Dry weather to last through Christmas Eve

Winter will begin on Dec. 21st, but it won’t feel like it.

San Diego is locked in a long-term weather pattern that will keep the region dry and reasonably warm through Christmas Eve, says the National Weather Service.

“It’s possible that we won’t get any significant rain at all during the entire month of December,” said Brett Albright, a weather service forecaster. “There’s a ridge of high pressure that’s preventing storms from coming our way.

“We might get more Santa Ana winds before the pattern changes. Those winds kick up warm air, keeping it warmer in the canyons and foothills at night.”

San Diego International Airport averages 1.57’’ of precipitation in December, and 3.11’’ from October 1st to December 31st. That three-month period is close to ending, and the airport has received only 0.2” of rain. The only time it was drier during those three months was in 1929, when the region recorded only a trace amount of precipitation.

Periodically, weather patterns change quickly, undermining forecasts. So it’s possible that San Diego could get significant rain toward the end of the month. But it doesn’t seem likely.

The current conditions are worrisome to forecasters and firefighters.

San Diego County received above average rainfall last year, and it spawned the growth of vegetation, including some of the most lush flower blooms seen locally over the past decade.

But it’s been generally dry since then, with several notable heatwaves that have dried out the low grasses, making wildfires more likely.

The situation could get worse. Federal forecasters say that a La Nina is developing in the Pacific. The periodic change in climate typically produces below average rainfall in Southern California during the winter. But not always.

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