If you’ve taken a look at the forecast for the coming days across most of New England, you’ve probably noticed the mid-May sun won’t be shining at any point in the forseeable future.
There are several weather features that seem to have lost their gas pedal, and hence tend to linger in the atmosphere above aimlessly, seemingly without purpose or direction. One of these features is the culprit that will provide less-than-ideal weather conditions for the next several days, and is aptly referred to as a “cut-off” low by the meteorological world.
Low pressure systems that generally provide the more captivating weather scenarios tend to follow the main flow of the atmosphere, or the jet stream. The jet stream can be thought of as a river of air, tens of thousands of feet above the surface of the earth, that directs and dictates weather features that may exist throughout the miles of atmosphere beneath it. A day or two of windshield wipers, ominous skies, and swollen rivers will very often proceed and succeed a sustained period of more placid conditions-an oscillation that continues on through the seasons. This is the cycle that governs the weather patterns in a mid-latitude location such as this, and can be contributed to the focused flow that is the jet stream.
Every so often, though, a rift in this seemingly endless cycle disrupts the pattern meteorologists and weather enthusiasts alike have become familiar with, and throws a proverbial monkey wrench into the scenario. This rift occurs when a system inexplicably cuts off from the jet stream, and begins to meander about in the skies overhead. The cutting-off process happens as winds in the upper-levels of the atmosphere suddenly shift to a higher latitude, leaving a low pressure system that was originally part of the main flow behind, churning and dumping its rains with no place to go. Due to the now cut-off nature of this hypothetical system, there is no driving force behind it, and it can linger over an area for days, even up to a week, until the jet stream that left it in the dust to begin with drags a system through to oust the stubborn low. Cut-off lows very often give weather forecasters giant headaches, as they are notoriously difficult to predict, due in large part to the fact that computer models (a tool essential to any forecaster) find the listless lows quite perplexing.
With a cut-off low gallivating over the Tennesee Valley and throwing moisture northward into New England, an umbrella coupled with a light jacket look to be quite the essential commodity.