Hurricane Florence is now a category 4 hurricane with maximum sustained winds near 140 mph.

It is forecast to remain an extremely dangerous major hurricane through Thursday.

The National Hurricane Center said Monday the monster storm continues to intensify and will be close to Category 5 strength by Tuesday. A Category 5 storm has the potential to cause catastrophic damage.

Storm surge watches could be issued as early as Tuesday morning.

Live storm tracker: See active storms in Atlantic

Thousands in North Carolina have been ordered to evacuate as the hurricane approaches.

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Residents in the forecast path were warned storm surge and prolonged, exceptionally heavy rainfall from Florence could be life-threatening.

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Hurricane Isaac is forecast to move into the eastern Caribbean Sea Thursday.

Helene strengthened as expected this morning, with winds increasing to 105 mph. It's forecast to weaken Wednesday morning in the mid Atlantic.

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There's also two tropical waves out there. The one in the western Caribbean could become a tropical depression late this week when it moves into the Gulf of Mexico.

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Hurricane Florence

Hurricane Florence remains a major hurricane, with 140-mph winds.

Location: 465 miles south-southeast of Bermuda and about 1,085 miles ESE of Cape Fear, North Carolina

Maximum sustained winds: 140 mph

Movement: west-northwest at 13 mph

Maximum sustained winds: 140 mph Movement: west-northwest at 13 mph Hurricane Florence interactive tracking map

At 11 p.m., the eye of Hurricane Florence was located 1,-85 miles east-southeast of Cape Fear, North Carolina.

Florence is moving toward the west near 13 mph. A west-northwest motion with an increase in forward speed is expected during the next couple of days.

A turn toward the northwest is forecast to occur late Wednesday night.

Interests in the southeastern and mid-Atlantic states should monitor the progress of Florence. Storm Surge and Hurricane watches are likely be issued for portions of these areas on Tuesday.

On the forecast track, the center of Florence will move over the southwestern Atlantic Ocean between Bermuda and the Bahamas Tuesday and Wednesday, and approach the coast of South Carolina or North Carolina on Thursday.

Satellite data indicate that maximum sustained winds have increased to near 130 mph, with higher gusts.

Florence is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale.

Further strengthening is anticipated, and Florence is expected to be an extremely dangerous major hurricane through Thursday.

Hurricane-force winds extend outward up to 30 miles from the center and tropical-storm-force winds extend outward up to 140 miles.

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Swells generated by Florence are affecting Bermuda and portions of the U.S. East Coast. These swells are likely to cause life-threatening surf and rip current conditions.

Hurricane Isaac

Hurricane Isaac is showing little change in strength as it approaches the Caribbean. It actually got a little weaker late Monday, with winds dropping to 70 mph.

Location: 960 miles east of the Lesser Antilles

Maximum sustained winds: 70 mph

Movement: west at 16 mph

Interactive map of Atlantic hurricanes

At 11 p.m. Monday, the center of Hurricane Isaac was located 960 miles east of the Lesser Antilles

Live storm tracker: See active storms in Atlantic

Isaac is moving toward the west near 16 mph. A westward motion with a slight increase in forward speed is expected through the end of the week.

On the forecast track, Isaac should move across the Lesser Antilles and into the eastern Caribbean Sea on Thursday.

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Maximum sustained winds are near 70 mph, with higher gusts.

Weakening is forecast to begin by the middle of the week as Isaac approaches the Lesser Antilles.

Hurricane-force winds extend outward up to 10 miles from the center and tropical-storm-force winds extend outward up to 45 miles.

Hurricane Helene

Hurricane Helene is strengthening rapidly as it moves away from the Cabo Verde Islands.

Location: 535 miles west of the Cabo Verde Islands and about 1,620 miles south of the Azores

Maximum sustained winds: 110 mph

Movement: west-northwest at 12 mph

Interactive map of Atlantic hurricanes

At 11 p.m. Monday, the eye of Hurricane Helene was located 535 miles west of the Cabo Verde Islands.

Helene is moving toward the west-northwest near 12 mph. A continued west- northwestward motion with a decrease in forward speed is expected through late Tuesday, followed by a turn toward the northwest and then toward the north-northwest on Wednesday and Thursday.

Maximum sustained winds have increased to near 110 mph, with higher gusts. Some additional strengthening is expected today.

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Steady weakening is forecast to begin by late Tuesday.

Hurricane-force winds extend outward up to 35 miles from the center and tropical-storm-force winds extend outward up to 105 miles.

Tropical waves

Showers and thunderstorms over the northwestern Caribbean Sea and western Cuba, associated with a surface trough, are showing some signs of organization.

This system is forecast to move slowly northwest near the Yucatan Peninsula on Tuesday with limited development.

Upper-level winds are forecast to become more conducive for development on Wednesday when the system moves over the southern Gulf of Mexico, and a tropical depression could form on Thursday or Friday while the disturbance moves across the western Gulf of Mexico.

Residnets across northeastern Mexico and the coast of Texas and Louisiana should monitor the progress of this system. Regardless of development, heavy rainfall and gusty winds are likely over western Cuba through Tuesday.

Formation chance through 48 hours: near 30 percent.

Formation chance through 5 days: 50 percent.

2. A non-tropical area of low pressure is forecast to form in the northeastern Atlantic Ocean several hundred miles west-southwest of the Azores in about two days.

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Environmental conditions are conducive for some development, and a tropical or subtropical depression could form by the end of the week while the low moves erratically over the northeastern Atlantic Ocean.