LITTLE ROCK — Tropical Storm Isaac arrived in Arkansas on Thursday with hail and tree-toppling winds, a precursor to a forecast of flooding as the storm sloshes across the state.

Meteorologist John Robinson of the National Weather Service in Little Rock said he expected the rainfall to intensify after dark Thursday, because tropical systems tend to contract at night and produce greater rainfall.

Gov. Mike Beebe said emergency crews were ready to move, but none had been summoned as of mid-afternoon.

"We’ve got everybody on standby. State police is on standby. Obviously the National Guard is. All of our emergency responders or people who would be expected to help in a weather event like this are on standby and prepared," Beebe said.

About 2 inches to 5 inches of rain was forecast for most of Arkansas, though some areas could get significantly more, Robinson said. Winds were between 15 mph and 25 mph, with occasional gusts of close to 50 mph.

Even though Isaac was downgraded to a tropical depression just before 4 p.m. Thursday, forecasters said residents needed to remain aware that tornadoes can develop quickly in supercells — too rapidly for warnings to be issued.

The greatest tornado threat was in the southeast corner of the state, which had already seen wind gusts of 40 mph or more blow down trees in Chicot County and knock out power in the small farming town of Eudora.

About 13,000 customers lost power as scattered outages popped up across the southern half of the state. Pea-sized hail fell at Holley Mountain Airpark near Clinton in central Arkansas.

The storm’s center was forecast to move into western Arkansas later Thursday, bringing a greater danger of flash floods as rainfall courses down the Ouachita and Ozark mountains. A flash flood watch is in effect through Friday.

Beebe said the state is ready to open shelters if they are needed.

In eastern Arkansas’ flat Delta farmland, farmers raced to bring in rice, corn and soybeans ahead of the storm. Growers were particularly concerned about corn and rice, which can’t be properly harvested if it’s blown to the ground.

Matt Winsand, manager of Cain AGRA in Lake Village in Chicot County said he stayed open until 1 a.m. Thursday while farmers unloaded soybeans.

"With $17 (per acre) soybeans, it’s important to get them in the elevator as soon as possible," Winsand said.

Beebe said he’s concerned about farmers taking another financial hit after enduring a summer-long drought.

"I worry about the wind for eastern Arkansas for the row crops. I worry about the water for the people," Beebe said.

Many in the state, after listening to warnings about Isaac for the past week, were looking ahead to the storm’s exit.

Organizers of the Hot Springs Blues Festival said the show would go on as scheduled downtown on Friday and Saturday, and the University of Arkansas plans to play its football opener as scheduled in Fayetteville on Saturday. As of mid-afternoon Thursday, schools and businesses hadn’t announced closings for Friday.

The state Department of Parks and Tourism reported that many Labor Day weekend reservations were canceled at state parks and privately owned hotels, mainly by Louisiana residents who decided against vacationing.

Tourism officials remained optimistic that the weekend would bring good weather. But the state first has to get past the threat of flooding, which has been deadly in the past.

In June 2010, a sudden flood during a nighttime thunderstorm along the Little Missouri River in southwest Arkansas killed 20 people, including seven children, at the Albert Pike Campground. Campers weren’t warned, and the water tumbled over RVs and even pulled up concrete pads on which they were parked.

Officials are advising motorists to not drive on roadways covered with water, as cars can be washed away in flash floods.