If you remember more than a week out before the last storm all the models were showing was a cold trough pushing down the West Coast with maybe some snow showers.  Then as we got closer it became apparent that the cold low would come down off the coast and draw in lots of moisture off of the ocean.

It has been like dejavu this week watching the cold trough that will dig down the West Coast the end of next week.  When you have these scenarios the track of the lows down the coast over land vs over the ocean makes a huge difference.  All week the models have been mostly saying the trough digs down more over land with only lighter snows next weekend.  The trend now is further offshore with more and more moisture being pulled in off the ocean.  These scenarios are great for cold powdery snowfall for the Sierra.

With the positive PNA this week and the negative NAO pattern the blocking in the North Atlantic has the whole pattern stuck.  We have had the trough in the East and the ridge over the West.  We will see a reversal going through next week and the high pressure in the North Atlantic will move East allowing the trough to move East and the ridge over the West.

Meanwhile over the North Pacific high pressure will build in over Alaska and extend way South down along 140w off the coast.  That will allow a cold trough to carve its way really far South down the West Coast.  The amount of snow is not certain right now as it is not clear the exact path and how much Pacific moisture we will get, but it will be a really cold weekend.  If you want to get out and hike and enjoy nice weather get out this weekend.  A lot of the snow is gone from lake level.

Here is an example of the temperature change between next Tuesday’s warmth and then on Saturday.

Looking at the long-range the ridge may stay off the coast allowing another storm to dive in at the end of next weekend into the following week.  After that the storm track may jog just to our North again around mid-month.  The CFS v2 model shows dry conditions over Central CA through the 3rd week of November before ridging builds in the Gulf of Alaska towards the end of the month and the storm track shifts further South.

Stay tuned….BA

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