Forecasts: US still on track for ‘above average’ Atlantic hurricane season

Posted at 8:08 AM, Aug 07, 2017
and last updated 2017-08-09 15:15:55-04

Warm sea surface temperatures and a weak or non-existent El Niño will contribute to an above-normal hurricane season in the Atlantic this year, Colorado State University announced Friday.

CSU predicting 16 named storms — including the five that have already occurred in addition to eight hurricanes and three major hurricanes.
The seasonal outlook from CSU agrees with the one the National Oceanic and Atmospheric Administration (NOAA) released just before the hurricane season began on June 1. NOAA’s outlook called for 141 to 19 named storms, five to nine hurricanes and two to five major hurricanes.

The season has been above average so far this season with respect to the number of storms, with five named storms by July 31. On average, the fifth named storm does not occur until August 31.

Even though the calendar says we are over one-third of the way through the hurricane season that runs from June 1 through Nov. 30, we are just getting into the busiest part of the hurricane season. In fact, over 75% of the named storms come during the peak months of August, September, and October.

As if on cue, the tropical Atlantic looks to be heating up this week, with two areas of potential development we are currently watching.

The closest disturbance to the United States, located in the southern Caribbean, could become a tropical storm by early next week and make its way into the southern Gulf of Mexico.

Farther to east, another cluster of storms in the eastern Atlantic looks to be organizing and “a tropical depression is likely to form by the early or middle part of next week,” according to the National Hurricane Center. The system will move towards the west and should approach the Lesser Antilles by the middle of next week.

The prediction of “above normal, or near normal” storm activity will likely put coastal residents on edge. This year marks the 25th anniversary of Hurricane Andrew — one of the most devastating storms ever recorded — and that came during a below-average season. That should give people pause — and remind them to make a plan and be prepared.

“This season has had a running start,” according to Ben Friedman, acting NOAA administrator. Tropical Storm Arlene formed briefly in April in the north-central Atlantic. An extremely rare occurrence, Arlene was just the second named storm on record for the month of April.

The lack of El Niño is to blame

Forecasts made earlier this year were predicting “slightly below-average activity.” These forecast were made in early April when a weak to moderate El Niño was forecast to develop during the peak of hurricane season. Now that we are more likely to enter and maintain neutral conditions of the El Niño Southern Oscillation in the Pacific, recasters believe we will see an above average season.

El Niño is a naturally occurring phenomenon characterized by warmer than normal water in the eastern Pacific equatorial region. While El Niño occurs in the Pacific Ocean, it has widespread impact on the global climate. One of the elements affected is increased wind shear across the tropical Atlantic, which creates hostile conditions for tropical development.

With a lack of El Niño taking shape, Colorado State forecasters say there’s a 62% chance of a major hurricane making landfall in the United States this season. The average risk is 52%.

Record-breaking major hurricane drought

Amazingly, the US has not experienced a major hurricane — a Category 3 or higher, with sustained winds of 111 mpg and higher — landfall since Hurricane Wilma in 2005.

“The odds of going 11 years without a major hurricane landfall in the US is around 1 in 2,000,” said Phil Klotzbach, a hurricane research scientist at Colorado State University.

“Roughly 25% of major hurricanes that form in the Atlantic make a US landfall,” he added. “We have had 31 major hurricanes since Wilma in 2005. The odds of having 31 major hurricanes form in the Atlantic with zero landfalls would be around 1 in 7,500.”

That streak nearly ended last year with Hurricane Matthew.

After several quieter seasons, 2016 was above normal, as expected, with 15 named storms, seven hurricanes and four major hurricanes. Hurricane Matthew had the greatest impact, with its center passing just offshore of eastern Florida and Georgia as a major hurricane, before making landfall in South Carolina as a Category 1 storm and bringing historic flooding to North Carolina.

There was also Hurricane Hermine, which became the first hurricane to make landfall in Florida in 11 years, the state’s longest hurricane-free streak.

“There is a potential for a lot of Atlantic storm activity this year. We cannot stop hurricanes, but again, we can prepare for them,” said Friedman.


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