Discussions of the pending El Niño weather pattern have shifted from its probability to which month will it peak and its longevity.
Last week, the latest National Weather Service forecast stated, “El Niño will likely peak during the Northern Hemisphere winter 2015-16.” Neutral conditions are expected by late spring and possibly early summer 2016.
The environmental indicators, such as sea surface temperatures, are well above their normal range. “Collectively, these atmospheric and oceanic anomalies reflect a strong and mature El Niño episode,” was the NWS conclusion.
NWS continues to expect a very wet winter, “[T]his El Niño could rank among the top three strongest episodes … going back to 1950.” A strong El Niño is correlated with above normal precipitation in Southern California. According to a NWS advisory last week, the current conditions are the strongest recorded.
“Above-normal precipitation and frequent storms are expected for Southern California with the best chance from December through March and moderate snow levels (not the tropical high snow events and not the arctic air mass),” is the most current NWS forecast.
The expectation for greater rainfall is being enhanced by the “blob” of warm Pacific water to the west of California. El Niños are created and influenced by equatorial warm waters.
NWS adds, “El Nino can impact the jet stream to bring more frequent storms during the wet season, but not necessarily stronger storms (not just the Pineapple Express or Atmospheric River).”
Even though the foreboding El Niño has not yet arrived yet, in both Idyllwild and Pine Cove rainfall since July 1, the beginning of the rain year, has exceeded the average long-term rain through the end of November.
No additional precipitation is forecast through the end of November. However, U.S. Forest Service meteorologists have said, “… confidence is high that our region will see above-normal rainfall this winter, however, as with the last strong El Niño (1997-98), significant (season-ending) rains did not occur until the early to middle part of December.” And they expect Southern California “… may bear the brunt of the storms.”