El Niño que gritó ¡El lobo, el lobo!

By James Done, NCAR.

California is basking in 90degree heat this February while the Eastern Seaboard shivers through winter’s grip. This is not what the U.S. normally expects from El Niño. Is El Niño crying wolf?

El Niño has been strong since early July 2015 with widespread global impacts. Drought and agricultural fires in Indonesia were the world’s most expensive natural disaster of 2015 resulting in estimated losses of $16bn USD, and these impacts extended down into Northern Australia. Over in the Pacific, the 2015 tropical cyclone season saw record numbers of storms across the Pacific and record storm intensities. Patricia, the strongest Western Hemisphere hurricane on record, produced 200mph surface winds. Southern Brazil, Paraguay, Uruguay, and northern Argentina experienced some of the worst flooding in 50 years, with over 150,000 displaced people and extensive crop damage. Heavy rains west of the Andes brought substantial disruption to copper mining and several deaths from landslides in Chile. Further north, hot, dry conditions brought Amazonian fires and severe droughts in Guatemala, El Salvador, Honduras, Nicaragua and Cuba.

It’s clear El Niño has already contributed to enormous global disruption. What’s to come?

The current El Niño differs from a typical El Niño in that record warm temperatures extend well into the central equatorial Pacific Ocean, leading to a larger body of warm water than normal. Some have linked this to the disappointing winter rains over Southern California. While a much-anticipated parade of storms poured much needed water into California the amounts have fallen short of expectations over Southern California.

Given the strong El Niño forecast for Feb-Mar-Apr, there is a good chance that many of the classic El Niño global weather patterns will occur. For the U.S., a warm signal extends across Western and Northern States, with the strongest signals over the Pacific Northwest and the Upper Midwest coincident with a dry signal, while a cool signal extends across Southern States coincident with a wet signal. However, El Niño isn’t the only show in town.

Sudden warmings of the upper atmosphere above the Arctic herald the possibly of further cold blasts at subtropical locations, including the U.S., temporarily interrupting typical El Niño weather patterns. Another wild card is a mode of subseasonal variability known as the Madden-Julian Oscillation that can also temporarily disrupt typical El Niño weather patterns. However, like a magnet, El Niño will strive to pull the weather patterns back in line.

It seems that this spring, we should listen to El Niño.