What’s in a Nor’easter?

Changing gears from my earlier post, how about some clarification about those folks down east.  You know, those people in the north.  No, not up there to the south.  That’s the direction the wind is blowing, you know, northerly.  Of course in a Nor’easter they blow the other way, towards the southwest, hence the name.  That’s right, a storm that blew in from the west, combined with the Gulf Stream coming from the south and sent down that cold air from the northeast. Confused?

To those who are meteorologically challenged, some clarification might be helpful.  If you understood the prior paragraph, feel free to move on down the trail.  Otherwise, here goes.

Generally, when the weather person says there is a northerly or north wind, that does not mean that the wind is blowing you to the north, even though it may sound like it.  Rather, a north wind is coming from the north and will blow you to the south.

Much of the rest of that first paragraph uses colloquialisms from the northeastern United States, especially the New England coast.  First, you have to think like a sailor.  Okay, get your mind out of the gutter.  And no cursing like a sailor either.  Just pretend you are on a sailboat, like those colonizing, genocidal Brits who settled the north Atlantic coast of the United States.  For them, the wind direction was the most important factor in navigation.  Next, you need to know that a boat sailing downwind is moving in the same direction as the wind, or “with the wind”.  A boat moving upwind is moving in the opposite direction of the wind, or “against the wind”.

With that in mind, the terms become clearer.  The prevailing wind direction on the northeastern coast is southwesterly.  In other words, the wind comes from the southwest and blows towards the northeast.  So, Boston is downwind from New York and Portland, Maine is downwind of Boston.  That coastline runs generally in a northeast-southwest direction, although many people tend to think of it as north-south coastline.  In fact, many portions of that coast are fairly east-west, such as the Maine coast and the coasts of Connecticut and Long Island.  So, for a nautically-minded lad or lass, Portland is “down east” of Boston, i.e. it is downwind and to the east.  Similarly, someone in Portland might talk about going “up” to Boston.

And as far as that Nor’easter, it is actually a circular storm system whereby winds bring down cold air from the north, moving southward along the coast.  It is like a tropical cyclone, or hurricane, except that its energy comes from cold air rather than warm air.  So, even though the original storm system comes from the west, and the Gulf Stream brings wind from the southwest along the coast, a low pressure area forms and allows the wind to loop back around, providing that counterintuitive northeasterly wind.

Published in: on March 2, 2009 at 18:13  Comments Off on What’s in a Nor’easter?  
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