SLO County weather for week of July 31: Expect ‘monsoon moisture’ with chance of thunderstorms

A late July to early August weather pattern with monsoon moisture will transition to a spring type of weather pattern with strong to gale-force (25 to 38 mph) northwesterly winds on Wednesday into Friday.

Abundant monsoon moisture will continue to stream over the Central Coast with variable amounts of mid- to high-level clouds, and a chance of widely scattered rain showers throughout the Central Coast on Sunday night into Tuesday morning.

There will also be a chance of thunderstorms in the elevated terrain of the eastern regions of San Luis Obispo and Santa Barbara counties on Sunday afternoon into Tuesday.

The subtropical moisture will also help to dissipate the marine layer during the late morning and afternoon hours.

This weekend’s high temperatures will range from the 60s at the beaches and mid-70s in the coastal valleys. The inland valleys will reach the low to mid-90s. These temperatures will continue through the end of the week, with no extreme heat anticipated through the following week.

The afternoon northwesterly winds will increase the strong (25 to 38 mph) levels on Wednesday into Friday, bringing slightly cooler temperatures to the coastal regions.

Another slug of subtropical moisture is expected to move through the Central Coast during the second week of August.

Surf report

Sunday’s 2- to 4-foot northwesterly (290-degree, deep-water) swell (with an 8- to 11-second period) will remain at this level through Tuesday.

Strong to gale-force (25 to 38 mph) afternoon northwesterly winds will generate a 5- to 7-foot northwesterly (300-degree, deep-water) sea and swell (with a 5- to 8-second period) on Wednesday through Friday.

A 1- to 2-foot Southern Hemisphere (200-degree, deep-water) swell (with a 15- to 17-second period) will arrive on Sunday and will remain at this level through Friday.

A rare occurrence along the Central Coast, Hurricane Frank off Baja California should track far enough northwestward to produce a 2- to 4-foot southerly (175-degree, deep-water) swell (with a 12- to 14-second period) on Monday through Wednesday.

Seawater temperatures will range between 55 to 58 degrees through Friday.

This day in weather history: July 31

1986 - The temperature at Little Rock, Arkansas, soars to 112 degrees to establish an all-time record high for that location. Morrilton, Arkansas, hits 115 degrees, and daily highs for the month at that location average 102 degrees.

2015 - The month’s second full moon is the first such occurrence in the Americas since August 2012. Every month has a full moon, but because the lunar cycle and the calendar year aren’t perfectly synced, about every three years we wind up with two in the same calendar month.

2017 - Paso Robles hits 106 degrees, while closer to the coast, San Luis Obispo reaches 79.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

John Lindsey is a retired PG&E marine meteorologist. Email him at JohnLindseyLosOsos@gmail.com or follow him on Twitter @PGE_John.