The Fading El Niño and What It Means for California

The El Niño is cooling off. A region of stormier equatorial weather, called a Mad­den Julian Oscillation, is flowing from the Western Tropical Pacific into the warm El Niño. It is churning the waters and cooling them down. While the key central measur­ing area of the El Niño is only one tenth of a degree cooler than last month, the outer edges of the event are much cooler. While the central region has the temperatures and characteristics of a strong event, the western side is only moderate in strength and the area off the coast of South America is so cool that it barely qualifies as an El Niño.

This means the El Niño should continue to act like a strong event for most of March. However, it is cooling more rapidly than many scientists expected. The majority of agencies still expect the event to be moderate in spring and end by June, but a closer look at the models seems to indicate a slight­ly quicker drop than they showed last month. Officially they give 50% odds of a La Niña developing in autumn, but private conversations indicate that unofficially the number is closer to 75%. Of the scientist expecting an La Niña the majority predict the cooler weather event to hit towards August or September.

This is important for North America, since the El Niño typically creates addi­tional rainfall in several areas that have been suffering from years of drought. Of­ficially this El Niño event began on March 1, 2015, when 52%, more than half of the “lower 48” US was dry and almost a third of the states were in drought. The event re­duced the drought throughout all but the westernmost states. If El Niño continues into springtime, history suggests it would bring more heavy rains, adding water to California and possibly, once again, elimi­nating water deficits in Texas.

Notice, despite expectations, the El Niño has not brought ex­cess rainfall to drought stricken California. Indeed, as it did in the strong 1972/73 event, it has delivered below average moisture for the southern por­tion of the state. Even though a continued El Niño can his­torically be expected to create a “Miracle March” or “Amaz­ing April”, the rain will merely provide some respite from the prolonged drought, not an end to the shortage.

David Fuller's view

Here is a PDF of this superbly illustrated report.

Any easing in the California drought would certainly be welcome and probably help to keep food price inflation in check.

As the title suggests, The Browning World Climate Bulletin provides global coverage so your approximate region is likely to be covered.