2 Hurricanes Threaten US This Week

Hurricane Iselle was one of several tropical storms lacing the Pacific on Aug. 3.

(Image credit: NASA/NOAA GOES Project)

Two hurricanes threaten the United States this week. One is expected to completely miss the U.S. Atlantic Coast, however, while the other will weaken as it heads toward Hawaii.

Hurricane Bertha is the second hurricane to form in the Atlantic this season. The tropical storm arrived early: On average, the second hurricane of the Atlantic season occurs during the end of August, according to statistics kept by the National Weather Service. This is also the first time since 1992 that both of the first two tropical storms of the season strengthened into hurricanes. (Not all tropical storms become hurricanes.)

The National Hurricane Center (NHC) forecasts that Bertha, now a Category 1 hurricane, will move away from the Bahamas today (Aug. 4) and head northeast, passing offshore of the U.S. East Coast for the next five days. The hurricane is not predicted to make landfall and will likely miss the East Coast.

Bertha is blowing sustained winds of 80 mph (129 km/h) and is expected to start weakening by Tuesday. The storm is churning about 230 miles (370 kilometers) northeast of Great Abaco Island in the Bahamas. [Hurricanes from Above: See Nature's Biggest Storms]

In the Pacific, Hurricane Iselle is bearing down on Hawaii, though it is forecast to weaken from its current Category 4 strength before hitting the tropical islands. Iselle has sustained winds of 140 mph (225 km/h), according to the latest update from the NHC. Iselle is expected to lose strength and weaken to a tropical storm as it travels over cooler water and closes in on Hawaii by Friday morning (Aug. 8).

Iselle is currently located about 1,250 miles (2,010 km) east of Hawaii and is swirling west at about 9 mph (14 km/h).

Hawaii could face a one-two punch from tropical storms, as Iselle is also being followed closely by Tropical Storm Julio. Weather models suggest Julio will become a hurricane later this week, and then, following the path of Iselle, hit cool water and weaken before slamming into Hawaii. However, the storm's path is more uncertain than Iselle's at this point.

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook & Google+. Original article on Live Science.

Becky Oskin covers Earth science, climate change and space, as well as general science topics. Becky was a science reporter at Live Science and The Pasadena Star-News; she has freelanced for New Scientist and the American Institute of Physics. She earned a master's degree in geology from Caltech, a bachelor's degree from Washington State University, and a graduate certificate in science writing from the University of California, Santa Cruz.