A storm that unleashed several inches of rain in heavy torrents Wednesday downed trees, caused minor flooding and cut off power to thousands across Kennebec County.

Mike Kistner, a meteorologist for the National Weather Service in Gray, said 4 to 6 inches of rain was expected in central Maine by the time the storm was over. Rain had tapered to a soft drizzle by late afternoon and was expected to clear the area by evening.

The weather service posted a flood warning for the region that was extended twice through 6:45 p.m. A flood watch remains in effect until 8 a.m. Thursday.

“We’ve had reports of flooding in several areas,” Kistner said.

The National Weather Service reported at 2:30 p.m. that nearly 6 inches of rain had fallen at the Portland International Jetport. Local totals had not been updated, but the service reported 5.5 inches had fallen in Vassalboro by 1:30 p.m.

Street Superintendent Jerry Dostie, of Augusta Public Works, said around 2 p.m. that the city had received more than 5 inches of rain.

“That’s essentially a 12- to 18-hour period, which is a lot of water,” Dostie said.

Several streets and parking lots flooded in Portland, Waterville and Skowhegan, while emergency responders and public works crews in the Augusta area reported only minor flooding. Union Street in Augusta was closed near the entrance to the Police Department, Dostie said, but most streets remained open with water covering parts of the street in different locations throughout the city.

“The biggest issue is the stormwater systems can only handle so much flow,” Dostie said. “What we’ve received in rain has exceeded that amount. It’s just a matter of time for the system to catch up.”

Construction crews on Mount Vernon Avenue were given the day off because of the rain. The road, while muddy in the construction zone, remained passable.

Firefighters in the southern areas of Kennebec County were called to deal with sporadic reports of trees and utility wires down. Downed wires were reported in Fayette, Mount Vernon, Monmouth and Manchester as well as elsewhere in the area, Winthrop police Chief Ryan Frost said.

The lower section of the dead-end Case Road in East Winthrop was closed for a couple of hours when a tree fell across the road, taking utility lines with it. Workers at the PALS animal shelter were unable to go home until the tree was cleared away a little before 4 p.m.

Central Maine Power Co.’s online outage reporting system reported 184 outages in Kennebec County as of noon, but that number jumped to more than 3,000 during the afternoon and stood at about 2,700 by early evening, when there were nearly 7,000 outages reported across the company’s coverage area in Maine.

Meanwhile, Winthrop Fire Chief Dan Brooks said the water was nearly cresting the road on Route 133 near Maranacook Lake. With the rain nearly stopped, Brooks expected the water to subside before covering the road. Crews were slowing traffic on Route 41, however, as a shallow stream crossed the road near the Maranacook Road intersection.

“It’s a little sketchy,” Brooks said. “It’s cleared out, but there’s an after-effect. Even though it’s stopped raining now, it’s still trying to get rid of the water that was there before.”

The rain slowed traffic and factored into at least one accident, in which a van drove into a ditch on Interstate 95 in Augusta just south of exit 112.

In Waterville, the Hannaford supermarket parking lot on Main Street filled with several inches of water, as did Front Street.

In Winslow, Cushman Road was closed to traffic early Wednesday afternoon as town public works crews cleared up trees that had fallen onto the road during the height of the storm.

Two downed trees were reported around 1 p.m. near 345 Cushman Road and came down across the street, blocking traffic. Drivers heading south on the road were turned around to find an alternate route.

Public works director Paul Fongemie, sitting in his pickup truck at the scene, said he wasn’t sure what caused the trees to come down.

According to Fongemie, one tree hit a pickup truck but did only minor damage. CMP did not report any power outages in Winslow.

At 2 p.m., Winslow Public Works also closed a section of China Road, Route 137, at the intersection with Augusta Road, U.S. Route 201, because of heavy flooding.

In Skowhegan, members of the Skowhegan Fire Department assisted in an inspection of the municipal building after rainwater leaked down a wall into the Police Department near the building’s computer server.

Route 43, which is Hartland Road between Athens and Hartland, was closed to all traffic about 2:30 p.m. Tuesday. Drivers were advised to take alternate routes for the rest of the afternoon.

In Skowhegan, a drainage pipe carrying a swollen brook under U.S. Route 201 clogged with debris, flooding the Skowhegan Plaza parking lot and creating sinkholes that threatened to gobble up a box carrier truck. The plaza, which houses five businesses, was evacuated.

By 4 p.m. the last of the vehicles in the lot had been moved or towed away, leaving only a Rent-A-Center truck standing by itself on top of pavement that looked as though it was collapsing into a sinkhole as the rushing waters of the brook — known locally as Creamery Brook — turned to whitewater rapids.

The stores in the plaza are New Garden Chinese Restaurant, Family Dollar, Rent-A-Center, Ginny’s health food store and the closed Bargain Hunter store. The New Balance Athletic Shoe factory annex on the river side of the parking lot was flooded as water rushed by and into the Kennebec River. Sandbags inside the building prevented serious flooding inside the building, workers said.

Police blocked off the plaza just as the traffic lights at the busy intersection that includes Main Street and West Front Street, which is a continuation of U.S. Route 2, stopped working, blocking traffic for as far as the eye could see.

Rick Curtis, manager of the Family Dollar store, said the water started flowing over the parking lot about 3 p.m.

“It started coming down into the parking lot. Then it started coming up out of the parking lot,” Curtis said. “That’s all going to go — the parking lot — I’m sure. The police came and evacuated all of us. There’s just so much water coming through.”

Water could be seen bubbling up through the pavement, quickly tearing up pieces of the asphalt. Firefighters went door to door in the plaza, making sure everyone was gone.

Earlier, Skowhegan Fire Department crews were sent just after 1 p.m. to the Municipal Building on Water Street because of a report of rainwater leaking down an interior wall in the area of the building’s computer server. Water seeped into the basement, where the Police Department is. No damage was reported. The Hannaford supermarket in Skowhegan was evacuated briefly after a fire alarm sounded. Trees and wires were down and roadways were flooded in dozens of locations in Somerset County as emergency and road crews scrambled to keep roads open.

In Hartland, emergency officials called for all available manpower as roads in that town flooded.

Morning Sentinel staff writers Peter McGuire and Doug Harlow contributed to this report.

Craig Crosby — 621-5642

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Twitter: @CraigCrosby4