Which Way is the Storm Going to Go? Background Information
A hurricane is a vortex ~ circular in shape with winds flowing around its center.
In the center dry air is sinking, but there is no wind. It has a calm center (the eye).
It is similar to a spinning top.
The hurricane is steered by global winds ~ the wind currents from the surface to 50,000 feet.
Click here to link to NOAA page that explains how global winds are created.
As Atlantic Ocean hurricanes travel westward in the tropical easterlies they often get swept into the prevailing westerly winds and seem to curve to the northeast. This is because of a high pressure dome near Bermuda, known as the Bermuda High. The clockwise rotation of air in the Bermuda High is often the driving force that sweeps the hurricane into the prevailing westerly wind band.
Below is the track of Hurricane Wilma ~ you can see how it travels west and then "curves" to the northeast.