Good news? Rain! Bad news? So, about those Thanksgiving holiday plans ...

Temperatures will drop; thunderstorms could pummel region

Talk about lousy timing. After nearly 200 days without any significant rainfall, the San Francisco Bay Area is about to get soaked, just in time to muck up our Thanksgiving plans. Temperatures are expected to drop while showers, and perhaps even thunderstorms, will pummel the region this week, tamping down the risk of wildfires after gusty offshore winds ramped up that risk again Monday.

“A strong cold front will move north to south on Tuesday, ushering in colder temperatures and unsettled weather for Thanksgiving week,” the National Weather Service said.

Rainfall from today through Turkey Day will range from .75 to 1.5 inches around the Bay Area to as much as 2 inches in the coastal mountains, forecasters said, while the Sierra Nevada will get heavy snow and places like Mount Diablo could see a light dusting of powder before the week is over.

This storm system appears to be front-loaded, with the heavier rains, possible hail and thunderstorms hitting the region tonight and into Wednesday. Chillier weather is expected to accompany that rain, with highs in the upper 40s and low 50s and lows possibly down to the upper 20s.

“This system is still up over the Pacific Northwest and is continuing to move south,” forecaster David King with the National Weather Service in Monterey said Monday afternoon. “But by Tuesday around 4 p.m., the North Bay could start seeing the rain. And by Tuesday evening, with the start of the main event, we’ll see rain move south into Wednesday morning.”

“We’re expecting the rain to be heavy at times and we’ll possibly see thunderstorms as the system moves north to south before it starts to stall,” King added.

While there’s a chance for some rain on Thanksgiving morning, Bay Area skies should be mostly clear by Friday, King said.

“There may still be some intermittent light rain on Thursday, and we cant rule out maybe an inch of snow along the Diablo Range,” he said.

The rain will come with

plenty of wind out of the southwest as well, he said, adding that the weather service has issued a wind advisory with speeds up to 30 mph and gusts as high as 50 and even 60 mph, though those will mainly be at higher elevations.

The NWS has also issued a high surf advisory from 7 p.m. today until 3 p.m. on Wednesday, with northwest swells as high as 20 feet feet and breakers of up to 27 feet. In its announcement, the weather service said “large breaking waves along the coast will lead to increased wave run-up on beaches with waves topping and washing over large rocks

and jetties,” and urged people to “use extra caution near the surf zone as these large waves will be capable of sweeping people into the frigid and turbulent ocean water.”

“Cold water shock may cause cardiac arrest,” said the advisory, “and it also can cause an involuntary gasp reflex causing drowning, even for a good swimmer. The surf zone will be

dangerous due to strong currents and powerful breaking waves.”

Forecasters advised

people to be careful on or near the coast, adding that such an advisory “means that high surf will affect

beaches in the advisory area, producing rip currents, localized beach erosion and sneaker waves.”