Batten Down the Hatches! Rain, Wind, Snow Arriving Tuesday Afternoon

The storm that Northern California has been waiting for through a long, dry fall is almost here.

Rain, occasionally heavy, will arrive by late Tuesday afternoon and continue into Wednesday.  By Thanksgiving, which should be showery and cool, much of the North Bay will have received an inch of rain and in spots a bit more.

You can see the storm diving south from the North Pacific Tuesday at noon.

By late afternoon Tuesday, a deep low pressure center and cold front will bring rain to Northern California, spreading south through the night and into Wednesday.

By Friday, rain totals from the first storm will range upwards of an inch across the North Bay.  Here is the blended average of around 100 forecast models.

Cold weather will follow the storm, with the coldest days and nights of the season.  Some locations in the North Bay will likely drop into the upper 20s Thursday and Friday nights.  Daytime highs will struggle to reach the low 50s.

Then, most models have come into agreement that another low pressure center and frontal system will bring us rain beginning Saturday.   It will not be as cold, but this storm may be even wetter than the Tuesday-Wednesday storm system.

Here’s the predicted setup for late on Saturday night.

In fact, some computer models hint the Sat-Sun storm may tap into a small atmospheric river.  Not enough to cause flooding, but this may add to the rain totals across Central California.

Add all of this up, and most models show more than 3 inches of rain over the North Bay by next Monday.  Here’s the European model, showing areas well over 4 inches in parts of Sonoma County.

And the American GFS model outlook. Santa Rosa at 3.1 inches by late on Monday.

The WPC blended model shows very similar results, perhaps over 3 inches for the North Bay by late Monday.

Of course, this is days away, but the weekend outlook is definitely trending wetter.

And, if you’re headed to the Sierra, travel is not advised beginning Tuesday afternoon through Wednesday, and again on Saturday afternoon into Sunday.  Unfortunately that corresponds with some busy Thanksgiving travel periods.

Heavy snow, high winds, and cold temperatures will snarl traffic during those days, and snow will fall to low elevations…perhaps as low at 1500 feet, especially during the first storm on Tuesday and Wednesday.  Up to 5 feet or more of snow may fall at the pass level by early next week.  Snow may even accumulate on Bay Area peaks above 2000 feet on Wednesday.

So, a wet and wild week ahead.  But after our extremely dry fall and extended fire season, most Californians are looking forward to the first big rains and snows of the season.  Enjoy!