Here is this week’s weather forecast by PG&E meteorologist John Lindsey.
Daily maximum temperature records were broken in San Luis Obispo and Paso Robles during the weekend. San Luis Obispo reached 103 degrees about 11 a.m. before the northwesterly (onshore) winds produced cooling during the afternoon Saturday. The previous record was 97 degrees set in 1956. Paso Robles hit 111 degrees about 5 p.m. Saturday, which broke a record temperature of 109 degrees set June 29, 1994.
Along the coast, strong to gale-force (25- to 38-mph) afternoon northwesterly winds produced a large temperature gradient from north to south Saturday afternoon. Los Osos hit a high of only 66 degrees, while both Diablo Canyon and the Point Luis Lighthouse reached 92 degrees. Farther south, Avila Valley at the PG&E Energy Education Center hit 108 degrees.
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Today’s persistent northwesterly (onshore winds) have produced dramatically lower temperatures along the beaches and in the coastal valleys. As of 3 p.m. Sunday, Diablo Canyon had reached a high of 59 degrees, while the Point San Luis Lighthouse hit a comfortable 73 degrees. Los Osos had reached only a high of 62 degrees and Avila Valley 89 degrees.
Cal Poly (home of record for climatology in San Luis Obispo) reached a high of 90 degrees at 10:45 a.m. Sunday. San Luis Obispo County Regional Airport hit a high of 88 degrees about noon Sunday, while sloweather .com in western San Luis Obispo reached 86 degrees at 11:15 a.m.
In the North County, it’s been a different story. As of 4 p.m. Sunday, Paso Robles Municipal Airport reached 108 degrees, which was another daily record high. The previous record was 107 degrees set in 1996.
There is no relief from the heat expected in the North County through Thursday, with temperatures reaching the triple-digit level.
Temperatures in coastal valley regions such as San Luis Obispo will reach the high 80s today through Wednesday. At the beaches, temperatures will range between the low 60s to high 60s today and Tuesday, with areas of night and morning low clouds and fog.
One other wrinkle to the forecast will be subtropical moisture streaming northward Tuesday and Wednesday, which will increase the humidity, raise the overnight minimums because of cloud cover, and increase the afternoon thunderstorms over the Sierra Nevada.
The high-pressure ridge responsible for the high North County temperatures will weaken and the marine layer will deepen along the coast by Wednesday night. The cloud ceiling should be high enough for good Fourth of July fireworks display viewing Thursday. Temperatures will continue to cool through next week.
Today’s 3- to 5-foot northwesterly (290-degree deep-water) swell (with an 8- to 11-second period) will remain at this height and period through Wednesday.
Increasing northwesterly winds will generate a 4- to 6-foot northwesterly (300-degree deep-water) sea and swell (with a 5- to 9-second period) along the coast Thursday and will remain at this height and period through Sunday.
Seawater temperatures will range from 51 to 54 degrees today, increasing to 53 to 56 degrees Tuesday through Thursday.