The tropical Atlantic will likely wake up soon. Multiple waves are forecast to emerge over the warming waters of the eastern Atlantic in the next few days, and one of them may approach the U.S. in about a week.
At least three disturbances, or tropical waves, are likely to move off the west coast of Africa over the next 7 to 10 days. While the waves appear to be unusually strong on forecast charts, they also show signs of struggling to stay in tact through the Main Development Region (MDR). Forecast data suggests atmospheric conditions will likely be too hostile through the central Atlantic, although some model runs suggest one or two of them may attempt to reorganize across the western Atlantic by late next week.
For several months, sea surface temperatures across the MDR have been unusually cool. Dry air, Saharan dust, and strong winds aloft have also contributed to an environment not favorable for tropical development in these regions. More recently, all of these inhibiting factors have waned a bit, but are still a potential roadblock to the typical tropical passageway to North America.
The peak of the Atlantic Hurricane Season is only a few weeks away, so it would be no surprise if the Atlantic becomes more active soon. As of August 24, five tropical storms have already formed, two of which became hurricanes. By the numbers, most forecasters believe the season will be less active than normal. While this may come true for the basin as a whole, where and when a particular storm may form or track really can't be forecast with credibility beyond a few days.
August 20 through October 10 is traditionally the most active 60-day period of the year in the tropics, according to Colorado State Scientist Doctor Phil Klotzbach. Nearly two-thirds of hurricanes and 75% of major hurricanes forming during that time.
Over 60% of #hurricanes and ~75% of all Atlantic major #hurricanes historically have formed between August 20 - October 10. pic.twitter.com/3HKZwA0oTQ
— Philip Klotzbach (@philklotzbach) August 20, 2018
The season got off to an early start. Subtropical Storm Alberto formed on May 25, making it the fourth consecutive year a named storm developed before the official start of the season, which is June 1st. Beryl became the first hurricane since 2008 to form in the Atlantic during the month of July. Four days later, on July 10, Chris became the second earliest hurricane to form in a season since 2005.
As of Friday, there have been no hurricanes during the month of August, and only two named storms had developed. Only eight times since 1966 has there not been a hurricane during the month of August with the most recent being 2013.
In a tweet earlier this week, NOAA reminded all residents along the U.S. Gulf & East coast are vulnerable to a hurricane, but that there are locations with “higher odds of being hit any given year”.
Every mile of the U.S. Gulf & East coast is vulnerable to a hurricane, but there are locations with higher odds of being hit any given year. We call it the hurricane return period. https://t.co/f3EolMQbCI #hurricaneprep #hurricanestrong pic.twitter.com/Mxh3LBCSBJ
— Natl Hurricane Ctr (@NWSNHC) August 20, 2018
South Florida and the Keys have some of the highest odds of being hit by a hurricane in the U.S, with an average return period of every five to seven years. It was only last year that Major Hurricane Irma came ashore near Marco Island, Florida, producing extensive damage from Key West to Jacksonville. The season doesn't officially end until November 30.