Goodbye to our January Thaw

Meteorologically it's a Singularity

It couldn't last forever. After a stretch of unseasonably mild January weather, winter is back. Today's storm threatens to dump up to 10 inches of snow in some areas of New England.

After temperatures soared to 60 degrees across Massachusetts on Saturday, permitting people to head outside with T-shirts.

But the mercury dipped on Sunday, and by Monday morning heavy snow was blanketing much of southern New England. West Brookfield, in central Massachusetts, had 7 inches by 10:30 a.m.

Logan closed, 2" in Providence  

Coastal areas from Cape Cod to Rhode Island saw a mix of snow, sleet and rain. Downtown Providence, R.I., got two inches before it turned over to rain.

Logan International Airport closed for 37 minutes during the morning, but soon reopened with two runways operating, Massport spokesman Phil Orlandella said. The average delay was more than two hours.See the WHDH video of this morning's commute here.

Expected accumulations are six-to-ten inches in the Springfield area, five-to-nine in Worcester and three-to-five in Boston.

Cape Cod is spared 

Cape Cod is expected to get mostly rain with the temperature getting almost to 50º at the elbow. As this was originally written at 7:30 a.m. the rain in the Orleans-Brewster area turns to sleet and back to rain with temperatures in the mid-thirties. By the 1 p.m. however the temperature in Chatham had risen to 42º and by sunset the Harwich temperature was 46º.

The snow may have caught some motorists off guard this morning, because a number of skidding accidents are reported on Bay State highways.

The photo above was the writer's driveway a year ago today showing illegal use of child labor. 

What IS a January Thaw

Stage Harbor LighthouseOur famous and hallowed January Thaw, which usually occurs during the third week of January across the area east of the Mississippi River and between 40 and 50 degrees North latitude, holds a special place in New England weather lore. It's as prominent as Autumn's Indian Summer around here and is unique to North America.

The January Thaw is defined in the Glossary of Meteorology published by the American Meteorological Society as "a period of mild weather, popularly supposed to recur each year in late January in New England and other parts of the northeastern United States.... Statistical tests show a high probability that it is a real singularity."

Singularity is a characteristic meteorological condition that tends to occur on or near a specific calendar date more frequently than chance would indicate.

Although there are no generally accepted weather parameters that specifically define it, to be a genuine January Thaw it is generally thought that it must last for several consecutive days and have maximum daily temperatures above freezing and mean daily temperatures around 10º above the expected mid-January normals. The John Fitts photo above shows what the lighthouse on Hardings Beach in Chatham looked like during last year's January un-Thaw this same week.

To see today weather details on the cape, click here

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