As the graphic shows, in the active MJO region, air currents rise over warm waters, causing clouds to form in big convection cells. So the MJO in this case spun off a piece that formed the core that started to rotate and pull in moisture from the outside. But there’s also simply the day-to-day vagaries of winds, ocean currents, temperature, etc. 22, 2016: After I posted this story, I became aware of a bit of a debate about whether Winston really was the strongest cyclone on record in the Southern Hemisphere.Meanwhile, convection activity is suppressed behind and ahead of this area of increased storminess. all tropical storms and hurricanes seem to require some form of finite amplitude disturbance to help get the vortex going . And were it not for those, the trip might not have been so strange. Jason Samenow at the Washington Post’s Capital Weather Gang addresses this issue in this excellent overview: According to records from the Joint Typhoon Warning Center, Winston ranks as the strongest on record to occur in the Southern Hemisphere.Here was the headline (click on it to go to the story): In that piece, I offered meteorologist Jon Gottschalck’s explanation of the MJO. One more thing is missing: good old-fashioned day-to-day natural variability, aka “weather.” What role did it play? He was born as a tropical storm on February 10, then wandered south, got stronger, got weaker, turned to the northeast, got stronger, stronger still, took an about face, etc…It is, he said, “an eastward moving disturbance of clouds, rainfall, winds, and pressure that traverses the planet in the tropics and returns to its initial starting point in 30 to 60 days, on average.” Click on the thumbnail to the left for a graphic that explains what happens once the active MJO region has moved east from the Indian Ocean, past Southeast Asia, and out toward the central Pacific. This evolution certainly was shaped by the bigger patterns we’ve just discussed.
As Climate Central’s Brian Kahn explains it: Global SSTs have increased by about 0.7 C since the 1970s, and water vapor over the oceans is up by 6% or more . The Madden-Julian Oscillation has also played role, but unlike El Niño — which sticks around for a year or more — the influence of the MJO on a given region in the Pacific passes in a matter of a couple weeks.He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine.Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.We’re also in the midst of something called the “Madden-Julian Oscillation,” which is intra-seasonal in nature, meaning it comes and goes in a matter of weeks.
And right now, the MJO is bringing enhanced storminess to the central and western Pacific — including the area where Winston spun up.
This is the story of Winston’s birth and evolution, and the factors that helped turn it into one of Earth’s fiercest storm’s on record.