Saturday, October 17, 2015

A "too big to fail" El Nino storm is coming to us this Winter

Strongest impacts expected in January and February, 2016. 

San Jose Mercury News/Science and Environment/Paul Rogers, 10/8/15.  "El Nino" when will it start raining in California?"

National Oceanic and Atmospheric Administration report released Thursday predicts a greater than 95 percent chance that El Niño will last through the winter and into the spring and pack above average rain and temperatures.Following are 10 signs that El Niño may be coming: Photo: NOAA
Above average rain expected, January, February,
(and maybe March, as was the case in 1983).
Red = warm; orange = dry; green = wet.
 .... "An analysis of the five winters back to 1950 in which strong El Niño conditions similar to this year have occurred shows that in the Bay Area during those years, October has been only slightly wetter than the historic average. November has been nearly twice as wet in most. December has been oddly drier than normal in all five strong El Niño winters. And the bulk of the rain -- the real downpours with high risk of floods and mudslides -- have occurred in January and February.  "For the most part, our rainy season really gets going in November, and El Niño is an add-on to our regular rainy season," said Jan Null, a meteorologist formerly with the National Weather Service who runs Golden Gate Weather Services in Saratoga.

Map of waters in the equatorial Pacific Ocean, revealing an El Nino is on its way.
El Nino conditions:
left 10/5/1997; right 10/4/1915.
Using San Francisco rainfall as a baseline for the Bay Area, in four of the five strong El Niño years -- 1957-58, 1972-73, 1982-83 and 1997-98 -- the overall annual rainfall totals have exceeded the historical average of 23.9 inches. In the wettest, 1997-98, the rainfall was double the average, at 47.22, with relentless rainfall in January and February that soaked the state and caused flooding and mudslides. Other Bay Area cities showed similar patterns. "If we don't see a lot of rain in December, we should realize that's not a big deal; it's happened before in strong El Niño years," said Null, who compiled the data. 'January and February have been big months.'" 

.... El Niño is a disruption in the weather patterns over the Pacific Ocean, when the ocean's surface warms more than normal. Those warm waters release heat, changing wind directions and the jet stream, which often brings more and wetter storms to California. Halpert agreed that this year, if big storms come, they aren't likely to come any earlier than in a normal winter."  Read more.

Related article San Francisco Chronicle/SF Gate/Kurtis Alexander, 10/8/15."This year's El Nino still looks like a whopper." Federal forecasters on Thursday reinforced expectations of a strong El Niño this winter, saying there’s a 95 percent chance the burly weather phenomenon, often linked to rain in California, sticks around until spring. Equatorial waters in the Pacific remain extraordinarily warm and trade winds that typically push balmy seas away from the Americas remain weak. The conditions portend an El Niño on par with the giants in 1997-98 and 1982-83, according to the U.S. Climate Prediction Center. In the past, strong El Niños have correlated with above-average rain in the southern United States, with Southern California often a landing pad for major storms and floods. Northern California has historically been less affected by El Niño, though the stronger the system, the higher the chances of rain."

Reference. Comparison with 1997.  Live Science/Jeanna Bryner, Managing Editor, 10/14/15, "Upcoming El Nino may be as wild as 1997 event." "Whether El Niño gets slightly stronger or a little weaker is not statistically significant now. 'This baby is too big to fail', Bill Patzert, a climatologist at NASA's Jet Propulsion Laboratory in Pasadena, California, told NASA's Earth Observatory."

Reference, El Nino description.  State of CA Wildlife/Conservation/Marine/El Nino, "What is El Nino?" "El Niño is a naturally occurring event in the equatorial region which causes temporary changes in the world climate. Originally, El Niño was the name used for warmer than normal sea surface temperatures in the Pacific Ocean off the coast of South America. Now, El Niño has come to refer to a whole complex of Pacific Ocean sea-surface temperature changes and global weather events. The ocean warming off South America is just one of these events."   University Corporation for Atmospheric Research, see "What is El Niño, and what is La Nina?" "El Niño is a warming of the central to eastern tropical Pacific that occurs every two to seven years, on average. The term also commonly refers to the atmospheric rearrangements that occur with the oceanic warming. During an El Niño event, sea surface temperatures across a watery expanse often as large as the United States can warm by 1–3°F or more for a period of from a few months to a year or two.  ....  La Niña, the counterpart to El Niño, is a cooling of the waters across the same region. As with El Niño, the term La Niña typically is used to refer to the associated atmospheric as well as oceanic patterns. It often lasts longer than El Niño, sometimes persisting or recurring for two or more years."

Note photo/graphic.  Image #1 of 58 from the related San Francisco Chronicle/SF Gate article, from NOAA  "National Oceanic and Atmospheric Administration report released Thursday predicts a greater than 95 percent chance that El Niño will last through the winter and into the spring and pack above average rain..."  1997-1915 comparison is from the referenced Live Science article abpve (from NASA Earth Observatory).

Posted by Kathy Meeh

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