This Thing Called MJO Is Spitting Out Nasty Weather Across GlobeBrian K. Sullivan
Anyone looking for evidence of the Earth’s larger connections doesn’t need to look any farther than the Pacific Ocean right now.
Four tropical systems are careening through the basin. Cyclones Nathan and Olwyn are bracketing Australia, Tropical Storm Bavi is headed toward Guam and Cyclone Pam, just to the east of Vanuatu, is on its way to becoming one of the largest systems to form in the South Pacific.
Pam’s sustained winds are forecast to reach 172 miles (277 kilometers) per hour Friday, based on measurements taken over one minute, according to the Joint Typhoon Warning Center in Hawaii, which is staffed by U.S. Navy and Air Force meteorologists.
“That is a pretty ridiculous storm,” said Jeff Masters, co-founder of Weather Underground in Ann Arbor, Michigan. “It’s still going bonkers. It’s going to be big trouble for some of the small islands.”
While the activity is impressive, there’s also evidence that, at least to a degree, it’s being driven by larger forces.
Take Bavi and Pam. The two storms have formed on either side of the equator and almost look like mirror images of each other.
When twin storms form like this, it’s often in response to a strong pulse in the Madden-Julian Oscillation, Masters said. The MJO is a burst of energy that moves through the atmosphere the way a ripple will run through a snapped bed sheet.
“This MJO will be one of the four strongest going back to 1974,” Masters said.
The same phenomenon will help strengthen a high-pressure ridge near Alaska that will egg on a low-pressure trough across central North America, dumping cold air into the U.S. next week.
Temperatures across the U.S. Northeast may drop 5 to 8 degrees Fahrenheit (2.7 to 4.4 Celsius) below normal from March 18 to March 27 as the MJO-enhanced cold pours down from Canada, according to a forecast by Matt Rogers of Commodity Weather Group LLC in Bethesda, Maryland.
There is even more going on here than the influence of the MJO. Last week, the U.S. Climate Prediction Center declared an El Nino had formed in the equatorial Pacific, which means sea-surface temperatures have risen above normal levels and westerly winds have picked up across the basin.
Westerly winds in that part of the world can help tropical systems get started, said Phil Klotzbach, lead author of Colorado State University’s seasonal Atlantic hurricane forecast. The storms then can enhance the westerlies, which in turn help sustain the El Nino.
“Basically, it’s a feedback,” Klotzbach said. “The same thing happened in 1997; there were storms on both sides of the equator for maybe 10 days.”
That year was also when the strongest El Nino in the past century formed, he said.
“It’s certainly not a guarantee that we are going to get a strong El Nino,” Klotzbach said. “We said the same thing last year and didn’t get an El Nino.”
If an El Nino does form, and it’s spurred on by these tropical systems, it could actually end up crimping the Atlantic hurricane season, which starts on June 1. The woes of the Pacific become the benefits of the Atlantic.
Meanwhile, back in Australia, Olwyn went ashore near Exmouth. It was forecast to take a track across Western Australia, weakening as it goes and passing to the east of Perth, the Typhoon Warning Center said.
On the other side of the country, Nathan is forecast to make a run at the northern part of Queensland before reversing course and heading back out to sea.