Temperature Extremes

Meteorologist Todd Gutner calls out low temperatures on Tuesday morning’s broadcast of News Center Maine.
Photo: News Center Maine
By Lee Burnett
The coldest air of the year descended on Sanford earlier this week, and Sue Tholen knew what was in store as she drove from her home in Kennebunk to Sanford Seacoast Regional Airport, where she works as a part-time flight instructor.
“It dropped five degrees between Kennebunk and Sanford,” she said in a telephone interview. “When it’s extra cold, I can almost guarantee it’s going to be colder at Sanford airport.”
Sure enough, the temperature at the airport bottomed out at minus 17 degrees Tuesday morning. It was the coldest overnight temperature in the region. It was 19 below Wednesday morning, though Fryeburg and Caribou were colder.
Temperature extremes – both hot and cold – are a known thing at Sanford’s airport, where automated weather data collection instruments gather and send a variety of data to the National Weather Service and others. Among forecasters, Sanford is known as a “Death Valley of the East,” according to Todd Gutner, meteorologist at News Center Maine.
“I didn’t coin the term. That was [retired meteorologist] Joe Cupo,” said Gutner with a laugh. He said it also applies to Fryeburg in Oxford County.
The temperature extremes are caused by terrestrial factors, Gutner said.
“It’s the topography, to be honest,” he said. “The Mousam is not a large river, but it creates sort of a valley. On cold winter nights when it’s calm and clear, cold air is heavier, and it will pool in that bowl.”
Something else happens on hot summer days, he said. Sinking air moving downslope increases atmospheric pressure and heats up. “On southwest or westerly winds when you’re not getting any ocean influence, those sea breezes, you’re going to cook,” he said.
Conditions at the airport are ripe for radiational cooling, said National Weather Service meteorologist Greg Cornwell. Sanford is far enough from the moderating influence of the ocean and sits in a bit of valley with Bauneg Beg Mountain to the west. The elevation is 240 feet above sea level. “On cold nights, little to no wind and no cloud cover, you get radiational cooling. The surface loses its heat very rapidly.” said Cornwell. Fresh snow enhances cooling as well, he said. “Fryeburg airport is another cold spot. Sanford is certainly a standout for York County.”
The weather oddities at the airport are not limited to temperature, says Tholen, who works for Southern Maine Aviation. “The weather is a little different here. If there’s fog, it’s the first to go clear or the last to go clear,” she said. “I swear, we are unique.”
The cold changes operating procedures for small planes at the airport, she said. Below 40 degrees, engine heating pads are plugged in several hours before take-off, as starting a cold engine can damage it from different expansions of metal parts. Below 20 degrees, no “touch and go” maneuvers are allowed. On cold days, the engine deceleration of landing subjects a hot engine to a “shock cooling” that can damage the engine, she said. Below zero degrees, no flying is allowed.
“We’re trying to be on the safe side,” she said.
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