South Florida Sun-Sentinel (Sunday)
Odds of season’s next tropical depression rise
After over a month of calm, formation could occur in days
A region of rainy weather in the middle of the Atlantic Ocean stands a 40% chance of forming a tropical depression, the first in more than a month, the National Hurricane Center said Saturday.
The region is one of three areas of the Atlantic being watched for possible formation of a tropical cyclone, a rotating storm system that could range in strength from tropical depression to tropical storm to hurricane.
The system closest to the United States lies just east of the Caribbean Sea and has just a 10% chance of forming a cyclone, the hurricane center said its 2 p.m. Saturday update. The farthest system, located off the African coast, faces strong crosswinds and cooler water, giving it a 30% chance of formation.
But a “small but well-defined area of low pressure” in the middle of the Atlantic will encounter favorable conditions for storm formation and may become a tropical depression by the middle of this week, the hurricane center said. It’s expected to be moving west-northwest by the time it may form a depression.
If it develops it would be the first tropical cyclone to form in the Atlantic in more than a month, since the July 1 appearance of the storm system that would become Hurricane Elsa. The number of storms is likely to increase in frequency over the next few weeks, as the season ramps up toward its September peak.
It’s too soon to say whether this one would be a threat to land. If the system reaches tropical storm strength, it would get a name. The next two names on the list are Fred and Grace.
The area off the Cabo Verde Islands is a traditional spawning ground for cyclones during the peak of hurricane season. The frequency of storms starts increasing in early August and reaches its high point around Sept. 10.
AccuWeather, the private forecasting service, said storm activity in the Atlantic may be picking up after a month of quiet.
Conditions over the Atlantic have grown more favorable for storm formation, with a decline in the factors that can shut down storms, AccuWeather said. There has been a decline in wind shear, the high-altitude crosswinds that can tear up storms, and a decreased concentration of the dry, dusty air that can inhibit storm growth.
“We have been seeing a decline in the extent of dry air and dust over the zone from Africa to the Caribbean this week,” AccuWeather senior meteorologist Rob Miller said in a statement Friday.
Disturbances that emerge over or off Africa’s west coast are closely watched by the National Hurricane Center because it is a central spot that spawns the majority of Atlantic hurricanes that emerge in August. These disturbances generally move west across the Atlantic Ocean toward the Caribbean.
This hurricane season is expected to produce an above-average number of storms.
A pessimistic revision to NOAA’s Atlantic hurricane forecast released Wednesday predicts seven to 10 hurricanes, up from the preseason forecast of six to 10. The agency’s Climate Prediction Center agency predicts a total of 15 to 21 named storms, which means those with winds speeds of at least 39 mph, up from its earlier prediction of 13 to 20. The number of expected major hurricanes, which means those with winds of at least 111 mph, held steady at three to five.
“With less interruptive winds in place, tropical storms and hurricanes can more easily become better organized — as opposed to during an El Niño year when winds can keep systems in check,” according to AccuWeather.
So far this season, there have been four tropical storms and one hurricane. Hurricane Elsa formed a month ago before weakening to tropical-storm strength and hitting Florida’s Gulf Coast.
On average, fifth-named storms usually form in late August, according to AccuWeather.
Last year, by the end of hurricane season on Nov. 30, meteorologists cataloged 30 named storms — the most recorded in a single year.