SLO County weather forecast for the week of Oct. 31: Overcast to warm, clear skies

This week, a tale of two weather patterns will develop; it will start misty, calm, and overcast and finish with blustery, warmer, and mostly clear skies.

A low-pressure system will move into Northern California on Sunday with rain showers. The associated cold front will significantly weaken when it reaches the Central Coast; however, it will deepen the marine layer.

This condition will produce increasing clouds with areas of fog, mist, and even pockets of drizzle during the night and morning on Sunday and continuing through Monday morning.

In other words, it will be a dreary and spooky night on Halloween. High temperatures will only reach the 60s on Sunday and Monday.

A stronger cold front will approach the Central Coast Monday night into Tuesday morning with increasing clouds and drizzle/light rain. The European Center for Medium-Range Weather Forecasts and NOAA’s Global Forecast System model indicates about a tenth of an inch of rain north of Morro Bay. At the same time, areas south will only see a few hundredths of an inch.

Thunderstorms are not expected with this weather system and will be relatively mild with snow levels above 8,000 feet.

Cool and cloudy weather is expected on Tuesday into Wednesday as another trough of low pressure pushes into Northern California. Most of the shower activity should remain north of Big Sur. However, an associated cold front may hold together enough to produce pockets of drizzle/light rain showers later Wednesday/early Thursday.

In this system’s wake, increasing high pressure and strong to gale-force (25 to 38 mph) northwesterly winds will develop on Thursday through Saturday. These winds will produce mostly clear skies and gradually warmer temperatures.

Surf report

Sunday’s 3- to 5-foot northwesterly (290-degree, deep-water) swell (with an 8- to 12-second period) will remain at this level through Sunday night.

A 3- to 5-foot west-northwesterly (280-degree, deep-water) swell (with an 18- to 20-second period) is forecast to arrive along our coastline on Monday, increasing to 6- to 8-feet (with a 15- to 17-second period) on Tuesday. This swell will decrease to 5- to 7-feet (with an 11- to 14-second period) on Wednesday.

Increasing northwesterly winds will generate a 5- to 7-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 14-second period) along our coastline Thursday through Saturday.

Seawater temperatures will range between 56 and 58 degrees through Saturday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

PG&E safety tip

Areas of dense fog with mist and drizzle will reduce driver visibility and produce slippery road conditions. Please slow down and give yourself extra time to reach your destination.

John Lindsey’s is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at pgeweather@pge.com or follow him on Twitter @PGE_John.