El Nino took its time, but the National Weather Service announced on Thursday that the long awaited system had finally arrived.
Before allowing any sighs of relief, meteorologists hastened to add that this particular El Nino is very late and extremely weak, barely meriting an upgrade in status from “watch” to “advisory.”
“For us it’s not a factor,” said Eric Kurth with the National Weather Service office in Sacramento.
Early in the summer of 2014, forecasters believed conditions were right for a moderate to strong El Nino system to emerge this winter. And Ken Clark, expert meteorologist with Accuweather.com, points out that a weakened version has indeed been in place for the past few months.
The term El Nino applies to weather patterns that emerge when warming of the sea surface in a certain region of the central Pacific meets with convection in the air over the waters east of that warming patch. But this year the atmospheric component has been slow to evolve.
“You need that combination,” Kurth said. “We haven’t seen convection until recently.”
In the short term, El Nino’s quiet arrival will hardly be a factor. The National Weather Service anticipates a warm and dry spell into next week, with record temperatures over the weekend in some parts of northern California.
Early next week, things become more interesting.
Kurth expects a low pressure system to reach the coast of northern California on Tuesday and move inland with potential for rain. But the forecast models disagree on what happens next. One shows the system weakening, another has it gaining strength and dumping noticeable amounts of rain.
“It may end up being somewhere in the middle,” Kurth said. “If one model is right, there could be snow in the Sierras, but that’s a big if.”
The lack of power in this newly announced El Nino makes predictions difficult. A weak system often passes over California with little effect. Sometimes it even brings drought conditions.
“With a strong El Nino you get wet weather,” Clark observed. “With a weak El Nino it doesn’t correlate as well.”
While the National Oceanic and Atmospheric Administration offered up a near 50-50 chance of the pattern lasting through summer, both Accuweather and the National Weather Service agree that the pattern’s emergence so late in the season will mean minimal impact, either way.
At the moment, 67 percent of the state ranks in extreme or excessive drought, down from 82 percent in October, the beginning of northern California’s rainy season.
But, warns Clark, “it’s still not that good.”
For one, 66 percent of the state met drought conditions on this day a year ago. To make matters worse, according to Clark, the level of water packed into the snow in the Sierras is currently at 19 percent. Last year the mark reached 33 percent.
“We could use the long term water that the Sierras usually provides from melt off,” Clark said.
So El Nino offers little in the way of drought relief. In fact, Kurth cites long term tendencies suggesting above average temperatures lasting through September and perhaps beyond.
If there is a bright spot, the National Weather Service predicts above average precipitation for Lake County in models running through March 14. And because of mid-December’s powerful storms, the county remains above average in seasonal rainfall.
“Lake County is one of the few counties in California that can say that,” Kurth pointed out.
Dave Faries can be reached at 900-2016
