Look out for little troublemakers. Small weather patterns in the Tropical Pacific can trigger tropical storms in the Atlantic. If a Madden Julian Oscillation (MJO) is in the wrong place, the Gulf of Mexico can churn up a hurricane.
So far, the Atlantic Hurricane Season has been delightfully quiet. Warm El Niño conditions developed in May and lingered into June. These conditions created high altitude winds that tended to cut down disturbances in the Atlantic before they could develop into tropical storms.
The peak of the Atlantic Hurricane Season has begun.
Then a small cool MJO flowed into the warm El Niño waters and churned them up. The Tropical Pacific cooled down and the high altitude winds disappeared just as the peak of the Atlantic Hurricane season arrived.
The Atlantic isn’t the only area in trouble. These MJOs flow west to east around the equator. Depending upon whether they are hot or cold, they make rain and tropical storms more or less likely. While one set of MJOs make Atlantic hurricanes more likely, another helps the Indian monsoon. Another will dry out Southeast Asia. They only linger in an area for a few weeks, but a few weeks of hurricane weather can seem a l-o-o-o-ng time.
Maps of MJO movements show where storms and droughts are most likely.
Already MJOs are affecting the Atlantic Hurricane season. After only two named tropical storms, (last year had five by the end of the third week of August), scientists warn that two small disturbances in the Atlantic might become storms. Some long-range models are making predictions that one of the storms might threaten New Orleans. (Models this long-range are seldom accurate, but they generate headlines.)
These models are experimental and, until a tropical storm actually develops, not very accurate—but isn’t it scary.
While we are getting very good at predicting the paths of developed tropical storms, it is hard to predict the paths of smaller disturbances. At the same time, we still have difficulty predicting how big the storms might become.
But if you are interested in hurricanes, (or want a storm to bring rainfall to drought-stricken parts of Texas), this is your moment. A little trouble-making MJO in the Pacific has brought down the protective El Niño conditions and it’s party time for tropical storms in the Atlantic.
Evelyn Browning Garriss, historical climatologist, is a longtime writer for The Old Farmer's Almanac. She is also editor of The Browning World Climate Bulletin and has advised farmers, businesses, and investors worldwide on upcoming climate events and their economic and social impact for the past 21 years.