It’s difficult to believe with the current Gulf of Alaska storm bearing down on the Central Coast, but today is the first day of spring.
Spring is a transition season in terms of weather conditions: not quite summer and not quite winter. You may have stormy weather one day followed by record-breaking heat nearly the next.
However, spring along the Central Coast usually means constant northwesterly winds. It’s interesting reading old weather reports from the early 1900s in San Luis Obispo; locals often called these winds the “Los Osos winds” as they blew in from the Los Osos Valley off the Pacific Ocean.
These onshore winds create a great amount of upwelling along our coast, resulting in the coldest seawater temperatures of the year.
It’s not uncommon for seawater temperatures along the immediate coastline to drop to 47 degrees — that’s just flat cold. You just never get warm diving in 40-degree water, no matter how thick your wetsuit.
Because the calendar year is not exactly 365 days, the first day of spring in the Northern Hemisphere ranges from March 20 to 21.
Earth is on a 23½-degree tilt as it rotates around the sun. This is the reason we have seasons. As Earth orbits around the sun during this time of the year, the Northern Hemisphere becomes more tilted toward the sun, while the Southern Hemisphere tilts away.
When the sun is directly over the equator today, at 4:22 p.m., it’s called the vernal equinox. Equinox comes from the Latin phrase for “equal nights.”
However, sunrise and sunset are about 12 hours apart everywhere on Earth on this date, but the sunrise and sunset times listed on the PG&E Diablo Canyon weather forecast are not exactly 12 hours apart, as one might suspect.
That’s because Earth’s atmosphere refracts or “bends” light coming from the sun, so we see the sun a couple of minutes before it actually rises over the horizon and a couple of minutes after the sun sets.
Also, sunrise is classified as the moment the upper edge of the sun’s disk appears on the horizon, and sunset is when the upper edge disappears below the horizon adding to the slightly longer days.
As a kid growing up in Santa Rosa, one of the more interesting urban legends that I often heard was the one about easily balancing eggs on their ends during the equinox because of the equal length of the day and night.
With enough patience and practice, you can balance eggs on their ends at any time of the year just as easily as during the first day of spring.
This week’s forecast
A strong 987-millibar low-pressure system with dynamic upper-level support and its associated cold front will move into California this morning.
This system will produce moderate gale to fresh gale (32- to 46-mph) southeasterly winds with gusts to 50 mph along the coast.
This morning’s moderate to heavy rain will continue through this afternoon, turning to rain showers tonight.
Rain showers will linger through Monday. Current snow levels are near 3,500 to 4,000 feet north to south.
Significant precipitation totals are expected with this system, with expected rain totals ranging from 1.5 to 3 inches in the coastal valleys and along our beaches, and from 3 to 5 inches along higher elevations of the coastal mountains.
Tuesday is likely to be the calmest day of the next seven, with partly cloudy skies and gentle winds.
However, unsettled weather will redevelop Wednesday as yet another low-pressure system moves down the California coastline and produces increasing southerly winds and rain through Thursday.
Surf and sea report
A 987-millibar storm off our coastline will generate moderate gale to fresh gale (32- to 46-mph) southeasterly winds with gusts to 50 mph this morning.
These winds will generate 11- to 13-foot southerly (200-degree shallow-water) seas (with a 4- to 8-second period) today.
A 936-millibar storm with hurricane force winds developed off the Kamchatka Peninsula a few days ago. This storm will produce a 7- to 9-foot northwesterly (300-degree deep-water) swell (with a 20- to 22-second period) along our coastline Monday, increasing to 8 to 10 feet (with an 18- to 20-second period) Tuesday.
Another round of increasing southerly winds will produce 6- to 8-foot southerly (190-degree shallow-water) seas (with a 4- to 6-second period) Wednesday and Thursday, followed by a 14- to 16-foot northwesterly (290-degree deep-water) swell (with a 14- to 16-second period) Friday.
Arriving from the southern hemisphere:
A 1- to 2-foot southern hemisphere (230-degree deep-water) swell (with a 20- to 22-second period) will arrive along our coastline Wednesday, increasing to 2 to 4 feet (with a 15- to 17-second period) by Thursday.
Seawater temperatures will range between 50 and 52 degrees through Monday.
Learn more from PG&E
PG&E has a new online site to provide its customers with news, information and commentary about the wide array of issues that connect PG&E with the communities it serves throughout Northern and Central California.
“Currents – News and Perspectives from Pacific Gas and Electric Company,” can be found at www.pgecurrents.com
Preparing for Power Outages
Have battery-operated flashlights and radios with fresh batteries ready.
If you have a telephone system that requires electricity to work (such as a cordless phone or answering machine), plan for alternate communication. Have a standard telephone handset or cellular telephone ready as a back up.
Freeze plastic containers filled with water to make blocks of ice that can be placed in your refrigerator or freezer during an outage to prevent foods from spoiling.
Outage Safety Tips
Treat all downed power lines as if they are ‘live’ or energized. Keep yourself and others away from them. Call 911, then notify PG&E at 1-800-743-5002.
Use battery-operated flashlights, not candles.
Customers with a generator should make sure they are properly installed by a licensed electrician. Improperly installed generators pose a significant danger to PG&E crews.
Unplug or turn off all electric appliances to avoid overloading circuits and fire hazards when power is restored. Simply leave a single lamp on to alert you when power returns. Turn your appliances back on one at a time when conditions return to normal.
John Lindsey is a media relations representative for PG&E. He is also a local weather expert and has lived along the Central Coast for nearly 25 years. To subscribe to his daily weather forecast or ask him a question, email firstname.lastname@example.org.