SLO County weather forecast: Expect foggy coastline, warm weather this week

A classic Central Coast weather pattern with fog at the coast and clear and warm skies in the coastal and inland valleys will continue through early this week, then gale-force northwesterly winds and cooler temperatures will develop in the later half of the week.

Fresh to strong (19 to 31 mph) afternoon northwesterly winds will continue into Tuesday, increasing to strong to gale-force (25 to 38 mph) levels during the afternoon on Wednesday through Saturday along the shoreline.

This condition will allow the marine layer to develop along the coastline and surge into the coastal valleys during the night and morning with areas of fog and pockets of drizzle into next week. Consequently, many of the northwesterly facing beaches (Morro Bay and Los Osos) will remain mostly overcast; however, the southerly facing beaches of Cayucos, Avila Beach and Shell Beach will clear during the afternoon.

Away from the ocean, high pressure will produce warm to hot temperatures. In fact, triple-digit heat is forecast in the inland valleys (Paso Robles) and mid-80s in the coastal valleys (San Luis Obispo) on Sunday into Tuesday.

High pressure will begin to weaken and shift eastward on Wednesday, as a trough of low-pressure approaches from the northwest, resulting in cooler temperatures and stronger northwesterly (onshore) winds. The cooling trend will continue mid to late week with daytime highs forecast to fall back to below normal across the inland and coastal valleys. The beaches will continue to see night and morning marine clouds with areas of fog and mist and cool temperatures.

Warmer weather could gradually return the following week as high pressure rebuilds over Central California.

Surf report

Sunday’s 4- to 6-foot northwesterly (300-degree, deep-water) sea and swell (with a 5- to 8-second period) will remain at this level into Monday.

A 5- to 7-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 8-second period) will develop on Tuesday and will remain at this level through Thursday, increasing to 6- to 8-feet with the same period on Friday into Saturday.

Sunday’s 1- to 2-foot Southern Hemisphere (220-degree, deep-water) swell (with a 13- to 15-second period) will gradually decrease on Monday.

Seawater temperatures will range between 54 to 58 degrees through Friday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

PG&E safety tip

Warm weather is expected this weekend. Follow these tips to stay cool and save energy: http://pge.com/tips.

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.