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LinkedInWet December, Dry January: Thoughts about California Rain
With the heavy rains that hit northern California in December, the buzzing about snow in San Diego County, and the more recent rainfall in Los Angeles, I was curious as to how much that precipitation helped dampen California soil as the state enters its fourth year of drought. In summary, although it provided temporary drought relief, the recent precipitation was nothing compared to the 11 trillion gallons of water NASA predicted in December 2014 that is needed to get California out of this long-term drought. On the bright side, it looks as if our conference will be timely and I can continue to avoid the discomfort of closed-toed shoes.
Although the rains didn't even put a dent into the amount needed, they were quite intense! In fact, San Jose set an all-time record for wettest December day in its history and extreme winds hit several parts of the west coast. The prolonged December precipitation was due to the combination of an atmospheric river and a surface low pressure area off the coast of northern California. It'll be interesting to see the changes in the development and movement of atmospheric rivers over the century as climate change continues to occur. Some say they will grow stronger because a warmer climate means more water vapor can be lifted out of the ocean. (NOAA has just launched a cool new campaign, CalWater 2015, dedicated to better understanding atmospheric rivers. Check it out here!).
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Animation of an atmospheric river from December 2014. See http://www.esrl.noaa.gov/psd/atmrivers/ |
Unlike December, January turned out to be incredibly dry and cold. Although it's not unusual for several dry weeks in January, we've gone all month without a drop! Things aren't looking good for the Sierra snowpack (more info on this next week from Laura!). Daniel Swain has an explanation for this mixed bag of California weather events:
A high-amplitude atmospheric flow pattern has once again developed over the Eastern Pacific and North America, deflecting the Pacific storm track north of its typical cool-season position along the West Coast and allowing repeated intrusions of extremely cold Arctic air to invade the American Midwest and Eastern Seaboard.
Sound familiar? As of January 17th, however, there still hasn't been strong enough evidence to say that the Ridiculously Resilient Ridge has returned…stay tuned.
