Get ready for some perfect spring days, SLO County. See this week’s forecast
Gale-force northwesterly winds, clear skies and mild temperatures are expected this weekend.
Winds will rapidly diminish on Monday through next weekend, allowing areas of marine low clouds and fog to redevelop along the coast during the night and morning hours, along with near-seasonal temperatures.
A strong 1,033-millibar Eastern Pacific high-pressure system, centered about 600 miles west of Cape Mendocino, combined with a dry cold front inland, will create a steep pressure gradient across California. As a result, moderate gale-force to fresh gale-force (32 to 46 mph, with gusts exceeding 55 mph) northwesterly winds are forecast this weekend.
These powerful winds will be strong enough to mix out the marine inversion layer, leaving behind mostly clear skies. Meanwhile, the upper-level jet stream flowing out of the northwest will usher in a cooler air mass, helping to keep temperatures relatively mild despite the sunshine.
Daytime highs are expected to reach the mid-80s across inland valleys, including Paso Robles, while coastal valleys such as San Luis Obispo will warm into the mid- to upper 70s. Along the beaches, temperatures will generally range from the upper 50s to low 60s.
However, south-facing beaches such as Cayucos, Avila Beach, and Shell Beach could see highs climb into the mid-70s this weekend.
A trough of low pressure will develop along the Central and Southern California coastline, causing the northwesterly winds to ease to gentle to moderate levels (8 to 18 mph). Winds will generally remain out of the west-northwest through the upcoming workweek, except for Monday morning when offshore northeasterly (Santa Lucia) winds are expected.
This weather pattern will allow areas of low marine clouds, along with pockets of mist and fog, to form during the night and morning across the coastal regions from Monday night through next Sunday. Otherwise, clear skies with occasional variable mid- and high-level cloudiness streaming overhead will persist through next weekend.
Meanwhile, the jet stream will continue to flow out of the Gulf of Alaska toward the Central Coast, maintaining relatively mild temperatures near seasonal averages.
Daytime highs are expected to reach the mid-80s across the inland valleys, while coastal valleys warm into the mid- to upper 70s.
Along the beaches, however, frigid seawater temperatures will keep conditions cool, with daytime highs generally ranging from the upper 50s to lower 60s.
Looking farther ahead, forecast models continue to indicate a return of gale-force northwesterly winds along the coastline, while temperatures remain relatively mild.
Surf report
A 13- to 15-foot northwesterly (310-degree deep-water) sea and swell (with a 5- to 11-second period) is expected this Saturday through Sunday.
Gentle to moderate (8 to 18 mph) northwesterly winds along the Central and Southern California coastline will allow a 5- to 7-foot northwesterly (295-degree deep-water) swell (with a 7- to 12-second period) to develop Monday, decreasing to 4- to 6-feet (with an 8-to 15-second period) on Tuesday.
This northwesterly swell will further lower to 3- to 5-feet (with an 8- to 13-second period) on Wednesday and remain at this level through next weekend.
Northwesterly gales and high northwesterly seas are forecast throughout the following week.
Arriving from the Southern Hemisphere: A 2- to 4-foot Southern Hemisphere (205-degree deep-water) swell (with a 16- to 18-second period) is forecast to arrive along the Central Coast on the 25th through the 30th of May.
Seawater temperatures:
Intense ocean upwelling will drive seawater temperatures down to a frigid 48 to 50 degrees along the immediate coastline this weekend through Monday.
Seawater temperatures will gradually warm through the work week, reaching between 52 and 54 degrees by next weekend.
On this date in weather history
1979: A reading of 12 degrees at Mauna Kea Observatory established an all-time record low for the state of Hawaii. (The Weather Channel)
1983: A golfer playing the Fox Meadows Course in Memphis, Tennessee, was struck by a bolt of lightning that went through his neck, down his spine, came out a pocket containing his keys and went into a nearby tree. Miraculously, he survived!
1988: A “thunderstorm of a lifetime” in northern Spartanburg County, South Carolina, produced hail for 45 minutes, leaving some places knee-deep in hail. (The National Weather Summary) (Storm Data)
2020: A band of light-to-moderate rain moved through the Central Coast and San Luis Obispo County. My home in Los Osos recorded 0.12 of an inch.
This week’s temperatures
LOWS AND HIGHS, PASO ROBLES
SUNDAY: 45, 83
MONDAY: 46, 83
TUESDAY: 49, 85
WEDNESDAY: 50, 88
THURSDAY: 49, 87
FRIDAY: 50, 88
SATURDAY: 51, 87
SUNDAY: 49, 86
LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS
SUNDAY: 49, 70
MONDAY: 52, 78
TUESDAY: 53, 77
WEDNESDAY: 55, 79
THURSDAY: 55, 78
FRIDAY: 55, 77
SATURDAY: 54, 78
SUNDAY: 55, 79
John Lindsey is a retired PG&E marine meteorologist. Email him at JohnLindseyLosOsos@gmail.com or follow him on X @PGE_John.