Patchy fog, windy weather in the forecast for Halloween week in SLO County

From Sunday through Wednesday, gusty Santa Lucia (northeasterly) winds will develop overnight and into the morning. The wind will shift out of the northwest in the afternoon, producing primarily clear skies and mild temperatures.

An intense storm system will move into the Pacific Northwest this weekend, bringing significant rain and high-elevation snow as far south as the San Francisco Bay Area.

However, the associated cold front will weaken considerably as it moves southward, resulting mainly in increasing cloud cover, along with pockets of mist and drizzle over the Central Coast on Saturday.

High pressure over the Great Basin, combined with the Eastern Pacific High offshore, will generate moderate to fresh (8- to 18-mph, occasionally gusty) Santa Lucia (northeasterly) winds during the night and morning, followed by fresh to strong (19- to 31-mph) northwesterly winds each afternoon beginning Sunday and continuing through Wednesday.

This pattern will create primarily clear skies, except for some stratus clouds along the ridge tops of the Santa Lucia and coastal mountains, and generally mild temperatures.

Interestingly, this time of year often brings warmer conditions along the beaches than in the inland valleys. In fact, weather for the 46th annual Oktoberfest in Baywood Park on Sunday should be beautiful.

Afternoon high temperatures will range from the mid-70s in the inland valleys (around Paso Robles), to the upper-70s in the coastal valleys (San Luis Obispo), and similar temperatures along the beaches.

Persistent northwesterly winds developing late Wednesday and lasting through next Saturday will allow low marine clouds to form along the coast, moving inland overnight and during the morning hours, with patches of fog and drizzle. These clouds will generally clear by late morning or early afternoon.

Daylight Saving Time ends on Sunday, Nov. 2, at 2 a.m., when clocks are set back one hour — the annual “fall back” to Pacific Standard Time.

Looking ahead, the next chance for increasing southerly winds and rain is forecast around Nov. 8.

Surf report

A 6- to 8-foot northwesterly (305-degree, deep water) sea and swell (with a 5- to 14-second period) is forecast along our coastline through Monday morning, decreasing to 5 to 7 feet (with a 7- to 12-second period) Monday afternoon through Tuesday.

A 6- to 8-foot northwesterly (300-degree, deep water) sea and swell (with a 5- to 15-second period) is forecast on Wednesday and will remain at this level through next Saturday.

A 1- to 3-foot southerly (205-degree, deep water) swell (with a 19- to 21-second period) will arrive on Friday, peaking at 2 to 3 feet (with an 18- to 20-second period) next Saturday and Sunday.

Seawater temperatures will range between 56 and 58 degrees through next Saturday.

On this date in weather history (Oct. 26)

1919: The temperature at Bismarck, North Dakota, plunged to 10 degrees below zero, the earliest subzero reading on record for the city, and a record for the month of October.

2004: An intense cold front moved through the Diablo Canyon nuclear power plant area that morning, bringing heavy rain and occasional lightning. The system produced a total of 1.90 inches of precipitation, with nearly 1.1 inches falling between 9:15 and 9:45 a.m. During that period, air temperatures dropped by almost 8 degrees.

2007: The full moon on Oct. 25-26 was the largest and brightest of 2007 — and that was no optical illusion. Some full moons truly appear larger than others, and Thursday night’s moon was up to 14% wider and 30% brighter than the smaller full moons seen earlier this year. Because the moon’s orbit is elliptical, one side comes about 30,000 miles closer to Earth than the other. This month’s full moon occurred at perigee — the point closest to Earth — making it noticeably bigger and more luminous.

2020: The anemometer atop Chair 6 Ridge on Kirkwood Mountain, at an elevation of 9,186 feet south of Lake Tahoe, recorded sustained east-northeasterly winds of 110 mph and gusts reaching 136 mph early that morning. Meanwhile, an anemometer on Mount Saint Helena — which spans the flanks of Napa, Sonoma and Lake counties in California — measured northeasterly wind gusts up to 89 mph.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

SUNDAY: 48, 71

MONDAY: 44, 74

TUESDAY: 46, 75

WEDNESDAY: 47, 76

THURSDAY: 49, 77

FRIDAY: 48, 75

SATURDAY: 47, 74

SUNDAY: 48, 75

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

SUNDAY: 56, 72

MONDAY: 55, 75

TUESDAY: 54, 76

WEDNESDAY: 54, 78

THURSDAY: 55, 77

FRIDAY: 54, 78

SATURDAY: 54, 77

SUNDAY: 53, 78

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