Hartford – Gov. Dannel P. Malloy said this morning that officials are greatly concerned about the likelihood of large-scale flooding in communities along the Long Island Sound - particularly the western shore - as Hurricane Irene swirls toward an early Sunday landfall.

Voluntary evacuations are underway in shoreline communities from Greenwich to East Haven. The governor said he pleads with residents who live near rivers and streams and low-lying areas to evacuate now while they still can. Forecasters are expecting tides that would be 1 to 2-feet higher than those of "The Perfect Storm" that hit Connecticut in the early 1990s, he said.

"If you're near a river or near a stream or on Long Island Sound, particularly western Long Island Sound, what are you doing home right now?" Malloy said during a news briefing from the Emergency Operations Center in the state Armory.

Earlier this morning President Obama declared a state of emergency in Connecticut, authorizing federal aid to supplement state and local hurricane response efforts. Emergency assistance will be provided at 75 percent federal funding.

Malloy, in his request for the emergency designation, estimated pre-landfall hurricane costs at $1.9 million.

The governor has announced a roadway ban for all non-emergency vehicles that will take effect soon after midnight tonight. He urged people to finish errands and be off the roads by nightfall.

At least 200 Connecticut National Guard troops will be on duty for clean-up operations Sunday. An additional 500 guardsmen will be on duty by Monday. Officials with the Federal Emergency Management Agency have been working in Connecticut since Friday, Malloy said.

Additional evacuation zones may be announced later today.

"You can always hope that the things that we fear don't happen, but we have to prepare for the things that we fear," the governor said.