As though freed from a winter of self-isolation, Arctic air has been roaring into the region consistently during the last several weeks. And that’s a major reason it has been extraordinarily windy around here, said Jonathan O’Brien, a meteorologist at the National Weather Service Office in Mount Holly.
In fact, for sustained winds, last month officially was the windiest April in 24 years with an average sustained wind of 11.6 mph, with gusts of 25 mph or higher on 20 different days.
That trend has spilled into May, with 25-mph-plus gusts on six of the first nine days. On Saturday 37-mph gusts were recorded officially at Philadelphia International Airport.
“It’s been an unusual stretch,” said O’Brien.
The Arctic intrusions have been imported by exceptionally strong areas of high pressure, or heavier air, moving in behind a sequence of potent storms with their lower pressure, or lighter air. Highs and lows work in tandem, with the heavier air pouring in to the lighter.
The greater the pressure gradient, or difference, the stronger the breezes.
“It’s been pretty windy across the East,” said Alan Reppert, a meteorologist with AccuWeather Inc.
A popular metaphor to describe the effect of pressure differences is that of air escaping from a punctured tire. The air inside the tire might weigh about 35 pounds per square inch; the air outside about 14.8 pounds. Around here lately, it’s felt like living among about a trillion punctured tires.
The trees know all about it.
“We have been keeping busy in these strange times,” said Jason K. Parker, district manager of the Davey Tree Expert Co., in Horsham, Montgomery County. Those sudden bursts of wind “are often more damaging” to trees than the sustained winds associated with longer-duration storms, he said.
On average, April is one of the windier months of the year as summer attempts to nose northward into grounds that winter is often reluctant to surrender.
Those of us who live in the midlatitudes frequently endure the collateral damage in the form of severe storms and damaging winds.
This year, however, the battle overhead evidently has been especially ferocious.
The winds are forecast to back off some Sunday evening, but gusts in the vicinity of 25 mph are due to return Monday and Tuesday.