SLO County heat wave will ease soon. Here’s what ahead in the forecast
Last week, a ridge of high pressure over California produced Santa Lucia (northeasterly) winds and record-breaking temperatures throughout the Central Coast. Many coastal valleys (San Luis Obispo) reached triple-digit levels for the first time in 2024.
This week, we will see increasing northwesterly winds and gradually cooler temperatures.
The ridge of high pressure responsible for the hot weather last week has moved to the east, while a trough of low pressure has taken its place along the California coastline.
This condition will create fresh to strong (19 to 31 mph) northwesterly winds during the afternoon through Tuesday, increasing to strong to gale-force (25 to 38 mph) levels on Wednesday through Thursday. These winds will bring gradually cooler temperatures to all regions.
The afternoon winds should be strong enough to mix out the marine layer, leaving behind primarily sunny skies throughout the Central Coast, with marine clouds with pockets of fog and mist developing overnight and morning in the coastal regions.
The inland valleys (Paso Robles) temperatures will reach the low 100s on Sunday into Monday, while the coastal valleys (San Luis Obispo) will range between the mid- to high 80s. The beaches will warm up to the high 60s, except for Cayucos, Avila Beach and Shell Beach, which will reach the mid-80s.
Temperatures will continue to decrease gradually on Tuesday through Friday, with the inland valleys dropping to the high 80s and the coastal valleys in the mid-70s.
Gentle onshore winds on Friday through the start of the following week will allow a deep and persistent marine layer with areas of fog and mist to develop overnight in the coastal regions, with partial afternoon clearing along the beaches.
The models have been advertising an early-season low-pressure system moving southward along the California coastline between September 19 and 21.
This system has the potential to produce scattered rain showers and cool temperatures, with the North County only reaching the mid-60s.
Weather watches and warnings
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Surf report
A 4- to 6-foot northwesterly (300-degree deep-water) sea and swell (with a 5- to 11-second period) is forecast along our coastline through Tuesday, increasing to 8 to 10 feet (with a 5- to 8-second period) on Wednesday. This northwesterly sea and swell will lower to 5 to 7 feet with the same period on Thursday.
A 2- to 4-foot northwesterly (290-degree deep-water) swell (with an 8- to 11-second period) is forecast along our coastline on Friday through next Sunday.
Surface seawater temperatures will range between 55 and 58 degrees through Tuesday. Seawater temperatures will cool to 52 to 54 degrees on Wednesday through Thursday due to increasing amounts of upwelling.
On this date in weather history (Sept. 8):
1900: The greatest weather disaster in U.S. history occurred when a hurricane struck Galveston, Texas. A tide 15 feet high washed over the island demolishing or carrying away buildings and drowning more than 6,000 people. The hurricane destroyed more than 3,600 homes. Winds up to 120 mph, and a 20-foot storm surge accompanied the hurricane. Following the storm, the surf was 300 feet inland from the former water line. The hurricane claimed another 1,200 lives outside of the Galveston area. — David Ludlum
2017: The Paso Robles Airport dropped below 60 degrees this morning, the first time since May 18 when the temperature reached 57 degrees. Along the beaches and coastal valleys, the marine layer with areas of fog and mist has kept the morning temperatures in the 60s.
This week’s temperatures
LOWS AND HIGHS, PASO ROBLES
SUN | MON | TUE | WED | THU | FRI | SAT | SUN |
58, 102 | 57, 100 | 56, 93 | 55, 90 | 53, 88 | 54, 89 | 55, 87 | 55, 88 |
LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS
SUN | MON | TUE | WED | THU | FRI | SAT | SUN |
59, 89 | 58, 86 | 58, 78 | 57, 78 | 56, 78 | 56, 76 | 57, 75 | 59, 76 |
John Lindsey is a retired PG&E marine meteorologist. Email him at JohnLindseyLosOsos@gmail.com or follow him on Twitter @PGE_John.
