This fall has been mostly warm and sunny so far, but winter weather is in the forecast starting Thursday night, Nov. 12.
The National Weather Service predicts light to moderate rain, increasing through Saturday afternoon. The total rainfall expected is up to 0.8 inches for the coastal portion of Monterey County, up to 0.5 inches inland and up to 1.25 inches in the Santa Lucia Mountains.
The arriving storm, coming from the Gulf of Alaska, is likely to bring wind gusts of 25mph to 35mph.
It's much less about the rain than the ocean conditions that National Weather Service officials want the public to be aware of, with a combination of factors leading to hazardous conditions: a high tide, thermal expansion due to relatively warm ocean water and a big swell. Waves of up to 35 feet are predicted, with sets as high as 50 feet as breakpoints. Rip currents and sneaker waves are in the forecast starting on Friday, Nov. 13.
"The wording can't be strong enough: to stay away from the water, no getting on jetties, not getting on rocks," says Joe Merchant, a meteorologist at the National Weather Service's Bay Area station in Monterey. "We are really trying to get the word out that any wrong move and you could be dead.
"We can't stress enough how dangerous and deadly it's going to be close to the water."
Merchant describes the confluence of conditions by comparing it to a bathtub. Thermal expansion means the water simply takes up more volume than usual, adding an inch or two to an already-high ride. (The next high tide, at 11:34am on Friday, is predicted to be 5.17 feet in Monterey.)
"Think about what happens when you push down in the surface of a tub," Merchant says. "You see the water rise on the edges." The equivalent in the upcoming weather is the low-pressure system (nature's version of your fist on the top of the bathtub water).
Coastal flooding is a possibility due to the combination of big waves, thermal expansion and high tides, but the rain is expected to be relatively modest and is unlikely to result in flooding.
Wave watchers should stay on high points overlooking the ocean, Merchant cautions, rather than go to beaches. He is hopeful that rainy conditions may mean fewer people are at risk, keeping ocean-watchers from getting too close to the water.
Stormy conditions may continue well into next week. "We are expecting another system to move through the region Sunday into Monday and a third system to arrive in the middle of the upcoming week," according to a National Weather Service forecast published on Thursday, Nov. 12. "These systems are not forecast to stall over any one given area, thus reducing the potential for widespread flooding concerns.
"It is a bit too far out in time to talk about thunderstorm potential and rainfall amounts, yet current forecast do not seem much greater than the Friday system."