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Bermuda High
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Dave Thurlow, Host
 
I'm Dave Thurlow from the Mount Washington Observatory and this is The Weather Notebook. Every summer, from Texas to Michigan, from Florida to Nova Scotia, at some point there is a prolonged period of hazy, hot and humid weather. The meteorological culprit for this is something called the Bermuda High.

A high, otherwise known as a high pressure area, is characterized by generally fair weather. One way to think of a high is as a sort of giant mound of air, one to two thousand miles across and about eight miles high. An important feature about this mound -- or we could call it something more technical -- a blob! - is that it rotates clockwise here in the northern hemisphere. This rotation means that the movement of air across the landscape underneath the high is around the center of the high, you know that big H you see on weather maps during those rare moments you aren't listening to radio. So, let's plop the center of one of these highs right over the island of Bermuda which is about 800 miles east of Charleston South Carolina. The clockwise rotation of the high will cause air to steadily stream northward from the gulf of Mexico, up across the southeastern part of the US and at times on to New England and beyond before curving eastward out into the Northern Atlantic. So air that may be in Portland Maine on one day, was in Virginia the day before and in the subtropics the day before that. The Bermuda High is one of the many meteorological mechanisms that moves heat away from the tropics, to places where it is not always welcome.

The Weather Notebook is produced by The Mount Washington Observatory in cooperation with New Hampshire Public Radio... funded by The National Science Foundation, and underwritten by Subaru -- the beauty of All-Wheel Drive.