SLO County weather: Sunny afternoons and foggy mornings this week

Last week’s upper-level low-pressure system produced 0.42 of an inch of rain at the San Luis Obispo County Airport. The average amount of rain at the airport for May is 0.47 of an inch. The rest of this month looks dry. By the way, Santa Barbara saw nearly one inch of rain!

A weak front will move the Central Coast early Sunday morning with increasing mid to high-level clouds and low marine clouds along the coastline. Many beaches will remain overcast for most of the day. Temperatures will reach the high-60s in the inland valleys (Paso Robles), the mid-60s in the coastal valleys (San Luis Obispo), and the high-50s along the beaches on Sunday.

A typical May “May Gray” weather pattern with night and morning low marine clouds and fog with pockets of mist clearing by the afternoon as fresh to strong (19 to 31 mph) northwesterly winds develop. Temperatures will remain mild, on average about 5 to 10 degrees below normal from Sunday into Monday.

A dry cold front will move through the Central Coast on Tuesday. In the front’s wake, strong to gale-force (25 to 38 mph) northwesterly winds and clearing skies will develop on Tuesday into Friday. These winds will create more sunshine during late morning and afternoon; consequently, temperatures will warm to the mid-70s in the inland valleys and the high-60s in the coastal valleys, while the beaches will remain cold.

Surf report

A 3- to 5-foot northwesterly (290-degree, deep-water) swell (with a 7- to 13-second period) is expected along our coastline on Sunday into Monday.

Combined with this northwesterly sea and swell will be a 1- to 3-foot (220-degree, deep-water) southern hemisphere swell (with a 15- to 17-second period) on Saturday into Monday.

Gale-force northwesterly winds along the coastline will generate a 6- to 8-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 11-second period) on Tuesday through Friday.

Seawater temperatures will range between 52 and 54 degrees through Monday, decreasing to 50 to 52 degrees on Tuesday into Friday.This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

John Lindsey is a retired PG&E marine meteorologist. Email him at JohnLindseyLosOsos@gmail.com or follow him on Twitter @PGE_John.