While we usually associate tornadoes with the Great Plains and Southeast, as we observed yesterday, they can occur in any region of the lower 48 States. Coming on the heels of tragic storms in Missouri and Alabama, the deadly tornadoes in Massachusetts seemed to suggest a doomsday scenario but their occurrence was merely a reflection of the typical weather patterns that produce such storms.
For the past few days, a dome of hot, humid air dominated the eastern U.S., from the Gulf of Mexico to New England; this atmospheric ridge was the product of an active, late spring jet stream, which dipped through the West and then looped northward across the Great Lakes and southern New England. To its north, Canadian high pressure was dropping southward, producing a clash zone across Massachusetts that was further energized by the turbulent jet stream. As typically occurs, severe thunderstorms ignited when the cold air undercut the hot, humid air and intersecting winds(the westerly jet and strong, southerly surface winds) produced rotation within these storms, spawning the deadly tornadoes.
When tornadic storms sweep across the vast plains, destroying barns and uprooting trees, we pay little attention to their power. Unfortunately, we have witnessed a series of direct hits on urban centers, raising our awareness of their destructive force and leading to the false assumption that a major change has occurred in our planet's atmosphere. Once again, our brief life spans and the relatively short period of recorded weather history produce this false conclusion and will lead some to blame these tragic events on global warming or divine intervention.
