Weather: At Least There’s SunshineBy Robert Lindsay Korty
STAFF METEOROLOGIST -- January is often a dark, cold month in Boston. The days are short, and if a series of storms track up the East Coast, it can be quite a gloomy month. Last winter was quite mild, with the mean temperature in January 7°F (4°C) higher than normal. There is no arguing that this year January has been cold. This week the first real outbreak of Arctic air has spread across the northern United States. High temperatures will not crack freezing at any point in the coming days.
At least there is a plethora of sunshine to keep these cold days bright. The amount of water that an airmass can hold is an exponential function of temperature. Warm air is capable of holding far more moisture than is cold air. (though, of course, this by no means ensures that it will: compare a typical 90°F (32°C) day in Phoenix with one in Miami) Very roughly, the amount of water vapor that an airmass is capable of holding doubles with every 10°C (18°F) rise in temperature. For this reason, Arctic airmasses, which are exceedingly cold, are also quite dry. Only occasional, light snow flurries will pass over New England this week. A more substantial storm, over the Rocky mountains today, will bring snow to parts of the Southeast U.S. before passing offshore Thursday evening.
Today: Occasional clouds and cold. High 22°F (-6°C).
Tonight: Partly cloudy and cold. Low 14°F (-10°C).
Thursday: Mostly sunny and cold. High 20°F (-7°C).
Thursday night: Cloudy with flurries possible. Low 17°F (-8°C).
Friday: Becoming sunny and remaining cold. High 25°F (-4°C); low 13°F (-11°C).