BRUSHED BY COLD STORMS FOR NOW – MAJOR PATTERN CHANGE STILL SHOWING UP

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SHORT TERM FORECAST

On Saturday a cold, quick moving storm will brush the North Bay, sending most of its energy east into the Sierra where more than a foot of snow is expected.

Storms from the north are generally moisture starved because they reach California over land. But they are also cold.

You can see the storm headed in on satellite. It will dive south into California over next 24 hours.

NORTH BAY ON THE FRINGE

As the system drops in from the north, showers should arrive across the region Saturday morning. The North Bay will be on the western fringe of the storm and also in the rain shadow of the mountains in Northwest California.

You can see we’ll be lucky to pickup a tenth or two of rain. But it will feel colder and blustery as the storm brings in a blast of chilly air.

WEDNESDAY STORM

The forecast models have recently been showing another similar storm arriving Wednesday as disturbances “pinwheel” around the high pressure dome to our west, and drop into the Great Basin.

This one could have a path that takes it a bit more over the ocean, where it could pick up some additional moisture.

Even if this storm manages to pick up additional moisture, much like the Saturday storm this one will be dropping in from the north, so most of the moisture will fall in the mountains of NorCal and the Sierra.

We’ll likely just pick up a tenth or two of rain in the North Bay once again.

LONGER RANGE – HINTS OF A PATTERN CHANGE

Starting this weekend some of the coldest air of the winter will settle in over the West. Most of California will feel noticably colder, especially Sunday and Monday. After that, temperatures will begin to moderate a bit.

We’re still expecting a pretty major change in the pattern beginning around mid-month, when storms from the north may be replaced by storms approaching California from the west.

As you can see, the blocking high pressure dome to our west is forecast to shift north toward Alaska, and the cold low pressure trough over the West may move east. This may allow the storm track to undercut the ridge into California which you can see at the end of the loop.

All of this matches up well with the jet stream forecast which ensemble models show extending straight east across the Pacific starting around mid-January. That’s a pattern that could direct warmer, wetter storms into California.

And the models are now in decent agreement on a wetter pattern for California beginning around the 13th, and continuing into the third week of January at least.

If it verifies in the days ahead this is a forecast that may help reduce California’s rainfall deficit so far this season. It is also more of what you would expect in a “typical” strong El Nino season.

We’ll keep an eye on trends and have further updates in the days ahead.