SLO County weather forecast: Colder — with chance of scattered rain showers

Batten down the hatches! A prolonged period of relentless gale-force northwesterly winds will produce mostly clear skies (except for haze), blowing sand in the coastal regions and below seasonal temperatures. In other words, it will be cold and windy for much of this week.

These spring gales will continue through Thursday as a 1,036 millibar Eastern Pacific High remains firmly anchored off Northern California and a series of low-pressure systems move southward down the California coastline. This condition will produce a pattern of moderate gale-force to fresh gale-force (32 to 46 mph with gusts to 55+ mph) northwesterly winds during the afternoon along the coastline, decreasing and shifting out of north-northwest during the night and morning.

A late-season low-pressure system will rotate through Central California on Monday into Tuesday, resulting in variable amounts of mid to high-level clouds. More importantly, it will also bring a cooler air mass to the Central Coast with the inland valleys (Paso Robles) only reaching the mid-60s, while the coastal valleys (San Luis Obispo) will struggle to get out of the 50s on Monday and Tuesday with overnight lows in the mid-30s. The gale-force northwesterly winds will make it feel even colder.

An upper- level trough could produce increasing clouds and a few scattered rain showers and gale-force northwesterly winds on Wednesday into Thursday.

A return to fair and much warmer weather looks likely next weekend as high pressure builds over California. The inland valleys are forecast to reach the low-90s, while the coastal valleys will hit the mid-80s.

Surf report

An 11- to 13-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 13-second period) is forecast through Sunday.

This northwesterly sea and swell will lower to 6- to 8-feet (with a 7- to 11-second period) on Monday and will remain at this level through Friday.

Arriving from the Southern Hemisphere, a 2- to 3-foot (215-degree, deep-water) swell (with a 14- to 16-second period) will remain at this height but with a gradually shorter period through Monday.

Seawater temperatures range between 48 and 50 degrees through Friday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

PG&E safety tip

This week’s gale-force winds could cause downed trees or branches that could be hiding a power line. Always assume all wires are energized and extremely dangerous. Don’t touch or try to move it. Keep children and animals far away. Report downed lines to 911 and PG&E at 1-800-743-5002.

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 May 8, 2022 at 5:00 AM.