Lucas' Weather Discussions

This past week saw quite the windstorm unfold over the northeastern quadrant of the contiguous US, stretching from Minnesota to Kentucky to Maine. Most places affected saw wind gusts topping 50 mph, more than enough to cause scattered power outages, with some reaching 60 mph. These gusty northwesterly winds are not all that uncommon in the wintertime, as blizzards do form and produce this kind of destructive wind patterns. That said, most areas didn’t experience a prototypical blizzard, with the exception of Wisconsin and Minnesota.

So if this wasn’t a blizzard, then how did it get so windy?

First, we must have an idea of what causes the wind. Generally speaking, it is the flow of air from regions of high pressure to regions of low pressure, and the closer (and stronger) the regions are to one another, the stronger the pressure gradient between them. It is this pressure gradient that results in a force enacted on the air in and near the systems, called the pressure gradient force (PGF). For all intents and purposes, it is this force that drives the wind we feel at the surface.

To visualize the PGF on a map, one must look at a plot of sea level pressure (above) and look for the strongest gradients that don’t involve mountainous regions (the Rocky Mountains always seem to have a really strong pressure gradient, this is because elevation causes problems with this parameter), denoted by bunches of isobars (lines between colors here) packed really close together. This can be seen over Minnesota and Wisconsin, stretching into the Ohio Valley.

This area of strong PGF moved eastward, impacting much of the northeast and New England, causing strong wind gusts in the area, some topping 60 mph. This pales in comparison to the peak wind observation atop Mount Washington, a place prone to extreme wind, where they measured a gust to 171 mph on Monday. This was the highest recorded wind speed in their history in the month of February. For perspective, the highest wind gust measured at the summit was during a storm in 1934, where they measured 231 mph. So yes, they are used to crazy wind up there at 6,288 feet.