More muggy, hot weather could be on way for SLO County. See forecast

A typical July weather pattern will continue through Monday with seasonal temperatures. Then, extensive subtropical moisture will spread over the Central Coast on Monday night into Wednesday morning, bringing warm, muggy conditions, followed by robust northwesterly winds along the coast and triple-digit temperatures in the inland valleys for the rest of the week.

A trough of low pressure along the California coastline will produce gentle to moderate (8 to 18 mph) northwesterly winds through Monday, which will allow the marine layer to develop along the beaches and surge into the coastal valleys during the night and morning with pockets of fog and mist.

Temperatures will range between the low to mid-90s in the inland valleys, including in Paso Robles and at the Mid-State Fair, while the coastal valleys, such as San Luis Obispo, will reach the mid-to-high 70s. Most beaches will remain in the mid-to-high 60s.

A major change in the weather pattern will impact our area Monday night into Wednesday morning. Hurricane Elida, churning west of Baja California, will move northwestward, weakening to a tropical storm as it moves into the colder water off the coast of Southern California. As it continues to move northwestward, it will weaken to a tropical depression about 720 miles west of Point Conception by Tuesday night.

Since the storm is so far out to sea, rainfall is not anticipated on the Central Coast. However, it will produce gentle-to-moderate (8 to 18 mph) southerly winds, extensive mid-to-high level clouds, and muggy and warm conditions, especially along the beaches. In fact, overnight and morning lows will remain in the mid to high 60s.

This tropical cyclone will need to be monitored closely. If it takes a northerly track, it could produce gale-force southerly winds, moderate to heavy rain, and thunderstorms throughout Southern and Central California.

This system will be followed by fresh-to-strong (19 to 31 mph) afternoon northwesterly winds and clearing skies away from the ocean, where night and morning low marine stratus clouds will redevelop later Wednesday through the rest of the week.

Temperatures will reach triple-digit levels starting on Wednesday and will continue to hit the low 100s in the inland valleys through next Sunday, while the coastal valleys, such as San Luis Obispo, will reach the low 80s.

Most beaches will remain in the mid-60s, except the southerly facing beaches of Cayucos, Avila Beach and Shell Beach, which will reach the high 70s.

Surf report

A 3- to 5-foot northwesterly (295-degree, deep water) swell (with an 8- to 16-second period) is forecast along the Central Coast through Wednesday morning.

Combined with this northwesterly swell, there will be a 3- to 4-foot (210-degree, deep water) swell (with a 12- to 14-second period) from Tropical Cyclone Elida on Monday into Wednesday.

Increasing northwesterly winds along the Central California coastline will generate a 5-to 7-foot northwesterly (300-degree, deep water) sea and swell (with a 5- to 9-second period) on Wednesday afternoon through Thursday.

This northwesterly sea and swell will lower to 4 to 6 feet (with a 7- to 9-second period) on Friday through next Sunday.

Once again, the Southern Hemisphere is coming alive with intense storms.

A 1- to 2-foot Southern Hemisphere (225-degree, deep water) swell (with a 20- to 22-second period) is forecast to arrive along our coastline next Saturday, building to 2 to 3 feet (with an 18- to 20-second period) next Sunday and Monday. This swell will peak next Tuesday and Wednesday at 3 to 5 feet (with a 16- to 18-second period).

These wave heights will be much higher along many of the beaches of Southern California.

Seawater temperatures along the immediate coastline will range from 54 and 56 degrees through Monday, warming to 58 and 60 degrees on Tuesday and Wednesday.

Increasing northwesterly winds will drive coastal upwelling and colder, nutrient-rich water to the ocean surface on Thursday through next Sunday.

Consequently, seawater temperatures will cool to 54 and 56 degrees over this time frame.

On this date in weather history

1960: Cow Creek and Greenland Ranch in Death Valley reported morning lows of 102 degrees. The afternoon high at Greenland Ranch was 124 degrees, and the high at Cow Creek that afternoon was 126 degrees. The coolest low for the entire month for both locations was 82 degrees.

2005: During a severe heat wave, Las Vegas, Nevada, tied their record high temperature of 117 degrees, equaling the old record set on July 24, 1942.

2015: Abundant subtropical moisture from the remnants of Hurricane Dolores produced record amounts of July rainfall in San Luis Obispo County. Previous records for the month of July were set in 1950 at 0.59 of an inch in Paso Robles and 0.46 of an inch in San Luis Obispo. A weather station in Paso Robles reported 3.55 inches of rain, while numerous weather stations around San Luis Obispo reported about an inch of rain. Accompanying the rain were about 35,000 lightning strikes, according to www.SLOweather.com

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

SUNDAY: 58, 93

MONDAY: 57, 91

TUESDAY: 65, 94

WEDNESDAY: 66, 100

THURSDAY: 61, 102

FRIDAY: 63, 101

SATURDAY: 62, 101

SUNDAY: 61, 100

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

SUNDAY: 57, 78

MONDAY: 57, 78

TUESDAY: 68, 79

WEDNESDAY: 67, 84

THURSDAY: 60, 83

FRIDAY: 61, 83

SATURDAY: 61, 82

SUNDAY: 62, 80

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