Here is this week’s weather forecast by PG&E meteorologist John Lindsey.
A 1,008-millibar low-pressure system off the Central Coast is forecast to move northward toward San Francisco over the next 24 hours. This system will produce gentle to moderate (8- to 18-mph) southerly winds and marine low clouds with areas of fog and drizzle in the coastal regions of San Luis Obispo and Santa Barbara counties.
Monday’s high temperatures will range from the low 80s in the North County to the low 70s in the coastal valleys, while the beaches will remain in the 60s. The winds are expected to shift out of the northwest Tuesday. This onshore flow will continue to produce marine low clouds and fog with areas of mist during the night to morning hours.
An upper-level low-pressure system is forecast to develop off the California coast Wednesday.
If this late-season low-pressure system is strong enough, it will produce much lower temperatures, strong to gale-force (25- to 38-mph) northwesterly winds along the coastline. This system will also produce the possibility of rain showers and even thunderstorms, especially over the higher terrain, Wednesday night into Thursday, when this system moves inland over the Central Coast.
Another round of rain showers and the chance for thunderstorms are possible Friday into Sunday, with precipitation falling as snow in the Sierra Nevada above 7,000 feet. The unsettled weather will end by next Monday, as the last low-pressure system finally moves east of San Luis Obispo and Santa Barbara counties. A high-pressure ridge is expected to build back over California early next week for a return to fair and warmer weather.
A 4- to 6-foot northwesterly (290-degree, deep-water) swell (with an 8- to 13-second period) is forecast along our coastline Monday into Tuesday. Combined with Monday and Tuesday’s northwesterly swell will be a 2- to 3-foot Southern Hemisphere (190-degree, deep-water) swell (with a 15- to 17-second period).
Increasing northwesterly winds will generate a 4- to 6-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 12-second period) on Wednesday, increasing to 7 to 9 feet (with a 5- to 11-second period) on Thursday. This northwesterly sea and swell will further build to 8 to 10 feet Friday. A 5- to 7-foot northwesterly (290-degree, deep-water) swell (with an 8- to 15-second period) is forecast along our coastline Saturday into Sunday.
Seawater temperatures are expected to range between 53 and 56 degrees through Wednesday, decreasing to 50 to 54 degrees Thursday into Friday.
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At PG&E, your safety is our first concern. Thunderstorms may develop later this week. Lightning kills an average of 49 people in the United States each year, and hundreds more are severely injured. There is no safe place outside when thunderstorms are in the area.
If you hear thunder, you are likely within striking distance of the storm.
Just remember: “When thunder roars, go indoors.”
This week’s temperatures
LOWS AND HIGHS, PASO ROBLES
LOWS AND HIGHS, SLO AND COASTAL VALLEYS