Weather Watch

SLO County weather forecast for the week of March 18

Here is this week’s weather forecast by PG&E meteorologist John Lindsey.

Weather report

Weak high pressure will build over the Central Coast today and will yield generally fair and dry conditions through Tuesday afternoon.

A shift to wet weather will unfold Tuesday night as a relatively warm system begins to move into San Luis Obispo County from the Pacific. Initial shower activity will spread across the Central Coast on Tuesday night while a band of heavier showers will follow Wednesday.

Overall, the weak storm system and associated cold front will produce less than a quarter inch of rain. Snow levels in the Sierra will lower to about 5,000 feet by Wednesday afternoon, with new snow accumulations of 3 to 8 inches possible above 6,500 feet.

Residual moisture will produce areas of fog Wednesday night into Thursday morning, giving way to partly cloudy skies. High pressure will build rapidly over California and produce strong to gale force (25- to 38-mph) northwesterly winds along the coast during the afternoon.

This high pressure ridge will also signal the return of gentle to moderate (8- to 18-mph) and at times gusty northeasterly (Santa Lucia) winds during the night and morning. These winds will produce fair and dry conditions with temperatures remaining well above normal for the start of spring Wednesday. Dry weather then should persist through the weekend and into the following week.

Surf report

Today’s 4- to 6-foot northwesterly (290-degree deep-water) swell (with an 8- to 13-second period) will decrease to 3 to 5 feet (with an 8- to 12-second period) Tuesday. This northwesterly swell will further lower to 2 to 4 feet Wednesday.

Strong to gale force (25- to 38-mph) northwesterly winds along the coast will produce an 8- to 10-foot northwesterly (310-degree deep-water) sea and swell (with a 5- to 9-second period) Thursday.

An 8- to 10-foot northwesterly (295-degree deep-water) sea and swell (with a 7- to 20-second period) will arrive along the coast Friday, decreasing to 6 to 8 feet (with an 8- to 17-second period) Saturday and Sunday.

Arriving from the Southern Hemisphere: A 1- to 2-foot Southern Hemisphere (195-degree deep-water) swell (with a 19- to 21-second period) will arrive along the Pecho Coast on Saturday. This swell will remain at this height but with a shorter interval through Sunday.

Seawater temperatures

Seawater temperatures will range between 50 and 52 degrees through March 25.