study.
But listen closely. If this storm does come to our south, we will see a foot, perhaps more, of snow. So now is the time to prepare.
You stay classy, planet Earth.
Friday, January 7, 2011
Thankfully the weather has been fairly benign lately, and there hasn't been much to talk about. But then I woke up this morning, and I saw this.
Now, I don't want everybody to get excited. There are often events like this that show up on the models and everybody gets super excited only to have snow not fall at all. Out of three models, two are showing significant snow, and one is showing a snowy transition to rain. I'd say we have a pretty good chance of getting some snow. The question is if we get a switchover to rain, or if it stays all snow and we just get walloped (like above). First, you need to have cold air in place. Cold air will start to filter into the area this weekend, with highs in the mid 30s or so. While I would like to have the air be colder, it is cold enough for snow (air can be above freezing and the precipitation can still be snow, particularly if the air is dry or the precipitation is heavy). Now, take a look at the graphic below.
It is important to understand why we might have such a big snow storm, and what ingredients are needed to come together to deliver a potentially historical punch. The scenario shown above is the PERFECT scenario for gobs of snow for Seattle. We have a split jet stream in the upper atmosphere, with one branch coming into our area from Canada and one coming off the Pacific. You can see a developing low pressure system in the far left corner of the picture. This comes onshore just north of Astoria, as evidenced down below.
The crucial key here is that it goes close enough to us to provide us with ample moisture, yet it goes south so it draws in a cold northerly wind. That's why the models are going crazy with snow amounts. If this does verify, we could see the biggest snowfall we have seen in at least 15 years, going back all the way to December 1996.
But it is a big if.
I'll keep you posted. :)