Next SLO County storm will bring rain and colder temperatures, with snow down to 2,500 feet

Unlike recent storms, which tapped into subtropical moisture and produced mild temperatures, this week’s low-pressure systems will be much colder in nature as the northerly upper-level winds bring in a frigid air mass.

Daytime temperatures for this upcoming week will remain 10 to 15 degrees below normal.

A few scattered rain showers, strong to gale-force (25 to 38 mph) northwesterly winds and cold temperatures with snow levels down to 2,500 feet are expected Sunday morning. Partly cloudy to mainly clear skies and dry and cold conditions are forecast for Sunday afternoon and night.

Sunday’s high temperatures will remain in the 50s. On Monday, a cold front will produce moderate gale-force to fresh gale-force (32 to 46 mph) southwesterly winds, rain and low elevation snow. At this time, between 0.75 and 1.25 inches of rain are forecast on Monday, with snow levels at 2,000 feet.

Heavy snow is forecast in the Sierra Nevada mountain range. Along the Central Coast, high temperatures will range between the high 40s and low 50s on Monday.

Dry, cold, and mostly clear conditions are forecast on Tuesday, with overnight lows reaching below or near freezing throughout the Central Coast.

The late great meteorologist Dr. George Fischbeck — who appeared on KABC-TV Channel 7 in Los Angeles during the 1970s and ‘80s — coined the insightful phrase, “A cutoff low is a weatherman’s woe.”

A cutoff low pressure system is forecast to develop off the Central California coastline Tuesday night into Thursday, the last day of 2021.

At this time, the models do not agree on the track of this storm system. Consequently, rainfall amounts are all over the map, ranging from a few hundredths of an inch to several inches of rain. If we receive precipitation from the weather system, snow levels could reach 1,500 feet.

Surf report

Seawater temperatures will range from 55 to 57 degrees throughout this week.

A 6- to 8-foot west-northwesterly (285-degree, deep water) swell (with an 8- to 13-second period) is expected along our coastline on Sunday.

Moderate gale-force to fresh gale-force (32 to 46 mph) southwesterly winds will generate a 7- to 9-foot southwesterly (250-degree, deep water) sea and swell (with a 5- to 12-second period) on Monday. The swell will decrease to 5 to 7 feet by Tuesday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

PG&E safety tip

The abundance of moisture combined with the cold temperatures could create black ice and slick spots on our roads, especially on overpasses and bridges. Black ice forms when temperatures fall below 32 degrees in areas that recently received rain, snow or slush. Slowing down is the most important thing when driving on ice and snow.

John Lindsey’s is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at pgeweather@pge.com or follow him on Twitter @PGE_John.

This story was originally published December 26, 2021 at 5:00 AM.