Though water restrictions have loosened and people say they are feeling better about reservoir levels, California is still in a long-term drought. More than 20 percent of the state — mainly in the southern half — is still in exceptional drought, which is the worst drought category on the scale. Over 40 percent is in extreme drought.
Drought-busting hope always lurks as we approach winter, and this year is no different. How much rain will California get? Is it going to be more lucky than last winter?
First, we have to state the obvious. Last year we were talking about El Niño, this year we are talking about La Niña. El Niño helped California with a little more rain last year, but La Niña tends to create a wavier jet stream pattern, which favors the northern states with more precipitation than the southern states. That kind of bisects California into wet northern and dry southern regions.
The tricky part this year is that we’re not expecting a strong La Niña, which means the effects might be harder to pin down. If La Niña isn’t strong, it’s more difficult to figure out how the atmosphere is going to respond to it.
Here’s some brutal honesty: Long-range outlooks are often useless. They don’t have much skill beyond climatology, meaning as good as saying what the average weather is on a specific date. But I do think that they might provide some peace of mind; maybe these outlooks help people feel as if they’ve got some kind of control of the situation. Whatever the cause, readers have been asking us for a California outlook, so here’s what some of the experts have to say.
Our first expert couldn’t agree more with the above statement.
“As far as outlooks go, I have yet to find an outlook that I like,” said Jan Null, founder of Golden Gate Weather Services. “[National Oceanic and Atmospheric Administration], Farmers Almanac — you’ve seen the analysis I’ve done of those. There’s no skill there.”
Null said that it’s easy to go to the “La Niña playbook” for this winter — dry south, wet north — but that wouldn’t take into account all of the other atmospheric phenomenon that are happening right alongside it.
There’s the Pacific Decadal Oscillation (PDO), the North Atlantic Oscillation (NAO), the Arctic Oscillation (AO) and the Madden-Julian Oscillation (MJO) — “there’s this whole alphabet soup of other things, and all of those obviously play into it,” Null said. “And then you throw in a warming climate and the skill just isn’t there.”
That being said, Null keeps a phenomenal record of California weather and climate on his website, so we can see exactly what happened in previous years that looked similar to this one. Null is clear to note, though, that this isn’t a forecast. It’s what actually happened, and is likely to bear minimal resemblance to what happens this winter.
On average, a weak La Niña favors northern and central California for more rain. Or at least more closer-to-average rain. Historically, what Central California ends up seeing is highly dependent on how strong the La Niña is.
The National Weather Service isn’t holding much hope for drought-busting conditions this winter, especially in Southern California:
- Drought will probably persist through the winter in many regions currently experiencing drought, including much of California and the Southwest
- Drought improvement is anticipated in Northern California, the northern Rockies, the northern Plains and parts of the Ohio Valley.
“This forecast does not bode well for drought in the country, as we’ll likely see drought persist in central and southern California and the Southwest and potentially expand in the Southeast,” wrote NOAA long-range forecaster Mike Halpert. “Thus, the likely weak La Niña means California drought relief is not likely.”
Daniel Swain, a postdoc climate scientist at the University of California at Los Angeles who runs the blog Weather West, doesn’t have high hopes for a wet winter. In particular, he notes that the Ridiculously Resilient Ridge is likely to make a comeback. That persistent warm and dry pattern pushed the California drought into extreme territory in the winter of 2014-2015 (emphasis mine):
How concerned should we be about a 2016-2017 return of the Ridiculously Resilient Ridge? Well, the tropical Pacific Ocean has been edging back toward a La Niña-like state, with relatively cool water in the eastern Pacific. Meanwhile, very warm conditions are expected to return to the tropical West Pacific over the next few months — a setup that is linked to unusually strong high pressure over the northeastern Pacific.Extraordinary warmth continues across many areas — especially in the Arctic, where seasonal refreeze of the Arctic Ocean has been occurring at a record-slow rate (leading to record-low ice extent in October). The unfavorable state of the tropical Pacific Ocean, plus the high likelihood of persistent warmth yet again this winter, suggests that we’re still likely to be talking about the “ongoing California drought” well into 2017.
Zack Labe, a PhD student at the University of California at Irvine, agrees with the idea that it’s more likely to be rainy in the north than the south. But he, too, has reservations:
I will be honest; I am not a huge fan of winter outlooks given they can be so easily affected by internal variability and extremes. Last year is a good example of that in California.I think there is a bit more confidence though in the temperature outlook, which is likely to be warmer than normal. I expect drought conditions will continue to be widely persistent across central and southern portions of the state.Most importantly, I think it is critical for people to continue to conserve water and beware of their footprint. Even under a wetter pattern, warming surface temperatures will continue to affect/dwindle our snow pack in the Sierras (this will be a major story going forward).
AccuWeather is splitting the odds between Northern and Southern California. Like NOAA, it’s seeing wet conditions in the north and dry conditions in the south. “I do think in the early part of the season we’re looking good anywhere from San Francisco, Sacramento and into the mountains,” said Paul Pastelok, a forecaster for AccuWeather.
. . . warm and dry conditions will span much of the season for central and Southern California and the Southwest.For Southern California, the pattern will exacerbate ongoing drought conditions.What precipitation does fall in California will aim primarily for the north, though it will fail to have the significance of last January when the region was hammered by heavy rain and snow.