Weather Watch

Think it’s cold in SLO now? In 1990, the ‘Yukon Express’ brought single-digit temps

Early-morning frost decorates Atascadero and Santa Margarita

As temperatures dropped below freezing, parts of San Luis Obispo County awoke to chilly conditions on Feb. 7, 2019, with ice on the roads and frost covering ground, as seen here in Santa Margarita and Atascadero.
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As temperatures dropped below freezing, parts of San Luis Obispo County awoke to chilly conditions on Feb. 7, 2019, with ice on the roads and frost covering ground, as seen here in Santa Margarita and Atascadero.

Frigid air associated with a cold upper-level trough produced a few snow flurries throughout the Central Coast, including San Luis Obispo and Paso Robles last Tuesday and Wednesday morning. However, because of the relatively warm ground temperatures, the snow immediately melted on contact.

Snowfall is measurable when there is at least one-tenth of an inch on the ground.

Nevertheless, farther inland was cooler due to less marine influence, and the snow stuck to the ground along the higher ridges and peaks and was measurable.

There will be a greater chance of snow sticking to the ground over a greater area Sunday morning, and here’s why.

A deep (523 decameters) upper-level low-pressure system centered over Eastern Oregon will draw in frigid air from the Yukon and push it southward along the California coastline toward the Central Coast. Near the Earth’s surface, a cold front will move southeastward through San Luis Obispo and northern Santa Barbara counties on Sunday morning with rain and low-level snow.

Snow levels are expected to fall to 2,000 feet along the coastline and 1,500 feet farther inland.

The models are indicating between a half and three-quarters of an inch of rain is expected at the lower elevations on Sunday morning. If the models verify, this should produce between 3 and 6 inches of snow accumulation on the higher ridges and peaks of Central California.

Some of the highways and roads that are most likely to be impacted by the predicted snowfall are Highway 58, east of the California Valley to McKittrick with a summit of 3,528 feet. Highway 166 to the Reyes Station summit to Maricopa at 2,968 feet and State Route 154 at the San Marcus pass with an elevation of 2,225 feet. Snow may also be likely in Cuyama with a height of 2,262 feet and the California Valley at 1,970 feet. There is a slight chance of snow on Highway 101 over the Cuesta Grade at 1,522 feet but a greater likelihood on Highway 46 on the Antelope Grade at 1,765 feet.

The recent bout of frosty mornings has led to a series of questions from readers asking about snow and the most frigid temperatures seen in our region.

In December 1990, a heavy, southerly flowing jet stream moved a cold Arctic air mass from western Canada, the so-called Yukon Express, down the West Coast. There were reports of snowflakes in Paso Robles, San Luis Obispo and even Pismo Beach and Santa Maria on the night of Dec. 20, 1990, with overnight lows falling to the low 20s on the north side of the Cuesta Grade.

On that day in the Bay Area, a bitterly cold and cutting north wind blew across the Marin Headlands on the north side of the Golden Gate Bridge toward San Francisco. The sky was overcast, which gave an ash-gray hue to the surrounding mountains; you didn’t see anybody on that international orange span.

Farther south, the meteorological tower at Diablo Canyon was reporting sustained winds of 35 mph out of the north, flowing toward the south with gusts reaching 45 mph. The temperatures dropped to the mid-30s right along the shoreline. According to the National Weather Service (NWS) Wind Chill Chart, it felt more like the high teens. Very cold, indeed!

By Dec. 22, 1990, the winds at Diablo Canyon shifted out of the north-northeast, and the temperature hit the freezing point for the first time since 1976 when Diablo Canyon first started keeping weather records. It was cold throughout the Western United States — Denver reported 20 degrees below zero, while Wild Reservoir north of Elko, Nevada, plunged to 31 degrees below.

Gary Ryan, who was a meteorologist with the NWS in Santa Maria, confirmed record-breaking low temperatures on Dec. 22 and Dec. 23. Atascadero reached a bone-chilling 4 degrees while Templeton reached a numbing 9 degrees. The Paso Robles Airport reported an all-time low of 8 degrees.

San Luis Obispo dropped to 17 degrees. Even the temperatures along our coastline were freezing, with Morro Bay reaching 25 degrees and Pismo Beach coming in at 29 degrees. Santa Maria recorded a low temperature of 21 degrees, while Lompoc dropped to 20 degrees. Lake Cachuma saw temperatures as low as 16 degrees.

Freezing winds blew through the Salinas Valley and killed or severely damaged many eucalyptus trees along the Highway 101. The region’s avocado crop was hard hit and many water pipe bursts. Plumbers were kept busy for days afterward repairing pipes and fixtures.

Many local hardware stores were completely sold out of plastic and copper pipe and anything else to do with plumbing.

Turning pancakes into water!

Bring your family, friends, coworkers or just yourself! Whatever you do, don’t delay; buy your tickets today! It’s a beautiful way to start Valentine’s Day.

Mike Cannon and I will be flipping pancakes starting at 7 a.m. Thursday at 1050 Southwood Drive in San Luis Obispo. Kids under 10 eat free with each paid adult. Proceeds will fund clean water projects in developing countries. To purchase a ticket contact Liz Moody at 805-544-7407 or email LizM@CannonCorp.us.

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