Weather Watch

Getting sick of the rain, SLO? Well, get used to it, we’re ‘locked in’ to this pattern

I’m starting to receive complaints about the number of rainy days San Luis Obispo County has had recently, and I’m sure the frequency of grumbles will increase as the long-range models and charts continue to indicate that the wet weather pattern will continue into the end of February.

The atmosphere may continue to produce above-average rainfall well into March, as it seems to be locked in to this track.

Except for this upcoming Monday, Tuesday and Wednesday, which will be dry, there is a chance of rain every day through early March as a trough of low pressure remains along the West Coast and the Eastern Pacific High is parked nearly 1,500 miles to the west-northwest of California.

Last year at this time, the ‘ridiculously resilient’ ridge of high pressure was parked over California. Not only was it dry, but also warm. Temperatures averaged 10 degrees warmer than typical at the Santa Maria Public Airport, 15 degrees hotter at the Paso Robles Municipal Airport and nearly 20 degrees above historical levels at the San Luis Obispo County Regional Airport.

The combination of lack of rainfall and well above-normal temperatures drove most of San Luis Obispo County into a D1 (Moderate Drought) condition and Santa Barbara, Ventura and Los Angeles counties into D2 (Severe Drought), according to the United States Drought Monitor. At that time, “The presence of a mild La Niña, the notorious ‘Diva of Drought’ was present at the equator, which didn’t bode well for winter rainfall,” said climatologist Bill Patzert, of NASA’s Jet Propulsion Laboratory.

If it wasn’t for the mini-Miracle March of 2018, the Central Coast might have finished the rain season at less than 25 percent of normal.

So far this rain season, which runs from July 1, 2018, through June 30, 2019, gauges throughout the Central Coast have recorded roughly 134 percent of average rainfall for mid-February.

Typically, by this time, both the Paso Robles and Santa Maria airports would have recorded over 8 inches of precipitation. However, this season, the weather station at the Paso Robles Municipal Airport has recorded 11 inches or about 138 percent of normal. The Santa Maria Public Airport has seen 10.5 inches or 123 percent of average for this time of the year. Cal Poly (official home of climatology for San Luis Obispo) has measured 18 inches of rain or 141 percent of typical, while SLOWeather.com in western San Luis Obispo reported 138 percent of average rainfall.

No wonder Nacimiento Lake went from 17 percent of capacity as of mid-January to 61 percent of capacity as of Friday, while Lake San Antonio is at 27 percent. Large watersheds feed both lakes, but Nacimiento Lake, as a rule, will fill up about three times faster than Lake San Antonio due to the larger size and proximity of its watershed to the Pacific.

According to data from SLOCountyWater.org, here are the other San Luis Obispo and Santa Barbara counties lake and reservoir capacity percentages: Lopez Lake is now at 47 percent; Salinas Reservoir near Santa Margarita is at 105 percent and spelling into the Salinas River; Whale Rock Reservoir near Cayucos is over 79 percent; Gibraltar Reservoir in Santa Barbara County is filled and its water is spilling into Santa Ynez River, feeding into Lake Cachuma, which is at 57 percent of capacity.

If all this rain has got you down, remember it could be much worse.

The village of Mawsynram in the state of Meghalaya, India, is perhaps the rainiest spot on Earth; on average it receives 467 inches of rain per year! Not far behind is Mt. Waialeale on Kauai in Hawaii, which gets about 460 inches of rain each year. In the lower 48, Aberdeen Reservoir in Washington has a yearly precipitation averages of 131 inches.

In California, Gasquet near the Oregon border in Del Norte County reports average precipitation of nearly 72 inches per year, while the tiny and former logging town of Cazadero in Sonoma County north of the Russian River typically gets 75 inches of rain per year.

Locally, Rocky Butte receives 40 inches per year in the Santa Lucia Mountains of San Luis Obispo County, while south in Santa Barbara County, Santa Barbara TV Peak on top of the Santa Ynez Mountains gets nearly 30 inches per year. However, the most considerable amount of yearly rain along the Central Coast is at Doc Miller’s Place.

He has been keeping track of the rain for 38 years at his property on Pine Mountain at 2,650 feet of elevation in San Luis Obispo County. He has estimated that multiplying Rocky Butte rain gauge data by 1.5 times comes close to his total of roughly 60 inches per year.

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