Get cozy, SLO County. The weather forecast calls for cooler temperatures

Pick up some hot chocolate and get cozy, San Luis Obispo County — the weather is about to get a bit chillier.

On Tuesday, the ridge of high pressure over California that brought Santa Lucia (northeasterly) winds, clear skies and near record-breaking warmth across the Central Coast will begin to weaken.

As it does, the prevailing wind flow will shift out of the northwest, allowing marine stratus clouds to redevelop in the coastal regions later on Tuesday. These clouds are expected to persist through Friday, accompanied by a cooling trend.

Moderate to fresh (13 to 24 mph) Santa Lucia (northeasterly) winds will develop overnight into the morning, then ease during the afternoon. This pattern will persist through Tuesday morning, bringing cool, crisp mornings followed by mild afternoons.

Overnight low temperatures through Monday will fall into the lower 40s in the inland valleys, including Paso Robles, and into the low 50s along the beaches and in the coastal valleys such as San Luis Obispo.

Daytime high temperatures across the Central Coast will reach the low to mid-70s during the Martin Luther King Jr. holiday weekend.

By Tuesday afternoon, winds will shift out of the northwest and remain onshore (from the sea to the land) through the remainder of the workweek.

This transition will allow low marine clouds to redevelop along the coast and into the coastal valleys during the night and morning, with areas of fog and mist.

Marine stratus will clear from the coastal valleys during the afternoon but will remain more persistent along the beaches.

Coastal areas will experience milder overnight temperatures but cooler daytime highs due to increased cloud cover. In contrast, inland valleys will see colder nights and warmer daytime temperatures.

A weak low-pressure system is expected to move through the region from Friday into early Saturday, bringing increasing cloud cover and a few scattered light rain showers across San Luis Obispo and Santa Barbara counties. Any measurable rainfall is expected to remain below one-tenth of an inch.

Looking ahead, another round of Santa Lucia northeasterly winds is anticipated during the early part of the following week, with an additional chance of rain around Jan. 30 and 31.

Surf report

A 2- to 4-foot northwesterly (290-degree, deep water) swell (with a 12- to 18-second period) will increase to 3 to 5 feet (with an 11- to 16-second period) on Sunday and will remain at level through Friday.

Increasing northwesterly winds will generate a 4- to 6-foot northwesterly (305-degree, deep water) sea and swell (with a 5- to 15-second period next Saturday and Sunday.

Seawater temperatures will range between 58 and 60 degrees through Friday, lowering to 57 to 59 degrees next Saturday and Sunday.

On this date in weather history (Jan. 18)

1990: A winter storm produced heavy snow and high winds across the southwestern United States. Snowfall totals ranged up to 18 inches at Lake Arrowhead, California, and Ashford, Arizona. High winds in New Mexico gusted to 100 mph east of Albuquerque. (David Ludlum)

2006: A cold front produced 0.09 inches of rain at the Diablo Canyon Ocean Lab. An upper-level trough crossing California continued to produce isolated rain showers with numerous rainbows throughout our area and thunderstorms over the Central Valley with frequent lightning strikes.

2008: The relaxation of the northeasterly (offshore) winds and clear skies produced cold temperatures, with many of our areas reaching below the freezing point.

2019: The westerly swell at the Diablo Canyon waverider buoy peaked at 17.2 feet with an 18-second period at 3 p.m. The Santa Lucia Escarpment waverider buoy about 45 miles to the southwest of Diablo Canyon reached 25 feet with an 18-second period at 4 p.m., while the Cape San Martin NOAA buoy peaked at 24 feet.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

SUNDAY: 41, 72

MONDAY: 40, 71

TUESDAY: 49, 71

WEDNESDAY: 42, 67

THURSDAY: 40, 65

FRIDAY: 39, 64

SATURDAY: 40, 65

SUNDAY: 42, 67

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

SUNDAY: 53, 77

MONDAY: 50, 72

TUESDAY: 50, 71

WEDNESDAY: 52, 67

THURSDAY: 53, 66

FRIDAY: 50, 64

SATURDAY: 51, 62

SUNDAY: 52, 64

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