Ask the Weather Team
Vincent asks: I heard that this time of year the radar can see flocks of birds. Is this true?
Pete Bouchard says:
Not just now, but ANYTIME of year. Radar detects anything that is moving toward or away from the radar site. Sometimes it’s birds, sometimes it’s bees (if they’re in a swarm and very close to the site) and sometimes we can even see something as subtle as a sea breeze! Most often, however, we see military chaff (ordinance and debris) from pilots performing exercises offshore. When it’s apparent (and confirmed) we will most often show them on air.
Alan asks: We had a mild winter. What city does it compare to?
Pete Bouchard says: To make it simple, I used the meteorological winter (Dec. - Feb.) as a comparison. With an average temperature of 40° in December, 34° in January and 36° in February, Boston compares to typical winter in Salisbury, Maryland with it's average Dec.-Feb. temperatures of 39°, 35° and 37° respectively.
Quite a mild winter indeed!
Andree asks: Can it ever be too cold to snow?
Pete Bouchard says: Technically, no. Every airmass has a temperature and dewpoint, no matter how cold. If you cool the airmass down to the dewpoint, you have saturation and water vapor/ice crystals can form. Get enough moisture particles, and you can have precipitation.
Sometimes in cold climates, the temperatures will cool near the dewpoint and you can have miniscule snow crystals form. They're called diamond dust and they can happen with clear skies. While uncommon at our latitude, they are VERY common in Antarctica. Out of the 365 days in 1970, researchers found that 317 of them had diamond dust.
Victoria asks: In years past, how long into winter did we go without plowable snow?
Pete Bouchard says: Good question. And after the Halloween storm, we felt this might be our winter again, but both November and December have proved that wrong.
After a bit of research with other meteorologists at the National Weather Service in Taunton, we found the following:
Latest 2" snow was on Feb. 16, 1980
Latest 4" snow was on Mar. 3, 1915
Latest 6" snowstorm was on April 1, 1997. Which was also the date for the MONSTER nor'easter that clobbered us with snow over 22" of snow in Boston.
6th Grade UP Academy from South Boston asks: Why was it so warm in early October, and why was the sky so blue?
Pete Bouchard says: This has to do with a phenomenon we call subsidence.
There was a gigantic high pressure system "stacked" 30-45,000 feet up in the atmosphere. This high parked itself over the Northeast and Southeast Canada for a few days last Columbus Day weekend. In meteorology, high pressure systems are defined by their subsiding, or sinking, air. When air sinks, or drops from several thousand feet to the ground, it warms and spreads out in a clockwise direction around the center of the high.
This sinking, warming air provided the basis for our summerlike warmup, and the sun did the rest.
Subsidence also promotes clear skies. The more air you have moving downward, the less likely it is for clouds to form, since cloud formation requires rising air. That's why the skies were so blue and clear on the weekend of the 8th, 9th and part of the 10th.