SLO County weather forecast for the week of Oct. 17: Light rain, then mostly sunny

The last few days have been warm and dry as high pressure remained in control of the weather pattern and produced Santa Lucia (offshore) winds; however, a change may be on the horizon.

Gentle to moderate (8 to 18 mph) southerly winds will develop on Sunday as high pressure over Central California weakens and a cold front moves southward along the California coastline. This low-pressure system will bring rain as far south as Monterey Bay. Mountain snow above 5,000 and 6,000 feet as far south as Yosemite.

Along the Central Coast, low marine clouds will develop in the coastal regions by Sunday afternoon. This front will wash out over the Central Coast Sunday night into early Monday morning, producing increasing mid to high-level clouds, fog, and pockets of heavy drizzle/light rain showers.

Sunday’s high temperature will range between the high-60s to the low 70s throughout the Central Coast.

In the wake of Sunday night’s cold front, moderate to fresh (13 to 24 mph) Santa Lucia winds, and mostly clear skies will develop Monday morning. Strong to gale-force (25 to 38 mph) northwesterly winds will follow on Monday afternoon, decreasing Monday night.

Another round of moderate to fresh (13 to 24 mph) Santa Lucia winds on Tuesday morning will keep the skies clear; however, a pattern of moderate to fresh (13 to 24 mph) northwesterly (onshore) winds developing during the afternoon, decreasing during the night and morning is forecast on Tuesday afternoon through Friday. Over this period, areas of fog and mist are expected during the night and morning, becoming mostly clear and sunny during the afternoon with mild temperatures.

It is a long way out, but the WAVEWATCH III wave model, a one-way coupled model with the Global Ensemble Forecast System (GEFS), is advertising gale-force southerly winds, high west-northwesterly sea, and swell, and rain on Oct. 24, 25, and 26.

Remember, these are extended range models and will undoubtedly change as we get closer to next weekend, but many of the models are settling on this solution.

Surf report

Sunday’s 3- to 5-foot northwesterly (290-degree, deep-water) swell (with an 8- to 14- second period) will remain at this level through early Monday morning.

Gale-force northwesterly winds off the Central California coastline will generate a 5- to- 7-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 13-second period) on Monday late morning through Monday night, decreasing to 4- to 6-feet (with a 7- to 13-second period) on Tuesday.

A 2- to 4-foot northwesterly (290-degree, deep-water) swell (with an 8- to 12-second period) is forecast on Wednesday morning, rapidly building to 5- to 7-feet (with an 8- to 14-second period) on Wednesday afternoon and will remain at this level through Saturday. High west-northwesterly sea and swell could develop along our coastline on Oct. 24, 25, and 26.

Seawater temperatures will range between 52 and 54 degrees through Monday, increasing to 55 to 58 degrees on Tuesday into Friday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

PG&E safety tip

Now is a great time to prepare for stormy weather in advance with PG&E safety tips, please visit www.pge.com.

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.