San Luis Obispo County weather forecast for the week of Oct. 12

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

Monday morning’s patchy areas of coastal low clouds and fog will clear from the beaches by the afternoon. Otherwise, high pressure is expected to build over the Central Coast on Monday and keep San Luis Obispo County in a warming trend in which temperatures will be about 10 and 15 degrees above normal.

Monday’s high temperatures are expected to reach the high 90s in the North County and low 90s in the coastal valleys. The beaches will range from the high 60s to the high 70s. A few areas of low clouds and fog will develop along the beaches Monday night into Tuesday morning. Overnight temperatures will dip to the high 50s and 60s, which will help mitigate the warm temperatures.

A change in the weather pattern will develop later Tuesday as increasing subtropical moisture will bring warmer overnight lows and muggy conditions. This moisture is associated with an upper-level low-pressure system over Baja that will move toward Southern California. This subtropical flow will produce variably cloudy skies, sprinkles and a chance of rain showers late Tuesday into Thursday. Thunderstorms may also develop in the far eastern regions of San Luis Obispo County and over the Santa Lucia Mountains. These mid- to high-level sub-tropical clouds will also bring the promise of spectacular sunrises and sunsets.

Increasing northwesterly winds later Friday into next Monday will produce night and morning low clouds and fog along the beaches and cooler temperatures along the immediate coastline. Marine air will filter into the coastal valleys Saturday and into the North County by Sunday, bringing cooler temperatures. Some of the numerical models are advertising a passage of a low pressure trough next Monday; however, details regarding the strength and timing remain very unclear at this time.

Monday’s surf report

Monday’s 5- to 7-foot northwesterly (290-degree, deep-water) swell (with an 11- to 20-second period) will decrease to 4 to 6 feet (with an 11- to 17-second period) on Tuesday, further lowering to 3 to 5 feet (with an 11- to 14-second period) on Wednesday into Thursday.

Increasing northwesterly winds will generate a 3- to 5-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 12-second period) on Friday into Saturday, building to 5 to 7 feet (with a 5- to 13-second period) Sunday into next Monday.

Arriving from the Southern Hemisphere

A 1- to 2-foot Southern Hemisphere (220-degree, deep-water) swell (with an 18- to 20-second period) will arrive Monday and will remain at this height but with a gradually shorter period through Wednesday.

Seawater temperatures

Abnormally warm seawater temperatures will continue along the coastline through Thursday. Seawater temperatures will range between 61 and 65 degrees through Tuesday, rising to 62 and 66 degrees on Wednesday into Thursday. Seawater temperatures are expected to decrease Friday through next Monday.

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At PG&E, your safety is our first concern. With the possible thunderstorms later this week, please remember that 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. Remember: “When thunder roars, go indoors.”