Hurricane Sandy Going West
Date: Fall 2012
have been following Hurricane Sandy for two reasons: it is my nickname and we are studying weather in school. We learned that storm systems in the middle latitudes always go west to east. This storm has been moving generally northward from its start north of Columbia and east of Panama, and since it crossed a latitude about 28 degrees north, it has been moving with some eastward motion, that is common to the storms we have studied. How is it that this storm is now moving from east to west as it has crossed 37 degrees latitude and it approaches the New Jersey shore? Also, most hurricanes are only about 250 miles across. This seems to be larger than 1000 miles. How can it expand like this over cooler ocean water?
Your curiosity has uncovered why Sandy was so devastating! There are at least three compounding energies at work here: a warm Hurricane, an Arctic Blast coming in mid USA and a boundary of Canadian cold water.
Hurricane Sandy was very warm, moving North with a counterclockwise rotation off the shore USA. A Southeasterly blast of cold air coming from Canada was moving counterclockwise in the mid US. The Canadian cold waters were still, but is quite a barrier.
As Sandy and the Arctic Blast collided, the warmer air rose and the twist drove the warm air North, but there is another cold boundary - Canadian waters. The colder air mass began to slide lower and under the warm/humid air then turn almost directly South. The result was that the cooler air dipped South and moved East, leaving Snow with all of the warmer/humid air from Sandy. Sandy was pinned by two layers of cold air. Sandy avoided the cold from Canada and the mid US by turning westward, the path of least resistance. Unfortunately, New Jersey was in the path of least resistance.
As the mid US Arctic Blast turns South, the path of least resistance will be almost due North. Sandy will probably move Northward and lose energy quickly.
Category 1 Hurricanes tend to be less organized than Hurricanes having higher energy, which is why Sandy was quite expansive.
Hope Illinois avoided most of it! We sure got it here! Peter E. Hughes, Ph.D, Milford, NH
The reason it turned west is a high pressure area to Sandy's north. The high stops the hurricane from going east and is called a blocking high.
Hope this helps.
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Update: November 2011