SLO County weather forecast for the week of July 4: Morning fog, then clear skies

Much like most of last week, a 1,500-foot deep marine layer with areas of fog and mist covers all the beaches and coastal valley and a few of the inland areas this Fourth of July morning. The coastal stratus will clear from the inland and coastal valleys later this morning. Most of the beaches will partially clear during the afternoon.

Sunday’s high temperatures will reach the high 80s in the inland valleys (Paso Robles), while the coastal valleys (San Luis Obispo) will hit the mid-70s. The beaches will range between the low to mid-60s.

Along the coastline, some of the coastal firework displays could be partially obscured by the marine layer. The models are indicating a 400-foot cloud ceiling developing on the evening of the Fourth of July.

The models indicate subtle day-to-day changes through Monday with night and morning marine low clouds, fog and mist. Daytime highs will remain near to slightly below-normal for the beaches and coastal valleys and above-normal for the inland valleys and far inland areas.

East of the Central Coast, monsoonal moisture will continue to produce afternoon thunderstorms along the Sierra Nevada with a slight chance for some isolated development across the Central Valley through the Fourth of July.

Strong to gale-force (25 to 38 mph) northwesterly winds are forecast to develop along the coastline on Tuesday and will continue at this level through Thursday. These winds will produce mostly clear skies along the coastline during the late morning and afternoon.

The southerly facing beaches (Cayucos, Avila Beach and Shell Beach) will reach the high 70s, while the other beaches will range between the mid to high-60s.

Away from the coastline, the coastal valleys will reach the low 80s, while the inland valleys the high 90s.

Another area of strong high pressure is expected to expand westward from the Desert Southwest next weekend and could produce triple-digit temperatures in the North County, mid 80s in the coastal valleys and 70s along the shoreline.

The warming trend could continue into the following week with the potential for inland valleys to reach as much as 15 degrees above normal.

Closer to the coast, continued onshore flow will help moderate temperatures; although, the coastal valleys could reach into the 90s, which is around 5-10 degrees above normal.

Surf report

Sunday’s 3- to 5-foot northwesterly (290-degree, deep-water) swell (with an 8- to 11-second period) will continue at this level through Monday.

Increasing northwesterly winds along the Northern and Central California coastline will generate a 5- to 7-foot northwesterly (310-degree, deep-water) sea and swell (with a 5- to 12-second period) on Tuesday through Thursday.

Sunday’s 1- to 3-foot Southern Hemisphere (200-degree, deep-water) swell (with a 15- to 17-second period) will continue at this level Tuesday.

Seawater temperatures will range between 54- and 57-degrees Friday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

PG&E safety tip

With hot temperatures and dry conditions across California, It is more important than ever to put safety first this Fourth of July. The safest way to enjoy fireworks is to attend a public firework show put on by professionals.

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.