This winter has been unusually warm and dry for all of California. In fact, 2013 was the driest calendar year on record. And the forecast shows no rain in sight.
So what’s the problem? It turns out that an unusually resilient high pressure zone is parked over the northeastern Pacific Ocean. The existence of this pressure zone is not unusual – high pressure zones are responsible for the glorious 2-3 weeks respite from the rain that we usually receive in January or February. They essentially serve as virtual mountain ranges that block or deflect storms coming in off the ocean.
However, high pressure zones usually come and go, whereas this one has stayed in the same location since December 2012. Scientists continue to be baffled by the extraordinary resilience and geopotential height of this mass of high pressure (nearly 4 miles high and 2,000 miles long), leading one researcher to dub it the “Ridiculously Resilient Ridge.”
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