Back in May, NOAA’s 2015 hurricane prediction called for 6 to 11 named tropical storms, 3 to 6 of which would grow to category 1 or 2 hurricanes, and of those, perhaps 2 would become major hurricanes (category 3-5).
Two and half months and only one hurricane later, NOAA released its revised forecast on August 6, 2015, announcing it was 90% sure this year would be another below-normal season with even fewer storms:
- 6-10 named tropical storms
- 1-4 category 1 or 2 hurricanes
- 1 Major hurricane
Recent Storm History
The Atlantic has had only 4 tropical storms (Ana, Bill, Claudette, and Erika) and only one hurricane (Danny). Tropical Storm Ana came ashore in South Carolina on May 10; Bill landed near Houston, Texas on June 16. Claudette formed on July 13 in the Atlantic Ocean 500 miles away from the US coast only to dissapate the next day.
Data from the two most recent storms, Hurricane Danny and Tropical Storm Erika, may show the effects of El Niño at work.
Hurricane Danny evolved from a tropical depression to tropical storm on August 18. It struggled to remain intact against a persistent mid-oceanic trough across the Caribbean region, strengthening to a Category 1 hurricane on August 20. But for the next three days, wind shear with drier air robbed energy from Danny, down-grading it past tropical storm status until August 24 when it dissipated just west of the island of Guadalupe on the Leeward Islands.
Tropical Storm Erika began organizing a little further west of where Danny began and has followed a similar track. As of the morning of August 27, 2015, NOAA reported the storm had strengthened overnight but was facing wind shear problems from an upper level trough in front of it to the west. Though producing 2-4 inches of rain, Erika remains poorly organized. If the storm survives the next 48 hours, it could rebuild itself with more favorable wind patterns as it passes over warmer waters.
How El Niño in the Pacific Disrupts Hurricanes in the Atlantic
NOAA cites the emerging El Niño as creating global weather patterns that disrupt the formation of hurricanes in the Atlantic ocean. This year’s El Niño is expected to be one the strongest ones on record, exerting effects on temperature and precipitation during late fall or early winter this year. While an El Niño comes about due to warm water in the Pacific Ocean, its warm water affects wind circulation patterns world-wide (known as the “ Walker Circulation”).
Tropical storms and hurricanes develop in calm, warm waters. So far, the warm all that warm El Nino water in the Pacific has spawned 8 hurricanes and 2 tropical storms. Hurricane Jimena and Tropical Depression Fourteen-E are currently active. Hurricane Jimena is now fully developed southeast of Hawaii while TD Fourteen-E s south of the Baja Penninsula heading north.
Usually for Atlantic hurricanes, the calm, warm waters off the west coast of Africa are perfect hurricane nurseries. Storm systems swirl, build, and blow westward to the calm and sometimes warmer Caribbean. However, an El Niño adds vertical wind shearing in the Caribbean and this disrupts and dissipates the heat energy. Not only does an El Niño inhibit hurricane formation, it also can blow-out those that do form.
But… It’s STILL Hurricane Season!
Right now is the peak of the Atlantic Hurricane season. ANY storm has the potential to be dangerous so it’s vital to stay prepared. Keep your family safe during these waning summer days. Be sure to check out our guide for hurricane preparedness, the “How Hurricanes Impact You” infographic.