Downtown Los Angeles had a daytime low of 49 on Memorial Day, the first sub-50 day in the month of May since 1967. Afternoons have been unusually cool as well. Only two days this month have reached 75 degrees or higher in Los Angeles. In the record since 1878, only six years have had fewer.
The chill gripping Southern California lasted into Tuesday’s early hours, with the San Diego suburb of El Cajon reporting a record low of 48 degrees. The persistent cool weather has left towns like Barstow, Ojai, Bakersfield and Fresno experiencing a top-10 coolest May on record to date.
With lots of cool weather comes rain.
The Memorial Day weekend washout was the latest in a trend that began two weeks ago, when three weak but out-of-season atmospheric rivers sloshed into the state. At San Diego’s Lindbergh Field, the gauge has tallied 0.8 inches; the norm for May is about a quarter of that. It’s a similar story in San Francisco, which has seen 2 inches of rain in the month when the average there for May is about a half-inch.
Meanwhile, California’s ski resorts are enjoying — to flip the famous 1966 surfing travelogue on its head — the endless winter. Many have been bragging about staying open through the Fourth of July, but Mammoth Mountain Ski Area is pushing the envelope back a few weeks. They’ll be hitting the slopes until August there.
Over the recent weekend, Mammoth picked up an additional 3 to 6 inches of fresh powder — a nice topping to the snow there this month, which has now set a new May snowfall record. Across the Sierra Nevada range, the snowpack is more than double the late-spring norm.
Of course, every day with rain or snow delays the onset of wildfire season.
But the same abundant precipitation is allowing another round of wildflowers and grasses to grow, which could lead to trouble after (or, if) summer finally arrives. As it was explained, “having multiple large grass crops makes it more likely that last year’s burn scars could carry fire, as a continuous fuel bed exists despite one grass crop thinning and dying due to heat.”
And that heat might arrive in perhaps a week, according to midrange forecasts.
The most recent six-to-10-day outlook by the National Weather Service’s Climate Prediction Center gives almost all of central and northern California a 70 percent chance of above-average temperatures. Already, the Weather Service is predicting daily highs in the northern Sacramento Valley to reach triple digits by Monday, which is some 10 to 15 degrees above normal.
But before then, low pressure aloft will develop over the Pacific Northwest before moving southward Thursday into interior California. Although not as deep or cold as the Memorial Day weekend system, the mid-level cold air will help destabilize the lower atmosphere — resulting in another round of higher probabilities of showers and storms, especially over the mountains.
In other words, there’s still more precipitation to come in this seemingly never-ending storm season.