Weak Storms For Now. Atmospheric River Midweek?

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A long-anticipated pattern change in our weather is now underway. This change has the potential to bring large amounts of rain and snow to California beginning on Tuesday. But, as always during this mostly dry La Nina year the question is, will it deliver?

We currently have an active North Pacific Ocean, showing the first weak but cold storm following the jet stream south to California. (Image 1) Its trajectory is too close to the coast to pick up much ocean moisture. This is our Friday storm.

A second storm will arrive on Sunday. This one will follow a path further off the coast and will be slightly wetter. It is expected to bring about a quarter of an inch of rain to Sonoma County. (Images 2 and 3)

These storms are being driven south by a strong jet stream just off the California coast. (Image 4)

By Tuesday and Wednesday of next week the jet stream position and storm track is expected to change to one more favorable to support wetter storms, with a trajectory over the ocean. (Image 5)

Here is the forecast storm for Tuesday and Wednesday. (Image 6)

The storm may draw in a significant amount of moisture in a moderate Atmospheric River. We’ll have to wait and see. (Image 7)

If that happens, the moisture tap would likely be colder than our normal pineapple express events, bringing rain but still chilly temperatures. (Image 8)

What it could mean is big rains for the North Bay and much of Northern and Central California by Thursday. Here’s an average of various models. This is total rain which includes the meager amounts we receive before Tuesday. (Image 9)

We know what many of you are saying. We’ve heard this before. Yes, we agree. We will have to wait to see if all of this takes place. But there is decent model agreement for now, and models continue to trend wetter.

After that? Perhaps another significant storm next weekend. Timing is not certain, but some models are forecasting another inch or two by February 1st. This is total rain from now until then according to the European model. Looks good, but once again we’ll just have to cross our fingers for now. (Image 10)