People around south Louisiana kept a wary eye on Hurricane Isidore's progress on Sunday as emergency preparedness officials discussed the possibility the storm could hit the state Gulf coast.

Officials with 12 south Louisiana parishes participated in a conference call with National Weather Service forecasters, looking for clues about where the storm would head next.

Residents checked in regularly with parish officials and watched broadcast reports as forecasters discussed the chance Isidore could move toward the Louisiana coast.

"People are monitoring it, they're concerned about it. But it's not the entire talk of the town," said Aaron Ertel, senior coordinator with the St. Charles Parish Department of Emergency Preparedness.

By nightfall, the Category 3 storm was over the northern Yucatan Peninsula, where it shredded trees, twirled streetlights and forced tens of thousands to flee their homes about 20 miles east of Merida, Mexico, the National Hurricane Center said.

The storm had sustained winds of 120 mph, and a slow, west-southwestward motion is expected through late Monday; on that track, the storm's center would remain over the northwest Yucatan at least through early Monday, the Hurricane Center said.

Forecasters said the storm was expected to emerge into the Gulf. Within two days, it was likely to start veering toward the northwest or north, in the direction of Louisiana or Texas.

Some parish officials were startled to hear that forecasters are all but certain that Isidore will make a northward turn toward Louisiana.

"There was no if, and or but. They are definitely talking about the turn," said Walter Maestri, Jefferson Parish's emergency preparedness director.

Tim Coulon, Jefferson Parish president, stressed that the storm is still a long way off, and said residents should not panic. The forecasters told officials that the storm could hit anywhere from Brownsville, Texas, to Biloxi, Mississippi.

"We've gotten many phone calls. Nobody knows where it's going, so they're looking to us for instructions," said Christina Gallusser, a spokeswoman with the Calcasieu Parish emergency preparedness office.