Isaac downgraded to tropical storm, still poses danger for Caribbean islands

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VIIRS found coldest cloud top.

Often the greatest threat from a hurricane is the storm surge. The government of France has discontinued the Tropical Storm Watch for St. Martin, and the government of St. Maarten has discontinued the Tropical Storm Watch for St. Maarten.

What is Vertical Wind Shear?

Wind speeds are expected to hit 55-65mph, with maximums of 70-80mph. In order to understand how it affects a tropical cyclone or hurricane, think of a tropical cyclone as a series of vertically stacked tires, all rotating. "Even if you've ridden out storms before, this one is different".

Tropical Storm Isaac appeared "poorly organized" and was weaker on the early morning hours of Wednesday Sep.

"Areas of low pressure containing what's left of Storm Helene will still provide moisture and energy which will impact the United Kingdom quite a bit as we go into the early part of next week".

High temperatures will be well above the average of 91 degrees.

The Hurricane Centre says Isaac is almost completely devoid of deep convection at the moment and is not trackable in radar data from Guadeloupe and Martinique.

A tropical storm warning is in effect from Duck, North Carolina, to the North Carolina/Virginia border, with a watch in effect from there to the Chesapeake Bay south of New Point Comfort.

Coastal watches and warnings have been canceled. Then on Sunday, as a weakening Florence moves away from our region, our winds will gradually weaken during the day, with some wraparound showers possible. This general motion is forecast to continue today with a decrease in forward speed as it gets over the Caribbean Sea. Nonetheless Helene is bringing with her very strong wind with gusts up to 120km/h, heavy rain and waves of between 6 and 8m high on some islands. Although the storm is expected to weaken, it has followed a wavering path and could still pose a threat to Cayman early next week.

The NHC at 11 a.m. on September 12 has issued warnings for Tropical Storm Isaac, which is still moving west about 420 miles east of the island of Martinique.

The storm is expected to produce 3 to 5 inches of rain across Martinique, Dominica, and Guadeloupe, with near 10 inches possible in isolated areas, forecasters said. This rainfall may cause risky flash flooding, N.H.C. said.

The U.S. National Hurricane Center (NHC) said Helene has 90 miles per hour winds, meaning it is a Category 1 storm.

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