Additional hurricanes, beyond that of Jose and Maria, are likely over the Atlantic and may threaten the United States for the rest of the 2017 season.
Hurricane season runs through the end of November, and it is possible the Atlantic may continue to produce tropical storms right up to the wire and perhaps into December.
“I think we will have four more named storms this year, after Maria,” according to AccuWeather Hurricane Expert Dan Kottlowski.
“Of these, two may be hurricanes and one may be a major hurricane,” Kottlowski said.
The numbers include the risk of two additional landfalls in the United States.
As of Sept. 18, there have been four named systems that made landfall, including Harvey and Irma that made landfall in the U.S. as Category 4 hurricanes. The other two tropical storms were Cindy, near the Texas/Louisiana border in June, and Emily, just south of Tampa, Florida, at the end of July.
Jose will impact the coast of the northeastern U.S. much of this week; Lee and Maria are in progress over the south-central Atlantic.
Lee will likely remain at sea and is not expected be a threat to the U.S. or any land areas.
However, Maria will have direct impact on some of the islands of the northern Caribbean and may reach major hurricane status this week. Maria will, at the very least, have indirect impact on the U.S.
On average, strong west to northwest winds with cooler and drier air tend to scour tropical systems out of the western Atlantic during October and November.
However, this year, AccuWeather meteorologists are concerned that these winds may not occur until later in the autumn or may be too weak to steer tropical threats away from the U.S.
The warm weather pattern that has developed over the Central states and expanded into the eastern U.S. is a product of that development.
Driving this warm weather pattern is a large area of high pressure, centered near Bermuda. The clockwise flow around this system will pump warm, humid air northward from the Gulf of Mexico and the western Atlantic.
Tropical storms and hurricanes that brew will get caught up in the flow around this high pressure area.
While interruptions in this flow and the warm and humid pattern are likely in the northeastern U.S., it will generally persist in key tropical development areas well into October.
“When we get a pattern such as this, we usually have two to three named storms in October and can have one in November or December,” Kottlowski said.
U.S. interests from the Gulf of Mexico through the Atlantic Seaboard should check in frequently on the latest in the tropics during this active season.
While past hurricanes in October have no bearing on what will happen this season, there have been some damaging hurricanes during the middle of the autumn in the eastern and southern U.S. These include Hazel in 1954, Wilma in 2005, Sandy in 2012 and Matthew in 2016.