El Niño has been a no-show in Southern California this year, despite endless fall warnings of a Godzilla event (including those transmitted by yours truly).
So what happened?
Short version, according to a post put up on the Weather West blog by the wise young Daniel Swain of Stanford, is we don’t know — but we have suspicions.
…I’ll reiterate that it’s impossible to discern in real time–and especially within the confines of a blog post–exactly why California has been considerably drier than expectations during the present very strong El Niño event, and why West Coast ridging [high pressure build-up] has been so prominent during recent winters. One thing that is clear is that warming temperatures have already increased the likelihood and severity of drought in California–irrespective of changes in precipitation patterns.
Swain argues that the “subtropical ridging” is not a return of the dreaded Ridiculously Resilient Ridge that created the California drought of the past five years — at least not yet — and reminds us that the winter is not yet over, and suggests the pattern could shift soon:
…there are still tantalizing signs of a potential shift to much wetter conditions by the very end of the month. The GFS and ECMWF ensembles have both been suggesting that the anomalously deep Gulf of Alaska low which has been present so far this winter will shift subtly eastward over the coming 2 weeks, eventually displacing the West Coast ridge far enough to the east to allow the “storm parade” which has been present across the North Pacific for the entire winter to reach California.
That suggestion is shown in this model animation in the early days of March. (Watch the low move into California as the days in the marker at the top pass by.)
To the Ventura County Star, local hero Bill Patzert, of JPL/NASA fame, argues that the El Niño this year might have been so big it pulled the subtropical jet stream into NorCal, but likewise suggests that could change:
Forecasts that El Niño would bring a conveyor belt of wet storms have yet to materialize in Southern California.
But experts say it’s not too late. There are still two months to go.
Climatologist Bill Patzert, of NASA’s Jet Propulsion Laboratory in Pasadena, said he’s still counseling patience and optimism.
The El Niño didn’t start to peak until January and February. It might have been too big, pushing the subtropical jet stream farther north. As its intensity decreases, that could change.
There is precedent for that, Patzert said. In 1983, “the big show didn’t really happen until March and April.”
Meanwhile, El Niño storms have boosted the Sierra Nevada snowpack, which provides about one-third of California’s water, including in east Ventura County.
True. But the rainfall numbers this year for Ventura County are little short of dismal:
Let us pray.