Isaias, A Hurricane Again, To Bring 70 MPH Winds To LI Tuesday

UPDATE 9 a.m. Tuesday: Tornado Watch Issued For Long Island

Isaias strengthened back into a hurricane Monday night. The storm, with maximum sustained winds of 85 mph, is expected to make landfall in the Carolinas overnight. A tropical storm warning is in effect for Long Island.

Isaias will slowly weaken as it accelerates northeast Tuesday, the National Hurricane Center says, but it will still packing a punch when it nears Long Island.

Rain will likely begin after sunrise Tuesday and then pick up in intensity as the morning wears on. Up to 6 inches of rain is possible through Monday night on the island.

"The main threats with this system involve heavy rainfall, strong winds, minor to moderate coastal flooding, along with high surf and dangerous rip currents," the National Weather Service says. "Additionally, a few tornadoes are possible."

Tropical-storm-force winds are expected to lash Long Island starting Tuesday afternoon and continuing into early Wednesday. Sustained winds of 45-55 mph and gusts up to 70 mph are possible during the storm's peak.

PSEG Long Island said its latest projections show that the storm has the potential to cause a significant number of power outages.

"We now anticipate that this storm may be one of the strongest to reach Long Island in years and some outages could last for an extended period," PSEG said in an email to customers Monday evening.

"The energy grid is much stronger now than it was just a few years ago, but we are prepared to respond to any outages safely and as quickly as possible with our own crews and additional utility crews that we are bringing in from off-island."

There is an "elevated threat" of property damage along the South Shore of Nassau County and western Suffolk County, where a coastal flood warning will be in effect from 8 p.m. Tuesday until 8 a.m Wednesday. Widespread flooding of vulnerable areas near the waterfront and shoreline is likely.

Waves of 10-15 feet will likely result in considerable erosion of dune structures and localized over-washes along the ocean beachfront, the weather service says. This may cause some flooding of roadways and vulnerable structures behind protective dunes.

The full forecast:

Monday Night- A 40 percent chance of showers and thunderstorms, mainly after 8pm. Increasing clouds, with a low around 73. South wind 5 to 11 mph becoming northeast after midnight.

Tuesday- Tropical storm conditions expected. Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 79. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.

Tuesday Night- Tropical storm conditions possible. Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 72. Chance of precipitation is 80%. New rainfall amounts between three quarters and one inch possible.

Wednesday- A 30 percent chance of showers and thunderstorms, mainly before 8am. Partly sunny, with a high near 86. Southwest wind around 8 mph.

Wednesday Night- A 20 percent chance of showers and thunderstorms before midnight. Partly cloudy, with a low around 69. Southwest wind 5 to 9 mph becoming north after midnight.

Thursday- A 30 percent chance of showers after 2pm. Partly sunny, with a high near 83.

Thursday Night- A 40 percent chance of showers. Mostly cloudy, with a low around 68.

Friday- A 30 percent chance of showers after 2pm. Mostly cloudy, with a high near 82.

Friday Night- A 40 percent chance of showers. Mostly cloudy, with a low around 69.

Saturday- Partly sunny, with a high near 84.