Big, bright supermoon rises over SLO County

The brightest moon in almost 69 years was lighting up the evening sky in San Luis Obispo County on Monday. The so-called supermoon — the closest full moon of the year — can appear 14 percent bigger and 30 percent brighter in the night sky.

The last time the moon was so close — actually, 29 miles closer — was in January 1948. In 2034, the moon will come even closer, within 221,485 miles. That, too, will be a supermoon.

Not only is the moon appearing to be brighter and larger, but we will also see some of the biggest tides of the year (king tides).

Tides are enhanced when Earth is at perihelion (the closest point in its orbit to the sun) and the moon at perigee (the closest point in its orbit to the Earth), according to PG&E meteorologist John Lindsey. The gravitational forces exerted by the moon and sun are at their greatest at this time. These “tidal forces” are not the total gravitational forces exerted by the sun and moon on Earth, but the difference between these gravitational forces over the surface of the planet.

This tugging produces a tidal “bulge,” or area of higher sea level on the ocean’s surface.

On Nov. 15, the high tide will reach 6.7 feet at 9:35 a.m. Later in the day, the low tide will drop to -1.3 feet at Port San Luis.

This story was originally published November 14, 2016 at 7:22 PM with the headline "Big, bright supermoon rises over SLO County."