Cooler weather on the way to SLO County this week. Is a chance of rain on the horizon?

A trough of low pressure over the Central Coast will produce a deep marine layer and below-seasonal temperatures this weekend.

This will be followed by a ridge of high pressure creating gale-force northwesterly winds along the shoreline, clearing skies, and warmer temperatures, especially away from the coastal regions during this upcoming workweek.

A trough along the California coastline this weekend will produce fresh to strong (19 to 31 mph) northwesterly winds during the afternoon, decreasing during the night and morning, which will allow a deep marine layer with pockets of fog and mist to develop during the overnight.

The marine layer will clear from the inland valleys (Paso Robles) in the morning, from the coastal valleys (San Luis Obispo) by the late morning, and from the beach communities by the afternoon.

Temperatures over this period will reach the low 80s in the inland valleys and low 70s in the coastal valleys. The beach communities will see high temperatures in the mid-60s.

This trough of low pressure will move northeastward while high pressure will build behind it, resulting in strong to gale-force (25 to 38 mph with gusts to 45 mph) afternoon northwesterly winds along the coastline and clearing skies throughout San Luis Obispo and Santa Barbara counties on Monday through Tuesday.

Over this period, high temperatures will reach the high 80s in the inland valleys (Paso Robles), high 70s in the coastal valleys (San Luis Obispo), and 60s along the beaches, except for Cayucos, Avila Beach and Shell Beach, which will reach the mid-70s.

A 978-millibar storm will develop in the Gulf of Alaska, with a weak trough of low pressure developing west of Central California on Wednesday into Thursday. This condition will give gentle to moderate (8 to 18 mph) northwesterly winds on Wednesday and moderate to fresh (13 to 24 mph) northwesterly winds on Thursday.

Overall, a deep marine layer should produce areas of mist and drizzle during the overnight and morning in the coastal regions. Away from the ocean, inland temperatures will warm to the mid- to high 90s, with the Central Valley reaching triple-digit temperatures. The coastal valleys will warm up to the mid-80s with high 50s to low 60s in the beach communities.

Another round of strong to gale-force (25 to 38 mph) northwesterly winds and clearing skies is forecast on Friday into next Sunday, with slightly cooler temperatures throughout the Central Coast.

The long-range models are advertising a late-season upper-level low-pressure system will move over Northern and Central California early next week (June 10, 11 and 12) potentially bringing thunderstorms, rain and snow in the Sierra Nevada mountains and even a chance of rain showers along the Central Coast. Stay prepared for these conditions.

Surf report

Gale-force northwesterly winds off the Northern and Central California coastlines will generate a 7- to 9-foot northwesterly sea and swell (with a 5- to 8-second period) on Sunday through Tuesday.

The storm in the Gulf of Alaska will produce 5- to 7-foot northwesterly swell (with an 8- to 15-second period) on Wednesday into Thursday, followed by 5- to 7-foot northwesterly sea and swell (with a 5- to 11-second period) on Friday into next Sunday.

Combined with this northwesterly sea and swell will be a 1- to 2-foot southern hemisphere swell (with a 15- to 17-second period) on Saturday through Sunday, building to 2 to 3 feet with the same period on Monday through the upcoming week.

Seawater temperatures will range between 50 and 53 degrees through next Sunday.

On this date in weather history (June 2):

1917: The temperature at Tribune, Kansas, dipped to 30 degrees to establish a state record for the month of June.

1949: A tornado northeast of Alfalfa, Oklahoma, circled an area one mile in radius. (The Weather Channel)

1985: Lightning struck a house, broke a bedroom window, and jumped to a metal frame bed. A man was killed, but his wife was unharmed by the lightning. ((The Weather Channel)

2016: The Paso Robles Airport reached 100 degrees, the first 100-degree reading of the year, while at the same time, Diablo Canyon reported a high of 58 degrees.

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.

This story was originally published June 2, 2024 at 5:00 AM.