Asia and the Pacific Islands are getting slammed by the tropics this year, as storm after storm spins up and tears toward land, threatening millions with ferocious winds and dangerous surges of water. Here in the U.S., though, it’s quiet—almost too quiet—and it’s likely going to stay that way for a little while longer.
The Pacific’s Hoppin’
Hurricanes need very warm waters, calm winds, ample disturbances (as a nucleus for development), and high levels of tropical moisture in order to form, survive, and thrive. These conditions are easier to come by in the Pacific than the Atlantic, so they’re at risk for typhoons all year round. The western Pacific typically sees many more tropical cyclones than we do in our part of the world, but this year the basin is teeming with activity, teetering on the verge of earning the CNN-ready title “hyperactive.”
A measure called Accumulated Cyclone Energy, or ACE, is a good way to look at the longevity and power of tropical cyclones—a category four hurricane that rages for a week will have a much higher ACE than a tropical storm that’s only around for twelve hours. We can judge how different seasons stack-up against each other by measuring the ACE for each; seasons with higher ACE likely saw stronger, longer-lasting, and more numerous cyclones.
According to WeatherBELL, in an average year, the ACE through July 10 in the western Pacific is 49. As of about 1:00 PM EDT today, the year-to-date ACE in the western Pacific was 164.89, or 336% higher than normal. The year-to-date ACE in the eastern and central Pacific basins combined is 291% higher than normal. That’s...significant!, even for July 10. The climatological average ACE for the western Pacific is 302, so with five-and-a-half months to go, we’re a little more than half way to average.
To put that into some perspective, the 2005 Atlantic hurricane season was the basin’s most active ever recorded—28 named storms—and the seasonal ACE was only 250, also the highest ever recorded in that basin. A normal year in the western Pacific exerts more energy on average than the strongest season ever recorded in the Atlantic.
And we thought we had it bad.
Conga Line of Storms
If that’s just a bunch of numbers to you, look at this afternoon’s satellite image for a visualization of the abundance of evaporated paradise:
Seven systems all at once, stretching from Mexico to China. The most serious storm among them is Typhoon Chan-Hom, which is likely going to make a direct hit on Shanghai soon with strong winds, heavy rain, and storm surge which could cause major issues for the many people and buildings in low-lying areas. Typhoon Nangka, a much stronger storm, will post a threat to Japan in a couple of days.
Over in the central Pacific, the office in Honolulu is tracking three systems—the remnants of Ela, which just fell apart north of the state, along with two tropical depressions just south of the island chain which will likely become tropical storms over the next couple of days, threatening nothing but some fish and ships.
Finally, in the eastern Pacific, we have two invest areas—disturbances being monitored for tropical development—that have a high likelihood of turning into tropical depressions over the next day or two. The one farther out to sea will likely stay there, but the one closer to land has the opportunity to develop into an interesting system if the latest models are accurate. It remains to be seen how far away from Mexico it will stay, but it’s something that the area should keep a close eye on.
Meanwhile, over in the Atlantic...
Nothin’. That’s not too abnormal, of course, since we’re still at the very beginning of hurricane season around these parts. Even though the season officially begins on June 1—and we’ve already seen two storms in Ana and Bill this year—things really don’t get jumping until August and September.
It doesn’t help that an enormous Azores High is suppressing the atmosphere like a nasty dictator, or that constant influxes of dry, dusty air from the Sahara are making the Atlantic a rudely inhospitable place for many thunderstorms to develop, let alone tropical cyclones. Waters are actually a little warmer than normal off the coast of North America, but it doesn’t look like we’ll see much for the time being.
Not that that’s a bad thing, of course.
Yo soy...El Niño
It finally happened! That gigantic El Niño predicted to unfold a year or two ago is starting to get its act together. The waters of the eastern Pacific are steaming, and all indications point to an El Niño could continue strengthening and become one of the strongest recorded in a very long time.
An El Niño occurs when the trade winds in the Pacific stop or shift directions, allowing warm water to flow east and pile-up off the northwestern coast of South America. This region typically experiences upwelling—cold, deep ocean water rising to the surface—which keeps gives the area pretty calm weather most of the time. This sudden oceanic warming upends the atmosphere, among other changes shifting the jet stream and allowing powerful storms to take shape in this region of the world.
That altered jet stream could be great news for the western United States if the feature continues through the winter, and it’s also good news for those of us who live near the Atlantic Ocean. Hurricane activity in the Atlantic during El Niños gets crushed like a grape due to enhanced wind shear flowing over the basin. Wind shear blows the tops off the thunderstorms, preventing them from growing and developing. El Niño events also tend to increase hurricane activity in the eastern Pacific, though, so it could be a rough year on the western coast of Mexico.
It’s not over just yet...
Forecasters still expect a handful of tropical storms and hurricanes in the Atlantic this year, so don’t let your guard down if you live along or near the coast. Even an extremely quiet hurricane season can produce a disaster. 1992’s Hurricane Andrew was the season’s first named storm, and it didn’t form until the end of August.
If you average together all of the hurricane forecasts issued at the beginning of the season, experts still expect somewhere around seven and nine named storms (including Ana and Bill). It’s something we’ll have to take day by day, but it looks like we’re in the clear for a little while longer, at least. Use that time to get prepared just in case.