Why hurricane season is about to get busier

Hurricane activity is expected to pick up in the weeks ahead, as forecasters monitor conditions that could fuel a busy back half of the season in September and October.

The National Hurricane Center is monitoring a disturbance in the eastern Atlantic Ocean, giving it an 80% chance of becoming a tropical storm in the next week.

It’s too early to say exactly where the potential storm would go, but people living in the Caribbean Islands should keep a close eye on developments, as it may approach next week.

If it forms, it would become the seventh named storm so far this season, which technically runs through November. Of the six storms that have already formed, just one strengthened into a hurricane – Erin – whose journey spanned nearly 7,000 miles across the Atlantic.

The possible re-emergence of La Niña during the months ahead, as well as unusually warm ocean temperatures in the Atlantic, could boost hurricane activity through November. La Niña tends to reduce the level of wind shear in the Atlantic, or the tendency for winds to twist and increase with height, creating conditions that are more conducive for forming storms.

Meteorologist Andy Hazelton said he thinks the Atlantic will generally become more active in the weeks ahead, citing a pattern – called the Madden-Julian Oscillation – that will probably generate more thunderstorms that can grow into tropical storms.

Early Wednesday, the disturbance being monitored was a cluster of showers and thunderstorms south of the Cabo Verde islands – more than 2,000 miles away from the Lesser Antilles.

Some weather models show the system intensifying into a tropical depression or storm late in the week or over the weekend.

It will generally track westward over the coming week, along the southern flank of the storm-steering Bermuda high pressure system.

The strength of the high will influence how far south or north the storm goes. In recent days, it has been trending stronger, which may give the storm more of southerly trajectory during the week ahead – which is why people living in the Caribbean should keep an eye on the situation.

It’s too early to speculate on any possible impact in the United States or elsewhere, because circulation patterns that conduct the future storm’s movement cannot be accurately predicted so far in advance.

The next storm names will be Gabrielle, Humberto and Imelda.

A moderate-to-strong marine heat wave spans the Atlantic, with water temperatures several degrees above-average for the time of year.

Some of the most unusually warm waters – storm fuel – are in the Caribbean Sea, near the Bahamas, Florida and the Gulf of Mexico.

Because it’s the focal point of warm seas and fewer storms emerge from Africa by this time, hurricane tracks typically favor the western part of the basin during October, so this unusual oceanic warmth is of particular concern for southern states.

In August, the National Oceanic and Atmospheric Administration issued a La Niña watch. Cool waters in the tropical Pacific Ocean – a hallmark of La Niña – can reduce the level of clouds and thunderstorms there while enhancing it over the Atlantic.

A pulse of storm activity that regularly swirls around the planet, called the Madden-Julian Oscillation, is predicted to reach the Atlantic in mid-to-late September. Its potential will probably be enhanced by unusually warm ocean waters in the Atlantic and the developing La Niña in the Pacific.

Because of these factors, the calm in the Atlantic won’t last much longer.

“I expect things to pick up and for the bulk of our seasonal activity to occur in the next few weeks,” Hazelton said.

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Hurricane season so far

There have been six named storms so far this season, which is about normal for early September.

A typical Atlantic hurricane season features a total of 14 named storms, seven hurricanes and three major hurricanes.

The latest forecasts from NOAA and Colorado State University maintain that an above-average number of named storms is most likely this season, which runs through November.

Colorado State expects a “slightly above-average probability for major hurricanes making landfall along the continental United States coastline and in the Caribbean” this hurricane season, echoed by other meteorologists who predict that the East Coast is at greater risk for a landfalling storm.