Another Nor’ Easter…What is a Nor’ Easter anyway?

November 5th, 2012 at 9:39 am by under Weather

Classic set up for a Nor’ Easter

When many people hear about this storm they think the name is because of it’s geographical region. While it’s true that it does effect the east coast and in particular the northeastern east coast it really is not named a Nor’ Easter because of it’s location. As far as the name many people ask why did the ‘th’ get dropped from the end? Conjecture is that the Boston based sailors in their dialect pronounced it that way and it just came to be.

The Nor’ Easter begins off the coast of Virginia usually and it gets energy from the Gulf Stream of the Atlantic. Even though the Atlantic is a very cold ocean basin The Gulf Stream is a narrow portion of water that flows almost all the way around the world. In fact, the Gulf Stream is given credit for making the weather more moderate in the United Kingdom. Otherwise, we’d probably be looking at a much more Nordic pattern with much colder temperatures.

Getting back to the Nor’ Easter and the Gulf Stream. The Gulf Stream adds energy to the low pressure and more importantly moisture which then moves around the low and slams into arctic air which is sitting across the northeast and then there is heavy snow.

A Nor’ Easter

If the storm moves up the east coast it is known as “on shore forming” this formation usually brings rain/freezing rain and some light snow.

If the storm stays off the coast it is know as “off shore forming” and that’s when the coastal cities like Boston and Maryland get heavy snowfall. Many times these storms become blizzards as sustained winds reach up to 35 mph and stay that way for more than 3 hours. This was the set up for the blizzard of 1978 which was also a huge storm for the east coast.

The 1981 “perfect storm” actually joined with another land based cyclone and caused record damage the upper northeast. When “Sandy” struck the coast it was very similar to the “perfect storm”. But “Sandy” had a central pressure that was actually lower than the 1981 perfect storm which made it a stronger and more potent storm with stronger winds. The other component that “Sandy” had was a high tide. Since tides respond to astronomical functions the tides were “high” when “Sandy” struck because of the full moon at the time. This took storm surges to record levels for this storm. This pressure was the highest of any storm north of the Carolinas.

What’s Happening This week?

This week from the European Forecast Model and another Nor’ Easter.

This model represents a snap shot of where the storm will be on Thursday morning about 1am. The European was the best model in predicting ‘Sandy’s’ path. It’s counter part which is called the GFS is taking the storm off the coast and could be a snow storm at that point. This model is bringing it on on shore from the coast for an “off shore forming’ low pattern which would bring mostly rain and possible freezing rain. The biggest problem with this storm that I see are the winds to an area that has already been ravaged by a record strong storm.

 

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