Weather Watch

SLO County weather forecast for the week of Aug. 11

An upper-level low-pressure system off the California coast will bring cooler temperatures to the Central Coast. Monsoonal moisture will continue to be drawn northward by the upper-level low and result in increased thunderstorm activity across the Sierra and variable mid- to high-level clouds across San Luis Obispo County. Some smoke from the Northern California wildfires may also drift over our area.

This morning’s deep marine layer is expected to produce a few pockets of mist/drizzle along the beaches and coastal valleys. The marine low cloud cover will linger into early afternoon along the beaches, giving way to partly cloudy skies.

Maximum temperatures in the North County will reach the low 90s. The coastal valleys will reach the mid-70s, while the beaches will remain in the 60s.

The monsoonal moisture is forecast to move off to the east by Wednesday. Otherwise, little change in this pattern is expected through Friday. High pressure will build and produce warmer temperatures by this weekend.

Surf report

Arriving from the northwest: A 3- to 5-foot northwesterly (310-degree, deep-water) swell (with a 7- to 9-second period) is expected to develop along the San Luis Obispo County coastline today.

A 3- to 5-foot northwesterly (315-degree, deep-water) sea and swell (with a 5- to 20-second period) is set to arrive Tuesday, increasing to 4 to 6 feet (with a 6- to 17-second period Wednesday into Thursday. This swell will decrease to 3 to 5 feet (with a 7- to 15-second period) Friday into Saturday.

Arriving from the south: Today’s 1- to 2-foot Southern Hemisphere (180-degree, deep-water) swell (with a 15- to 17-second period) will remain at this height but with a gradually shorter period through Tuesday.

Model runs are still indicating a large storm developing southwest of New Zealand on Friday. If the storm develops as advertised, a moderate-energy Southern Hemisphere swell will arrive along our coastline around Aug. 23 and 24. 

Seawater temperatures

Seawater temperatures are forecast to range from 58 to 63 degrees through Saturday.