(Updated 10:38 p.m) Gov. Dannel P. Malloy is considering closing roads to all non-emergency vehicles during the height of Hurricane Irene, which was moving slowly up the East Coast toward Connecticut on Saturday after making landfall in North Carolina.

PHOTOS & VIDEO: Inside the Eye of Irene

Irene, which has the potential to be the most powerful tropical storm to hit Connecticut in more than 20 years, weakened a bit before arriving in North Carolina with sustained winds of 80 mph, down from 115 mph recorded earlier. The storm measures about 500 miles across and already is dumping rain all over the Eastern seaboard.

If it becomes necessary to close roads, Malloy said, the ban will go into effect as early as midnight and could include the tree-lined Merritt and Wilbur Cross parkways.

At this point we are prepared to close roads, Malloy said Saturday evening during his last media briefing of the day.

“We are particularly mindful of the Merritt Parkway and the Wilbur Cross,” and as such have pre-stationed apparatus to close those roads, ” Malloy said. “We’re loathe to close it before we have to, but I would think by about 12 o’clock tonight we’re talking about closure.”

Malloy said the midnight deadline wasn’t a hard deadline but an estimate based on the current weather patterns, which just got a little more complicated with another separate system pushing from the western part of the state as the hurricane pushes north. Malloy said at the point where the two systems meet there will be strong winds, as strong as hurricane winds as Irene departs.

Malloy suspended public transit buses and Shore Line East rail services as of 8 p.m. on Friday. MetroNorth travel was suspended at noon on Saturday. During his last briefing of the day Malloy said the last two flights will land at Bradley International Airport at 10 p.m. and 12 a.m. before it closes.

Malloy said he didn’t want to close the Merritt and Wilbur Cross — which are among the state’s busiest roads— while they are still passable. He said he will be making the call when and if it becomes necessary.

Meanwhile, Americans from North Carolina to Maine were scrambling to either get out of the storm’s way, or they were instead buying every loaf of bread, jug of water, or portable generator they could find. By Friday afternoon, most retailers were sold out of just about anything that could be considered an emergency supply item.

President Barack Obama signed a pre-landfall emergency declaration for Connecticut on Saturday morning, authorizing the Department of Homeland Security and Federal Emergency Management Agency to coordinate disaster relief efforts. The declaration also makes the state eligible for federal funds and assistance before the storm’s arrival.

Malloy also activated the National Guard, notifying 500 soldiers and airmen to report for storm duty this weekend. The number of active National Guard members could increase to 700 by Monday.

Portions of the Connecticut shoreline already are being evacuated, including sections of Old Saybrook, Branford, Bridgeport, and 25 others. Seventeen municipalities have declared a state of emergency.

According to tidal schedules, the next four high tides will arrive in Old Saybrook at 9:57 p.m. Saturday, 10:20 a.m. and 10:40 p.m. on Sunday, and at 11:05 a.m. and 11:26 p.m. on Monday. Officials said a storm surge coupled with a regular high tide can be particularly dangerous.

Officials are concerned about both the storm surge — which is a higher than usual tide brought about by low barometric pressure and wind — as well as flooding along the state’s waterways because of heavy rain. Forecasters say Hurricane Irene is packing a lot more rain — between 8 and 10 inches — than Hurricane Gloria in 1985, which dumped relatively little rain on Connecticut for a major storm.

“If you live in an area that has experienced flooding in the past, you need to remove yourself,” Malloy said. “And we are requesting you remove yourself, and please understand, once this storm hits with its full force, we’re going to be unable to help you.”

Branford Police warned residents of the Thimble Islands to evacuate on Friday.

But invariably there’s always someone who wants to stay, Branford Capt. Geoffrey Morgan told the Branford Eagle.

However, evacuating shoreline areas isn’t the only concern for officials.

“We’re concerned about the legnth of the time this storm will be in the state and what that will mean to trees that are unusually heavy because we’ve had a lot of rain this summer,” Malloy said.

Connecticut Light and Power said it has 800 contractor line and tree crews ready to respond as soon as it’s safe to do so.

“During the height of the storm, we will not have our crews out in the field.  Their safety is as important to us as the safety of the public we serve,” Jeff Butler, CL&P president and chief operating officer, said.  “Once conditions allow, we will begin responding to 911 calls to de-energize downed wires and make the area safe. At the same time, we will work with town public works crews to clear roads for emergency vehicles and begin restoring power to our customers.”