Windy weather will follow the rain in SLO County. Here’s the forecast

A late-season storm will bring gusty southerly winds, periods of rain and scattered thunderstorms through Sunday.

The storm will be followed by a prolonged stretch of gale-force northwesterly winds beginning Monday and continuing through the following week — a classic Central Coast spring weather pattern.

A 533-decameter, upper-level, low-pressure system just off the California coast, along with its associated cold front sweeping across the Central Coast from Saturday afternoon into Sunday morning, will bring strong to gale-force (25 to 38 mph) southerly winds and periods of rain.

With the longer daylight hours of April, much colder air tied to this upper-low will enhance atmospheric instability, increasing the likelihood of thunderstorms. These convective cells could produce periods of heavy rain, hail, localized microbursts, and even a slight chance of funnel clouds, waterspouts or a weak tornado.

An upper-level trough will follow on Sunday afternoon and night with scattered rain showers and cool temperatures. In fact, daytime temperatures will struggle to reach the 60s throughout the Central Coast on Sunday.

Total rainfall this weekend is expected to range between 0.75 and 1.25 inches, with higher amounts in the Santa Lucia and Coastal Mountains due to orographic enhancement.

A strong 1,030-millibar Eastern Pacific high will build about 700 miles west of Cape Mendocino on Monday and remain nearly stationary, creating a steep pressure gradient along the California coastline. This setup will produce strong to gale-force (25 to 38 mph, with gusts up to 45 mph) northwesterly winds during the afternoon and evening.

Winds will ease overnight and into the morning, allowing areas of low marine clouds to form along the coast.

A dry cold front is expected to move through the Central Coast on Thursday, bringing the potential for even stronger northwesterly winds, ranging from moderate gale-force to fresh gale-force (32 to 46 mph, with gusts up to 55 mph) levels on Thursday afternoon and evening.

During this period, high temperatures will reach the low to mid-70s in the inland valleys, including Paso Robles, and the high 60s to low 70s in the coastal valleys, such as San Luis Obispo.

Beach temperatures will generally range between high 50s to the low 60s, except for south-facing locations like Cayucos, Avila Beach and Shell Beach, where highs could reach the low 70s.

Looking ahead, dry and windy conditions are expected to persist through the end of April.

Surf report

Increasing southerly winds will generate a 5- to 7-foot westerly (265-degree, deep water) sea and swell (with a 5- to 13-second period) on Saturday afternoon into Sunday morning, building to 6 to 8 feet on Sunday afternoon through Monday morning.

Increasing northwesterly winds along the California coastline will generate 5- to 7-foot northwesterly (290-degree, deep water) sea and swell (with a 5- to 11-second period) on Monday afternoon through Wednesday, increasing to 8 to 10 feet with the same period on Thursday.

A 5- to 7-foot northwesterly (300-degree, deep water) sea and swell (with a 5- to 11-second period) is forecast on Friday into the following week.

Combined with this sea and swell will be a 1- to 3-foot Southern Hemisphere (210-degree, deep water) swell, with a 14- to 16-second period on Saturday through Monday.

Seawater temperatures are expected to range between 55 and 57 degrees through Monday.

Gale-force northwesterly winds along the California coastline will enhance coastal upwelling, leading to progressively cooler ocean temperatures.

From Tuesday through Wednesday, seawater temperatures will drop to 52 to 54 degrees, then cool further to 50 to 52 degrees by Thursday, where they are expected to remain at this level through the following week.

On this date in weather history (April 12)

1934: Winds atop Mount Washington, New Hampshire, averaged 186 mph for five minutes, with a peak gust of 231 mph — the highest wind speed ever recorded in the world. (David Ludlum)

1988: While snow blanketed the Southern Appalachians, Mitchell County, North Carolina recorded about 17 inches of show. Winds at Flat Top Mountain gusted to 80 mph. (Storm Data)

2010: A strong cold front, especially for mid-April, passed the Central Coast on April 11, producing extremely strong winds and periods of heavy rainfall. Many locations in the county received more rain over this 24-hour period than they would normally receive during the entire month of April (about 1.7 inches). One-inch diameter hail was reported in Fresno, and two condominiums were destroyed by thunderstorms in the San Joaquin Valley. Up to three funnel clouds were also seen in the region.

2022: The Diablo Canyon Meteorological Tower reported sustained northwesterly winds of 42 mph with gusts to 55 mph in the morning, with many coastal communities experiencing lower temperatures than the coastal and inland valleys. Los Osos reported 37 degrees, while Paso Robles was at 39 degrees and the San Luis Obispo County Regional Airport at 45 degrees. Mt. Lowe on the Cuesta Grade was at 32 degrees with gusts up to 44 mph, producing a wind chill of 15 degrees!

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

SUNDAY: 45, 60

MONDAY: 39, 65

TUESDAY: 40, 72

WEDNESDAY: 41, 76

THURSDAY: 43, 72

FRIDAY: 45, 71

SATURDAY: 47, 75

SUNDAY: 47, 76

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

SUNDAY: 50, 59

MONDAY: 45, 64

TUESDAY: 46, 68

WEDNESDAY: 48, 73

THURSDAY: 51, 68

FRIDAY: 50, 70

SATURDAY: 53, 72

SUNDAY: 54, 72

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