On Jan. 7, the North American Ensemble Forecast System, a joint effort of the National Oceanographic and Atmospheric Administration, the Meteorological Service of Canada and the National Meteorological Service of Mexico forecast wild weather for the Central Coast the following week.
Sure enough, about a week later the midlatitude westerly winds at the surface and in the upper levels of the atmosphere dramatically increased, while the eastern Pacific high shifted southward.
In other words, this condition pointed the storm track straight at the Central Coast. As if on cue, a series of strong and vigorous weather systems marched across the Eastern Pacific toward our area.
The first system in the series arrived along our coastline on Monday. A powerful storm developed off the coast of Northern California and the associated cold front rapidly intensified as it moved down the Central California coast.
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It produced periods of heavy rain and gale force southerly winds with gusts up to 56 mph at Diablo Canyon Power Plant and even stronger winds as it moved toward Vandenberg Air Force Base.
The strongest winds occurred at Condor Lookout in the Los Padres National Forest on Hi Mountain (3,198 feet), reaching 88 mph. Those are hurricane force winds!
The swell at the Diablo Canyon wave-rider buoy reached 19 feet with a 20- second period while the offshore marine buoys reached over 25 feet.
A second system rolled into San Luis Obispo County late Tuesday morning and contained a cooler and fairly unstable air mass which produced a few thunderstorms and much-needed rain.
I had originally forecast that Wednesday’s storm would be the strongest of the bunch. I woke up early that morning to a relatively calm day thinking I had blown the forecast, and wondered how I was going to explain it.
As I was walking up the steps to the office, an intense band of thunderstorms announced the arrival of a vigorous cold front. Sustained southeasterly winds rapidly increased to 54 mph with gusts reaching 66 mph at Diablo Canyon.
These wind speeds were in the top 10 percent of all high wind events since weather records have been kept at the power plant (1976). After the front passed, multiple thunderstorms produced hail, lightning and brief heavy rain. Another cold front passed our area on Thursday with additional rain.
The six-day rainfall total at Diablo Canyon reached a near-record high of 5.75 inches.
All this rain has put a dent in the county’s hydrological deficit. Nacimiento Lake went from 16 percent of capacity on Monday to more than 31 percent by Friday. The lake’s depth increased by more than 20 feet during this period. Lopez Lake has increased to 52 percent of capacity, and Salinas Reservoir (also known as Santa Margarita Lake) has reached 61 percent.
This week’s forecast
Except for areas of dense ground fog this morning, high pressure over Central California will produce clear to partly cloudy conditions through this afternoon.
Temperatures today will be cool, mostly in the upper 50s and maybe a few low 60s along the coastline. Minimums tonight will be mostly in the mid- to high 40s.
Clouds will increase later today, as a cold front moves southward down the California coast. This cold front will produce rain showers overnight tonight and rain on Monday with moderate to fresh (13-24 mph) southerly winds.
Rain will turn to showers on Tuesday morning and afternoon, ending by Tuesday night.
Total rainfall amounts on Monday through Tuesday should range between 1 and 2 inches across most low elevation locations and 2 and 3 inches along our coastal-facing mountains because of orographic enhancement.
Fair weather will return Wednesday and Thursday. Increasing southerly winds and rain are forecast late Friday into Saturday.
Surf and sea report
This morning’s 8- to 10- foot west-northwesterly (285-degree deep-water) swell (with a 12- to 14-second period) will decrease to 6 to 8 feet by this afternoon and will remain at this height and period through Monday morning.
Combined with Monday’s swell will be 3- to 5- foot southerly (180-degree shallow-water) seas.
An 11- to 13-foot west-northwesterly (285-degree deep-water) swell (with a 15- to 17-second period) will arrive along the Central Coast on Monday afternoon and will continue at this height through Tuesday morning.
This swell will decrease to 7 to 9 feet by Tuesday night, further lowering to 6 to 8 feet (with a 10- to 12- second period) on Wednesday.
This swell will continue to decrease to 4 to 6 feet on Thursday.
A long-period west-northwesterly (285-degree deep-water) swell (with an 18- to 20-second period) will arrive along our coastline late Thursday night, increasing to 10 to 12 feet (with a 16- to 18-second period) on Friday.
Help with power bills
If you or someone you know is having trouble paying your Pacific Gas and Electric Co. bill, the company can help.
Please call 1-800-743-5000 to discuss program options and payment arrangements that work for you. Learn more about PG&E’s financial assistance programs at www.pge.com.
John Lindsey is a media relations representative for Pacific Gas and Electric Company. He is also a local weather expert and has lived along the Central Coast for more than 22 years.