Little Storms

Monday, November 26, 2012
1:37 P.M.

I was looking at the models this afternoon, and I noticed that there are a lot of little storms slated to hit our area later this week into next week. None of these storms look particularly strong. In some ways, they look kind of cute… in a nerdy meteorological way. If our rainstorm/windstorm last Monday was a bulldog, these storms would be adorable little pugs. Of course, I’d take a big bad storm any day over a cute one, but if I look at these storms from this perspective, maybe it’ll tide me over until we get another fat cyclone headed our way.

Before I get any further, I’ll show you the current 500mb chart over our area. Atmospheric scientists are obsessed with the 500mb level charts and use them all the time to determine upper-level flow patterns and the jet stream.

Valid 04:00 am PST Mon, 26 Nov 2012 – UW 12z WRF-GFS, 36 km 500mb absolute vorticity, heights
As you can see, there is currently a pretty sizable ridge over the West Coast from California to Alaska and a big ol’ trough around 150 west. This ridge has been giving us the sunny weather with rather cool nights we have seen of late. I’m trying to go to 2013 without wearing long pants (apart from special occasions like weddings and stuff), but I was pretty darn chilly this morning in my gym shorts.
Over the next few days, this trough will drift on in to our region and we will start to feel its effects.
Valid 10:00 am PST Thu, 29 Nov 2012 – 78hr Fcst – UW 12z WRF-GFS, 36 km 500mb absolute vorticity, heights
The ridge has fallen off the wayside and we have a broad and modest (with respect to wind velocity) jet stream over the Pacific Northwest. The main upper level low around 140 west and 50 north will act as a chauffeur, escorting a variety of classy, well-mannered storms into our area.
The first of these storms will arrive Thursday. It could bring 2-3 inches of rain to the Olympics, which just might be enough rain to push the Skokomish River over flood stage. But this front will sag south over northern California and deliver copious amounts of moisture to the area via an atmospheric river. Take a look at the picture below!
 Valid 04:00 am PST Sat, 01 Dec 2012 – 120hr Fcst – UW 12z WRF-GFS, 12 km 48 hour precip, wind vectors
The WRF is forecasting 10-20 inches of rain in some regions, and it has been pretty consistent with this feature. Northern California should take action and prepare for river flooding.
After that, the details get really mushy as far as storms go. The good news is that I am fairly certain that the mountains will pick up some decent snow amounts with this pattern. The snow level looks like it will be all the way up to 8,000 feet early in the week and gradually settle down to around 5,000 feet by Friday. After Friday though, models show the snow level dropping below 3,000 feet, which means Snoqualmie Pass will get some snow and will probably open soon. 
Valid 04:00 pm PST Mon, 03 Dec 2012 – 180hr Fcst – UW 12z WRF-GFS, 12 km 24-hour snowfall
I’m dying to get back on the slopes!
Enjoy your Monday!
Charlie
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