Spring comes, then goes again
WINCHESTER — Today, it becomes official.
At 12:37 p.m., the sun will appear to move across the equator of Earth, ushering in spring.
Most residents of the Valley have seen robins and a few bluebirds, have crocus and daffodils pushing up in their gardens and realize that their dogs and cats are starting to shed all over the rug.
So they won’t be surprised.
Amy Bettwy, meteorologist with the National Weather Service office in Sterling, is even offering sunshine and a warming trend to the mid- and upper 50s through Saturday.
Then, it all ends — again.
“A strong cold front will push through the area Saturday night,” said Bettwy, as has happened several times during March.
While she isn’t forecasting any precipitation, temperatures on Sunday, Monday and Tuesday are expected to drop back into the 40s.
The “vernal equinox,” which marks the start of improving weather, fresh flowers and the anticipation of ripe tomatoes, is a Latin term meaning green and equal night.
It is the calendar point when day and night are supposed to be roughly equal in length, as the seasons move from winter’s short days and long nights to summer’s direct opposite.
The hours of daylight and darkness aren’t exact, because Earth’s gravity can bend light, which means we can “see” the sun before it actually rises above the eastern horizon and even after it has actually set below the west.
Of course, those terms aren’t exactly accurate, since the sun is static in the sky and Earth rotates toward and away from it.
Because of a tilt in its axis from north pole to south, the Earth tends to lean its northern point toward the sun during our summer season, and away from the sun during winter.
That brings more hours of daylight across the northern section (above the equator) in summer, and less in winter — resulting in the four seasons.
This winter has been fairly severe in the Mid-Atlantic area and into New England.
Some people were hoping that was bad news for a particular pest, the brown marmorated stink bug.
The insect, an alien invader from Asia, has become a major threat to a wide variety of vegetables and fruits on the East Coast.
Chris Bergh, entomologist with the Alson H. Smith Jr. Agricultural Research and Extension Center on Laurel Grove Road in Frederick County, squelched that thought Wednesday.
Scientists studying the bugs here and in Kearneystown, W.Va., haven’t seen any unusual die-off, he said.
“In some locales, yes, there is winter kill,” Berg said. “In other places, they look just fine. It’s a function of where they are.”
Bergh said one of his colleagues put stink bugs in a Styrofoam container and left them outside in a bucket during the cold weather. A substantial number died, he said. “But that doesn’t translate into bugs over-wintering in their natural habitat.”
Stink bug numbers are usually down in the spring, he added. But enough will emerge in April and May to breed and begin a new cycle in June.
Those young nymphs will be adults in August and ready to breed themselves.
Bergh noted that the only year when stink bug numbers drastically declined was in early 2013, after Superstorm Sandy swept through the area on Oct. 29, 2012. However, they did rebound.
“We’ve only had three years to study these things,” Bergh added. “In the big picture, that’s not very long.”
Looking ahead to better times, Bettwy offered a glimpse into the future weatherwise.
The forecast models, she said, refuse to predict either above or below normal levels of either temperature or precipitation for the next 90 days.
That could mean something like “normal” weather ahead, whatever that means.
— Contact Val Van Meter at email@example.com