A soaking rainstorm followed by plunging temperatures Monday led state officials to urge residents to keep travel to a minimum and use extreme caution on roads that will likely be dangerously icy this week.

“We want people to pay attention,” said Ted Talbot, spokesman for the Maine Department of Transportation. “These are going to be spotty freezes. (At) these low-lying intersections, valleys, bridges, everyone has to assume they’re ice-covered.”

Gov. Paul LePage issued a statement asking residents to avoid traveling, “both for your safety and the safety of highway crews working to clear the roads.”

On Monday, when the temperature reached a high of 50 degrees in Portland and nearly an inch of rain fell in the area, road crews rushed to clear culverts, drain standing water and treat roads before the cold made a comeback.

Forecasters expect temperatures in southern Maine to remain below freezing until Friday, said Mike Kistner, a meteorologist with the National Weather Service in Gray.

“You’ll probably be able to skate anywhere you want,” he said. “It’s going to be a mess.”

Statewide, about 375 Maine Department of Transportation trucks were out treating roads and clearing culverts that were inundated with debris and water from snowbanks that melted during the storm, Talbot said.

Meanwhile, the Penobscot Narrows Bridge near Bucksport, which was closed Sunday because of falling ice, was reopened Monday afternoon. Falling ice damaged or destroyed several passing cars on Dec. 29.

In Portland, crews cleared catch basins and began spreading a mixture of salt and sand on roads in the afternoon, although the expected overnight low of about 14 degrees renders road salt ineffective, said Portland Public Services Deputy Director Eric Labelle.

“When the temperatures come up, the salt will activate, but the sand on icy areas will give some friction,” Labelle said.

Portland got sporadic street flooding Monday, but nothing out of the ordinary for a warm, wet winter day, said Tim Nangle, spokesman for the Portland Fire Department.

Nangle advised homeowners with flat roofs to check whether their drainage systems are working properly. Snow left on a roof can get saturated with water, and if there are underlying structural problems, the weight can add to the risk of a roof collapse.

He also cautioned drivers to avoid standing water.

“If you can’t see the bottom of the water, don’t drive through it,” Nangle said.

Even the Maine Mall in South Portland sprang a few leaks in the rain Monday, said Stephanie Millette, a mall spokeswoman, but nothing out of the ordinary.

“During bad weather, leaks in our ceiling are relatively common,” Millette said. “They get fixed pretty quickly.”

Sporadic power outages hit several thousand households and businesses in Maine.

The weather service said wind gusts in Portland peaked at 37 mph around 12:15 p.m. Monday. A strong southerly wind blew warm air into the state for most of the day, with a westerly wind bringing cold air Monday night.

At one point, nearly 6,000 customers, mostly in Penobscot and Washington counties, were without power, said Emera Maine, formerly known as Bangor Hydro Electric Co. Only 446 customers were in the dark by 10:45 p.m.

Central Maine Power Co. had similar problems. At one point early Monday, 3,858 customers were without power. That number was down to 88 shortly before 11 p.m.

A dozen flights were canceled at the Portland International Jetport, and nearly as many were delayed, following a nationwide trend caused by winter weather. One in 10 flights nationwide were canceled Monday, according to The Associated Press.

Matt Byrne can be contacted at 791-6303 or at:mbyrne@pressherald.com