Hopes Fade For Strong El Niño Year
El Niño conditions, the much hyped and hoped-for salvation that might end or at least dampen California’s drought, could turn out to be as fickle as most Golden State storm events have proven to be over the past three years.
U.S. Climate Prediction Center’s (CPC) current report on Pacific Ocean weather patterns suggests climate experts are backing off earlier predictions of a strong El Niño shaping up in the equatorial Pacific. They had previously raised a fairly good possibility of a much-needed wet winter.
The most recent outlook says an El Niño is likely to form. It’s just that there might not be much of it.
That’s bad news for California, all of which is being impacted by terrible drought conditions. El Niño conditions about one-third of the time are associated with winter weather patterns that result in above-average precipitation across much of California.
A weaker El Niño is apt to bring some additional precipitation to Southern California, as is now being reflected in long-range climate forecasts.
STRONG EVENT NOT SEEN
A statement from the CPC says, “Over the last month, no significant change was evident in the model forecasts … with the majority of models indicating El Niño onset within June-August and continuing into early 2015. The chance of a strong El Niño is not favored…. At this time, the forecasters anticipate El Niño will peak at weak-to-moderate strength during the late fall and early winter.”
They list chances of any intensity of El Niño as being about 70% during the Northern Hemisphere summer and close to 80% during the fall and early winter.
The San Francisco Chronicle reported the projected El Niño strength has been reduced because ocean temperatures near the International Date Line have not continued to rise since earlier this year when temperatures there were well above average.
“El Niño would be the one way that we could … really breathe a sigh of relief and say, ‘OK, good. This winter should alleviate this drought’,” said Mike Dettinger, a research hydrologist with the U.S. Geological Survey.
HIGH PRESSURE SYSTEMS
Another factor, at this point unpredictable, is the semi-permanent Pacific high pressure ridge
It typically digs in to block all storms during the summer and early fall. In a normal winter, the Pacific high decreases in intensity and moves further south, permitting storms to move across California with rain and snow.
That has rarely occurred during the past three winters. Instead, the Pacific high pressure has tended to stay put for extended periods, acting much more “permanent” than it should and bouncing storms into the Northwest and British Columbia.
DROUGHT TO CONTINUE
Meanwhile, the CPC sees drought conditions persisting or intensifying over all portions of California through October, the month that the 2014-15 water year begins.
The long-range San Joaquin Valley precipitation outlook is more vague, calling for “equal chances” or above or below average precipitation from late summer into early spring, with above average precipitation in Southern California.