NEW ORLEANS — With its massive size and ponderous movement, a strengthening Isaac could become a punishing rain machine depending on its power, speed and where it comes ashore along the Gulf Coast.
The focus has been on New Orleans as Isaac takes dead aim at the city seven years after Hurricane Katrina, but the impact will be felt well beyond the city limits. The storm's winds could be felt more than 200 miles from the storm's center.
The Gulf Coast region has been saturated thanks to a wet summer, and some officials have worried more rain could make it easy for trees and power lines to fall over in the wet ground. Too much water also could flood crops, and wind could topple plants like corn and cotton.
"A large, slow-moving system is going to pose a lot of problems -- winds, flooding, storm surge and even potentially down the road river flooding," said Richard Knabb, director of the National Hurricane Center in Miami. "That could happen for days after the event."
However, Isaac could bring some relief to places farther inland where farmers have struggled with drought. It also may help replenish a Mississippi River that has at times been so low that barge traffic is halted so engineers can scrape the bottom to deepen it.
Forecasters predicted Isaac would intensify into a Category 1 hurricane by today with top sustained winds of between 74 and 95 mph. The center of its projected path took Isaac directly toward New Orleans today and Wednesday, but hurricane warnings extended across some 280 miles from Morgan City, La., to the Florida-Alabama state line. It could become the first hurricane to hit the Gulf Coast since 2008.
Evacuations were ordered for some low-lying areas, and across the region, people boarded up homes, stocked up on supplies and got ready for the storm. Schools, universities and businesses closed in many places.
Still, all the preparation may not matter if the great danger becomes flooding. In Pascagoula, Miss., Nannette Clark was supervising a work crew installing wood coverings over windows of her more than 130-year-old home. But she said all that won't matter if a storm surge reaches her home, as it did after Katrina in 2005.
"The water was up to the first landing of the stairs," she said. "So I get very nervous about it."
Isaac's approach coinciding with the Katrina anniversary invited obvious comparisons, but Isaac is nowhere near as powerful as Katrina was when it struck on Aug. 29, 2005. Katrina at one point reached Category 5 status with winds of over 157 mph. It made landfall as a Category 3 storm and created a huge storm surge.
Federal Emergency Management Agency officials said the updated levees around New Orleans are equipped to handle storms stronger than Isaac. Levee failures led to the catastrophic flooding in the area after Katrina.
"It's a much more robust system than what it was when Katrina came ashore," said FEMA Administrator Craig Fugate in a conference call with reporters.
In New Orleans, officials had no plans to order evacuations and instead told residents to hunker down and make do with the supplies they had.
"It's going to be all right," said New Orleans Mayor Mitch Landrieu.
Isaac could pack a watery double punch for the Gulf Coast. If it hits during high tide, Isaac could push floodwaters as deep as 12 feet onto shore in Louisiana, Mississippi and Alabama and up to 6 feet in the Florida Panhandle, while dumping up to 18 inches of rain over the region, the National Weather Service warned.
As of 5 p.m. EDT on Monday, Isaac remained a tropical storm but winds had gotten stronger at 70 mph. Its center was about 255 miles southeast of the mouth of the Mississippi River, and it was moving northwest at 12 mph.
The storm that left 24 dead in Haiti and the Dominican Republic blew past the Florida Keys with little damage and promised a soaking but little more for Tampa, where the planned Monday start of the Republican National Convention was pushed back a day in case Isaac passed closer to the bayside city.
Only a fraction of an expected 5,000 demonstrators turned out in Tampa to protest GOP economic and social policies outside the convention. Organizers blamed Isaac and a massive police presence for their weak showing.
The storm had lingering effects for much of Florida, including heavy rains and isolated flooding in Miami and points north. Gov. Rick Scott said that as of noon Monday, about 60,000 customers were without power in Florida as a result of the storm.
Scott, a Republican, was returning from the convention in Tampa to Tallahassee to monitor Isaac. Fellow Gulf Coast Republican Govs. Bobby Jindal of Louisiana and Robert Bentley of Alabama said they would not attend the convention at all. Mississippi Gov. Phil Bryant delayed his travel through Wednesday, leaving open the possibility he could attend the final day of the event.
States of emergency were in effect in Louisiana, Mississippi, Alabama and Florida.
The choppy ocean waters generated by Isaac weren't all bad for everyone, though. On Pensacola Bay, fishermen boasted big hauls.
"You get a little storm headed this way and they seem to run a little. When the barometric pressure drops, something causes them to run better," said Eric Roberts, who was out fishing for mullet.