Connecticut is expecting wind and rain heading into Christmas. But first, there will be a calm before the storm.

Western Connecticut State University Meteorologist Gary Lessor described the makings of an unusual winter storm.

On Thursday, Lessor said, the weather is supposed to be nice for the day. “If people have travel plans, there should be very little impact if any,” he said. “It will actually be a good day for traveling. It will be mostly cloudy, it will become breezier as the day progresses. In the morning we’re looking at winds that will be about 10 mph, but during the afternoon it’ll increase to 15-20 mph. There could be some morning sun.”

Thursday’s highs are going to be unseasonably mild, he said. A normal temperature range for this time of year is 40 degrees high and 26 degrees for a low, but on Thursday there is going to be a high of 55-60 degrees during the day. He said that could climb to the mid-60s Thursday evening, which should be generally dry with a couple scattered showers.

“The real action is going be late at night into midday on Christmas,” Lessor said. “We’re looking at very heavy rain, probably between 1.75 and 2.75 inches. Some places could go over 3. In addition, we’ll have the high wind — that’ll really begin to kick in after midnight. There’ll be sustained 25-35 mph gusts after midnight that could reach more than 60 mph.”

Heavy rain and high winds will persist until about midday, he said, with winds of 25-35 mph in the morning and then dramatically decreasing once the storm front rolls through. Temperatures also will drop once the front passes, but Christmas day should have 50-plus-degree weather for the better part of the afternoon.

“It will be unseasonably mild, giving everyone the opportunity to go for a walk, get outside and enjoy the fresh air,” Lessor said. “The good thing is we’re on the correct side of the storm. The upper Midwest and the upper plains, they’re on the cold side. They have basically blizzard conditions.”

The high temperatures and dewpoints in the Northeast could lead to flooding, as it could cause rapid snowmelt into rivers and streams, the National Weather Service warned. "Temperatures on Christmas morning will struggle to dip below the mid-40s across New England, potentially setting daily records," it said. 

Low temperatures behind the front could lead to widespread icy conditions, the service also warns.

Utilities preparing

Norwich Public Utilities notified customers Wednesday morning that NPU is preparing for the storm. Ahead of inclement weather, NPU inspects and fuels its field vehicles, makes sure there will be adequate staffing for water treatment plants, line and gas departments, the wastewater treatment facility, communications and other departments and tests its internal communications.

“In the event of widespread power outages related to the storm, NPU will provide regular updates on its Facebook page on its restoration efforts,” an email from NPU read. “NPU will also utilize its automated phone calling system if necessary to provide customers with information. NPU customers are strongly encouraged to prepare their homes and businesses for the possibility of power outages on Thursday evening and Friday.”

NPU recommended people keep abreast of the storm, stay back from downed wires, charge their electronics ahead of time, have flashlights ready, secure outdoor materials and have medication available or obtain another source of electricity if relying on medical equipment.

Eversource also was readying for the storm, telling customers it will preposition line and tree crews throughout the state. An email from the company stated that these crews will “respond to any damage or outages caused by this storm.”

“We recognize the last thing anyone wants is another storm, especially on Christmas. We’re taking all necessary actions now — including cancelling employee vacations and working to secure out-of-state crews — so our team is ready to respond to whatever this storm may bring,” said Craig Hallstrom, Eversource president of regional electric operations. “We’re pre-positioning crews and necessary equipment at our work centers throughout the state to respond to any damage to the electric system and restore power as quickly as possible so our customers can enjoy their holiday.”

Paul Mounds, chief of staff for Gov. Ned Lamont, said earlier Wednesday that the governor's office is in contact with United Illuminating and Eversource, and is closely watching the storm to see if any additional measures, such as activating the state's emergency operations center, need to be taken.

Day Staff Writer Julia Bergman contributed to this report.

s.spinella@theday.com