It’s the height of summer in the Northern Hemisphere, and the oceans have never been hotter. What’s more, there’s increasing evidence that a warming feedback loop has been kicked off in recent days—which could quickly ramp up El Niño.
If you’re not a seasoned weather nerd, the feedback loop—warm water begets typhoons beget weird trade winds beget more warm water—is a bit tricky to follow in charts and maps. But its effects on El Niño could produce global ramifications.
Credit: Cameron Beccario/earth.nullschool.net
Here’s how it works: The El Niño weather pattern is a joint effort between the ocean and the atmosphere, and this week’s surge showcases the linkage.
El Niño means the tropical Pacific is warmer than normal, which improves the chances that typhoons will form. This week, a series of typhoons on both sides of the equator are helping to reinforce a big burst of westerly winds along the equator. These westerly wind bursts are a hallmark of El Niño, and help push subsurface warm water toward the coast of South America. If enough warm water butts up against Peru, the normal cold water ocean current there can get shut off, exacerbating the pattern.
Exactly how this all gets kicked off is an area of active research, but it’s clear that big El Niños need deviant trade winds to maintain the feedback loop. During especially strong El Niños, like this year’s promises to be, the trade winds can sometimes reverse direction—and this week’s off-the-charts wind surge is at record-strength for so early in an El Niño event. Since all this takes place in the tropical Pacific Ocean—the planet’s biggest bathtub—a fully mature El Niño has the power to shift rainfall odds worldwide and boost global temperatures. That’s exactly what’s happening this year.
As proof: An area of the central Pacific, straddling the equator, is now the warmest on record for this time of year, crushing the previous record. So far, the 2015 El Niño is strengthening at a rate equal to, if not slightly greater than some of the strongest El Niños since comprehensive ocean recordkeeping began in 1870.
On Tuesday, even as the official U.S. El Niño blog encouraged weather watchers to “keep calm,” new forecast data compiled by the National Oceanic and Atmospheric Administration gave the clearest indication yet that this year’s El Niño is heading for a new all-time record. Tuesday’s data factors in the initial stages of the Pacific’s westerly wind burst in June, boosting the likely peak water temperature later this year.
That warm water has already been spawning typhoons at a breakneck pace, with three storms currently bound for Asian shores. The biggest of the three, Typhoon Chan-hom, threatens Taiwan and mainland China later this week. Chan-hom’s massive cloud shield is now roughly the size of Alaska. So far, 2015 has been nearly three times as active as normal in the Pacific Ocean, and has already featured more storms of Category 5 strength than typically occur in an entire season, the bulk of which usually falls between July and November.
This week is poised to get even busier, with one weather model predicting off-the-charts activity over the next several days:
This chart pretty well sums up the current situation in the western/central tropical Pacific... pic.twitter.com/IP6OOpxGZk— Todd Crawford (@tcrawf_nh) July 7, 2015
The new Himawari-8, a Japanese weather satellite that officially came online Tuesday, is boasting some of the best space-based views of the Pacific typhoons ever seen. Meteorologists are ogling the new images, which come as rapidly as once every two minutes, making for impressively smooth animations (especially when compared with traditional imagery). If all goes well, the United States will have a new weather satellite with similar capabilities in early 2016.