SLO County in for a wet and windy Thanksgiving week. Here’s the forecast

A cold front was expected to sweep through the Central Coast on Saturday morning, bringing fresh to strong (19 to 31 mph) southerly winds and moderate rainfall. Total rainfall was expected to range from 0.25 to 0.75 of an inch on Saturday.

From Saturday afternoon through Monday morning, partly to mostly cloudy skies will prevail, with moderate to fresh (13 to 24 mph) southerly winds and the possibility of scattered rain showers.

A prolonged period of wet weather is anticipated from Monday afternoon through Thanksgiving Day.

The 96-hour surface chart indicates a blocking high over the Gulf of Alaska, with two low-pressure systems advancing toward Central California: one about 1,000 miles west of the Central Coast and another 1,000 miles farther west.

The first storm will bring strong to gale force (25 to 38 mph) southerly winds from Monday evening through Tuesday morning as the frontal system moves through.

Winds will subside by Tuesday afternoon, transitioning the rain into scattered showers through Tuesday night. Rainfall totals from this system are expected to range between 0.5 and 1.25 inches.

On Wednesday, an occluded front will move over the region, producing gentle to moderate (8 to 18 mph) westerly winds accompanied by heavy drizzle and light rain.

Rainfall amounts are projected between 0.30 and 0.50 of an inch.

The second low-pressure system and associated cold front will pass through the Central Coast on Thanksgiving Day, bringing moderate to fresh (13 to 24 mph) southerly winds and additional rainfall. Rainfall amounts on Thursday are forecast to range between 0.50 inches and 1 inch.

Overall, cumulative rainfall from Monday afternoon through Thursday is expected to total 1.5 to 3.0 inches, with higher amounts likely in the Santa Lucia Mountains due to orographic lift.

Over the period, temperatures are expected to remain mild.

Temperatures in inland valleys (Paso Robles), coastal valleys (San Luis Obispo) and beaches will drop to the high 40s during the overnight and reach the high 50s to low 60s during the afternoon.

Santa Lucia winds (northeasterly) and clear skies are expected by Friday, lasting into the weekend.

Clear skies will allow temperatures to drop to the mid-30s to low 40s with highs reaching into the low 70s.

Surf report

A 4-to 6-foot westerly (265-degree deep water) swell (with an 8-to 13-second period) is forecast along our coastline through Monday.

Increasing southerly winds will generate 5-to 7-foot southwesterly seas (with a 4-to 8-second period) on Tuesday, followed by a 3-to 5-foot westerly sea and swell (with a 7-to 14-second period) on Wednesday into next Saturday.

Combined with this westerly sea and swell will be a 1- to 3-foot southern hemisphere swell (with a 17- to 20-second period) on Thursday into Friday.

Surface seawater temperatures will range between 53 and 55 degrees through Tuesday, warming to 55 to 57 degrees on Wednesday through next Saturday.

On this date in weather history

1812: Hurricane-force, southwesterly winds sank ships and blew the roofs off of buildings in Philadelphia and New York City. (David Ludlum)

1863: The Civil War “battle above the clouds” was fought on Lookout Mountain near Chattanooga, Tennessee. Pre-frontal clouds obscured the upper battlefield, aiding a Union victory. (David Ludlum)

2017: For the third day in a row, San Luis Obispo and Paso Robles broke high temperature records. Both the San Luis Obispo and Paso Robles airports hit 87 degrees on Thanksgiving Day, breaking SLO’s old record of 85 degrees in 1954, and Paso Robles’ record of 79 degrees in 2005.

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.