SLO County weather forecast: Expect unseasonably warm temperatures inland and overcast beaches

Typically in October an area of high pressure develops over the Great Basin and produces Santa Lucia (northeasterly) winds. These offshore winds usually create clear skies and the warmest temperatures of the year along the shoreline of the Central Coast. So far this month, a trough of low pressure along the California coastline has created persistent northwesterly (onshore) winds and, in turn, a stubborn marine layer with night and morning fog and drizzle in the coastal regions. A few beaches have remained overcast throughout the day with below-average temperatures.

Away from the ocean, temperatures have been warmer than average. The Paso Robles County Airport usually sees an average temperature of 62 degrees in October, this month, the airport has reported a 70-degree average. Closer to the coastline, the San Luis Obispo County Airport has reported an average temperature of 64 degrees which is typical for this month. The average temperature in Los Osos during October is 65 degrees, but my weather station in Baywood Park has been averaging 58 degrees this month.

Much like last week, moderate to fresh (13 to 24 mph) afternoon northwesterly winds, decreasing during the night and morning, will continue through this work week. Consequently, a persistent marine layer with overnight fog and drizzle clearing during the afternoon will continue throughout the Central Coast. A few of the beaches may remain overcast throughout the day. An exception to this weather pattern could develop on Tuesday morning as a transitory area of high pressure moves eastward over the Great Basin producing Santa Lucia winds, sunny skies, and warmer temperatures along the beaches.

High temperatures on Sunday will range from the high-50s to the low-60s at the beaches, the high-60s in the coastal valleys (San Luis Obispo), and the mid-70s in the inland valleys (Paso Robles). Warmer temperatures are forecast on Tuesday into Friday, with the inland valleys reaching the high-80s and the coastal valleys the high-70s.

At this time, this weather pattern is expected to continue through next week as there are still no signs of the Santa Lucia (northeasterly/offshore) winds. However, an unsettled weather pattern could develop the following week (October 26, 27, and 28) as a series of cold fronts move southward through California.

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 into Monday, becoming a 4- to 6-foot west-northwesterly (285-degree, deep-water) swell (with an 8- to 15-second period) on Tuesday through Friday.

A 1- to 2-foot Southern Hemisphere (230-degree, deep-water) swell (with a 14- to 16-second period) is expected along our coastline on Sunday through Wednesday.

Seawater temperatures will range between 57 and 61 degrees through Friday.

This Date in Weather History (October 16):

1913 - The temperature in Downtown San Francisco soared to 101 degrees to equal their record for October.

1989 - Heavy snow blanketed the foothills of Colorado. Up to three inches were reported around Denver. Echo Lake was buried under nineteen inches of snow. Temperatures again warmed into the 80s and lower 90s in the eastern and south central U.S. Thirteen cities reported record high temperatures for the date, including Atlantic City NJ with a reading of 84 degrees. (Storm Data)

2014 - Seawater temperatures ranged from 62 and 66 degrees along the Pecho Coast.

2015 - Overnight minimum temperatures once again broke records.San Luis Obispo cooled to 64 degrees last night. The previous record was 56 degrees recorded in 1934.

2020 - The Santa Lucia (northeasterly) winds are weaker this morning;

consequently, temperatures are cooler along the beaches and in the coastal valleys than yesterday. An 84-degree reading on top of date Davis Peak indicates the genesis of an inversion layer, which suggests the development of coastal stratus.

Variable amounts of smoke will continue to stream westward over the Central Coast from the Creek Fire and Bullfrog Fire northeast of Shaver Lake in Fresno County through Saturday.

This week’s temperatures

LOWS AND HIGHS, PASO ROBLES

LOWS AND HIGHS, SAN LUIS OBISPO AND COASTAL VALLEYS

John Lindsey is a longtime meteorologist who lives in Los Osos. Email him at JohnLindseyLosOsos@gmail.com.