MODERATE STORM SATURDAY – MAYBE MORE NEXT WEEK

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SHORT TERM – THROUGH SUNDAY

An impressive looking Pacific storm system is bearing down on California Friday, and once again the North Bay will be on the southern edge of the heaviest rain.

You can see the storm rounding the top of the high pressure dome to our west, and coming in from the north.

This is because blocking high pressure to our west is still sending the steering winds of the jet stream north.

By Saturday afternoon a plume of moisture will stretch toward California. How far south it reaches before weakening will determine how much rain we get here in the North Bay.

In the last day or two the GFS model has gone from the driest to the wettest. The total model average is more reliable and shows us getting from about an inch to over 2 inches in the wetter spots of the North Bay by Monday.

Most models show the rain arriving in the North Bay around 5AM Saturday and progressing from north to south through the day. The storm will clear out by early Sunday, with sun reappearing for a nice day.

NEXT WEEK

The models disagree about a possible storm reaching us next Wednesday. The European and Canadian models show it pushing this far south, the American GFS doesn’t.

In any case, most models show this to be a fairly minor storm, with light rain totals by Thursday.

FURTHER AHEAD – SIZABLE STORM NEXT WEEKEND?

The extended forecast has a fairly juicy storm arriving on Saturday the 21st. It is way too early to forecast rainfall amounts but we’ll be watching this one. It may be the first storm to ride the “extended” jet stream across the Pacific into California after the blocking high pressure dome (that’s been sending storms north) weakens.

You can see the jet stream pointed at California in the 2nd image below. This is the European deterministic outlook.

Some of the models like the Euro hint that this may be a 2 day storm, from Saturday through Sunday, with another storm right on its heals around Monday or Tuesday. The American GFS has yet to jump on board in forecasting this wet period. It keeps us pretty dry, while the European brings in the rain with above normal rain beginning around the 19th or 20th.

Here’s the GFS ensemble first, followed by the (much) wetter European ensemble.

For its part the Canadian ensemble model is as wet, or wetter than the European beginning around the 20th.

As has been the case for much of this winter, the models are way out of sync. But, based on their track records this winter I’d lean toward the wetter European and Canadian solutions.

We’ll watch this closely and let you know how things pan out as the event draws closer. Stay tuned!