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Isaac takes aim at Haiti; tropical storm watch on for southern Florida

Those considered most vulnerable were urged to move into an evacuation camp housed in a school building, but others with nowhere else to go were digging trenches to avoid the water. Haiti's population remains especially vulnerable due to the country's sprawling shanty towns. NBC's Mark Potter reports.

Updated at 11 p.m. ET: Tropical Storm Isaac strengthened on Friday as its lashing rains took aim at flood-prone Haiti, but it was not expected to become a hurricane until it barreled into the Gulf of Mexico early next week. 

On its current path, forecasters said Isaac would hit Cuba and the southern tip of Florida before making landfall anywhere from the Florida Panhandle in the northwestern part of the state to Alabama and as far west as New Orleans.

Forecasters put the entire coast of south Florida under tropical storm watch as of 5 p.m. EDT (2100 GMT) on Friday.

But the biggest immediate concern was heavily deforested Haiti, where the U.S. National Hurricane Center (NHC) said the full force of the storm was expected to be felt later Friday.  

Isaac could pass near Florida's Gulf Coast early Monday just as the Republican National Convention is scheduled to start in Tampa. 

Winds at tropical storm strength extend 185 miles out from Isaac's center, the U.S. National Hurricane Center said in an afternoon advisory, making it a very wide storm.

On exiting Haiti, Isaac's center should cross Cuba on Saturday, and then pass south of the Florida Keys before making landfall as a Category 1 hurricane overnight Tuesday somewhere between New Orleans and Tallahassee, NBC meteorologist Al Roker said Friday on TODAY. Warm waters in the Gulf of Mexico will be "energy for the storm" as it makes its way across the gulf, he added.


In related developments Friday:

  • The U.S. embassy in Haiti sent an e-mail to American citizens in the country warning that flights into and out of Port-au-Prince have been suspended due to Isaac.
  • Oil and gas producers in the Gulf of Mexico started preparing as Isaac's track looked to skirt the heart of the U.S. offshore energy producing zone. BP said it would shut down its giant Thunder Horse platform, the world's largest. Royal Dutch Shell, Chevron and Apache Corp. said they would evacuate some workers from their Gulf platforms with no production impacts. Other offshore drillers were likely to shut production in coming days as the storm approaches.
  • The U.S. military moved 22 F-16s from Homestead Air Reserve Base in Florida to Fort Worth, Texas. Three F-15s from the base are on alert to move to Jacksonville if necessary.

How do you salvage vacation plans when a hurricane strikes? NBC's Chris Clackum reports.

South Florida could see a few twisters and heavy rain -- some 5-10 inches Sunday and into Monday, weather.com experts said in an online chat with readers Friday.

Florida has not been hit by a major hurricane since 2005 and officials are concerned that residents there have become complacent.

Aid workers prep Haiti's tent city residents for Isaac's onlsaught

"I think it's a challenge of getting people to understand their risk and make sure they’ve got a plan," said Craig Fugate, administrator of the Federal Emergency Management Agency.

With more than 19 million people living across the Sunshine State, Fugate wants every Florida resident to have enough supplies to last 72 hours and to know when to evacuate.

Click this image to get to our Atlantic storm tracker.

"I think the most dangerous thing is when people keep waiting to see what the next forecast is even if they’re in an evacuation zone. They say, 'Oh, it’s just a Category 1 storm or a minimum hurricane.' We’ve seen significant impacts from tropical storm force winds and rain," Fugate added.

In the Florida Keys, where there are few routes available for evacuation -- U.S. 1, Key West International Airport, and the Florida Keys Marathon Airport -- Mayor Craig Cates said his biggest concern was the storm's timing. Cates said he would need at least 36 hours to begin evacuations of tourists and residents.

"If it (Isaac) comes straight on to Key West, we’re worried about the damage that could happen in Key West. If it goes further up the Keys, it could damage power lines and we could get affected," Cates said. "Even if it hits further up the state, we have got to be prepared with our generators and our supplies. Being on an island, we understand that."

Forecasters with The Weather Channel think the evacuation decisions could come quickly. It is anticipated that watches will be issued for South Florida and the Keys by Friday night. In the event of an evacuation, Cates told The Weather Channel that tourists would leave first, followed by special needs citizens. 

Live updates and analysis from weather.com
Transcript of weather.com experts answering Isaac questions 

Florida Gov. Rick Scott said state officials are working with convention organizers, who will ultimately make the call on a delay or cancellation of the event.

State officials announced Thursday that they will wait to make decisions about moving supplies until after Isaac passes Cuba. FEMA has already placed food and generators in Jacksonville.  

Isaac is forecast to remain a tropical storm after crossing the Dominican Republic and Haiti and then passing over Cuba into the Florida Straits.

Tampa officials have not ruled out the possibility of postponing the GOP Convention if the storm poses a public safety risk. NBC's Kerry Sanders reports.

The National Hurricane Center warned it was "important not to focus on the exact track because of forecast uncertainties and the fact that Isaac has a large area of tropical storm force winds."

Follow Isaac's path with our storm tracker

Isaac was expected to dump between 8 and 12 inches of rain over parts of Haiti and the Dominican Republic, and up to 20 inches in a few areas. That poses a significant threat to Haiti, which is highly prone to flooding and mudslides because of its near-total deforestation.

Haiti, the poorest country in the Americas, still has about 350,000 people living in tents or makeshift shelters more than 2-1/2 years after a devastating earthquake that took more than a quarter of a million lives.

With nearly 400,000 people still living in evacuation tents, a hurricane or even a tropical storm could lead to deaths and more damage to the already fragile country. NBC's Mark Potter reports.

Red Cross workers toured crowded tent camps of Haitians left homeless by the 2010 quake to warn about Isaac.

Authorities in the Dominican Republic evacuated people living on the banks of rivers, streams and areas vulnerable to landslides in preparation for the approach of Isaac, whose effects were beginning to be felt with showers in the south of the country.

Weather.com and Reuters contributed to this report.

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