Joe Lundberg

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A Series of Waves Ready to Break the Tranquility on the West Coast

November 15, 2012; 10:31 AM ET

Thursday, 11:05 a.m.

Let's face it. The weather across the country right now is quiet... VERY quiet. About the only truly adverse weather is over the Southeast, where a very weak low off the Southeast coast is working in concert with an upper-level disturbance crossing the region to generate lots of clouds around the region:

Along with those clouds there is some rain, mainly over the Carolinas. As this disturbance moves off the Coast tonight, most of the rain will go with it, though it may be tougher to get rid of all these clouds around the region tonight and tomorrow. If anything, there may be some spotty showers along the east coast of Florida with the onshore flow persisting there tomorrow into the weekend.

Outside of that, though, there really isn't much going on right now. A lot of places are chilly, but hey! It's November! It gets cold at this time of the year, shockingly enough, even in Texas and Louisiana. There are no record highs to be found, and the one record low I saw this morning was 22 in Wheeling, W.Va., where the period of record just isn't very long, so I all but ignore that one. Even the cold front slipping across the Midwest into the Great Lakes is generating little more than some clouds and no rain.

It can't stay this quiet for long, and it won't. There are two areas of the country that will see some adverse weather going into the weekend and beyond. One we've been highlighting for days, now, and that's the East Coast. The other is the West Coast, where a series of waves are ready to break the tranquility of the weather there of recent days. More on that a bit later.

In looking more closely at the storm threat for the East, it is still on the table, even though the model trends over the past 24 hours have clearly been for this storm to be somewhat weaker and, more importantly, farther offshore. That sound you heard was the collective sigh of relief from the storm-weary residents of the mid-Atlantic and southern New England!

While these areas are clearly not out of the woods, a decisive shift in the storm track has taken place with the European model and its ensemble members. I believe that change is the models' thinking has come about thanks to an upstream feature that the models say will plow into the West Coast and keep right on going out across the Rockies and Plains early next week. Here's a look at the 144-hour GFS ensemble forecast for Tuesday evening:

If that second or trailing disturbance is real and to be believed, then it could well have the impact of pushing the lead system away from the Southeast coast and prevent it from developing all that strongly. That, at least, is the screaming message from the latest model runs. Oh, that other sound is the news writers groaning for lack of material to write about.

Lost in the noise of that image above is the fact that arctic air is bottled up over Alaska and western Canada into next week. Those higher-than-average heights from the northern Plains and Midwest into eastern Canada correspond to a fairly far position for the northern branch of the jet stream, and that will allow milder air to fan out from the Rockies back through the Plains and into the Midwest and Great Lakes this weekend into the beginning of next week.

That same image, though, clearly shows the strength of the upper-level low in the northeast Pacific, and it's one that will spit disturbance after disturbance at the West Coast this weekend into next week.

The first of these is actually two separate features, one in the Gulf of Alaska and another off the southern California coast:

As these two separate entities move toward the West Coast, it will get wet, especially later tomorrow and tomorrow night. The snow levels will be relatively high in the Sierra and the Cascades, but a front moving inland on Saturday should bring them down in the afternoon, especially in Washington and Oregon.

That's just the first salvo being shot at the region. The next one comes in some 24 hours or more later, depicted below by the 84-hour NAM forecast for Sunday evening:

Both the GFS and the European models suggest this will bring a lot of rain to western Oregon Sunday night, spreading into northern California with time. And they both imply another feature races right into the back side of this one to sort of 'blow it up' and reinvigorate the rain and mountain snow later Monday and Monday night into Tuesday. I could easily see 5 to 10 inches of rain between Sunday and Tuesday in portions of northern California and western Oregon from this, with several feet of snow piling up in the mountains!

Sadly, the series of disturbances or storms or fronts coming at the region doesn't end there. We'll probably get a break of 24 hours or more, but still more are waiting in the wings for Wednesday or Wednesday night into Thanksgiving Day, as well as late next week into next weekend. This won't get the headlines of recent storms in the East, and understandably so. Nevertheless, it will mark a period of very active weather impacting most of the West Coast, specifically from around the Bay Area on north.

The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com

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Joe Lundberg
Joe Lundberg, a veteran AccuWeather.com forecaster and meteorologist, covers both short and long-term U.S. weather on this blog.