Weather Watch

Plenty of chilly rain but no snow from latest storm

A cold early season low-pressure system raced through San Luis Obispo County on Saturday morning with much needed rain but no snow.

Despite the cold temperatures Friday morning — both Creston Elementary School and Windrose Farm reached a low of 11 degrees and Daniel Sinton reported a low of 7 degrees at Shell Creek Rd near Shandon — unusually strong southwesterly winds brought in warmer air from the Pacific Ocean Friday night into early Saturday morning before the frontal passage.

This condition kept temperatures above the freezing level in most locations and prevented snow from falling except on the highest peaks.

Usually, the winds along the Central Coast are either out of the northwest, southeast or northeast. I can count on my hand the number times there has been a southwesterly wind event like this. It’s pretty rare.

With Christmas just around the corner, people in our beautiful county often ask if it has ever snowed in San Luis Obispo. Well the answer seems to be yes and no.

Data from Cal Poly, which houses weather and climate records for San Luis Obispo since 1870, indicate no measurable snowfall has ever been recorded in town. Snowfall is measurable when there is at least one-tenth of an inch on the ground. San Luis Obispo — with its low elevation and mild temperatures because of the strong marine influence from the Pacific Ocean — just doesn’t make a likely candidate for measurable snow.

Over the years there have been reports of snow flurries in town along with some bone-chilling temperatures, but nothing that could be considered measurable snow.

For example, on Dec. 15, 1988, an intense storm from the eastern part of the Gulf of Alaska produced record amounts of snow in the North County (5 to 8 inches) and Santa Margarita (7 inches). That day, San Luis Obispo reported 1.25 inches of rain, sleet and snow flurries with a low temperature of 35 degrees.

A few years later during December 1990, a strong southerly flowing jet stream from Alaska stretching southward to California moved a very cold Arctic air mass from the western Canada “Yukon express” down the West Coast.

There were reports of snowflakes in San Luis Obispo, and even Pismo Beach and Nipomo, on the night of Dec. 20, 1990, with overnight lows falling to the low 20s on the north side of the Cuesta Grade. The next day, the meteorological tower at Diablo Canyon Power Plant reported sustained winds of 35 mph out of the north with gusts reaching 45 mph.

The temperatures dropped to the mid-30s right along the coastline. By Dec. 22, the winds at Diablo Canyon shifted out of the north-northeast with the temperature hitting the freezing point for the first time since Diablo Canyon started recording temperatures in 1976.

Gary Ryan, who was a meteorologist with the National Weather Service in Santa Maria, confirmed record-breaking low temperatures Dec. 22 and Dec. 23, 1990 throughout San Luis Obispo County. Atascadero reached a bone-chilling 4 degrees while Templeton reached a numbing 9 degrees. San Luis Obispo reached 17 degrees. Even the coastline was cold, with Morro Bay reaching 25 degrees and Pismo Beach coming in at 29 degrees.

While the snowfall wreaked havoc on the community, the low temperature kept plumbers busy for days afterward repairing burst pipes and fixtures. In fact, many local hardware stores sold out of plastic and copper pipe and anything else to do with plumbing.

While no official snowfall has been recorded in San Luis Obispo, that doesn’t necessarily mean it did not happen. I once saw an old photograph that showed about an inch of snow on the unpaved streets in San Luis Obispo sometime in the 1800s.

Anyone with memories of a snowfall should drop me a line. I received this email from a reader a few years ago named Ted about the December 1988 snow event: “It snowed on this morning — from Big Sur to Malibu — my son was born in Sierra Vista at 10:03 a.m. and I remember as labor was ending, the doctor commented on the rain and then … snow!! … and then Jesse was born !”

Here are Saturday’s rainfall totals:

Adelaida: 0.95”

Arroyo Grande: 0.28”

Atascadero: 0.52”

Avila Valley: 0.31”

Baywood Park: 0.09”

Cal Poly: 0.23”

Cambria: 0.24”

Camp San Luis: 0.20”

Cayucos: 0.55”

Condor Lookout: 0.40”

Creston at Elementary School: 0.24”

Creston at Humbug Vineyards: 0.19”

Diablo Canyon: 0.24”

Islay Hill: 0.29”

Los Osos: 0.15”

Mission Prep: 0.23”

Morro Bay: 0.12”

Nipomo: 0.37”

Oceano: 0.20”

Paso Robles Municipal Airport: 0.17”

Hwy. 41 West and Toro Creek: 0.80”

Pismo Beach: 0.21”

Point San Luis Lighthouse: 0.26”

Rocky Butte Precipitation: 0.75”

Santa Margarita Fire Dept.: 0.38”

San Luis Obispo Prefumo Canyon: 0.46”

San Simeon: 0.12” 0.29”

See Canyon: 0.44”

Shell Creek Road near Shandon: 0.20”

Templeton: 0.24”