Hurricane Sandy's Transformation
Right now Hurricane Sandy is almost exactly one day from landfall on New Jersey...
Hurricanes and tropical storms derive their energy from the warmth and moisture of warm oceans, and Sandy is no exception. Such tropical storms are warm-core systems, with the warmest air in their centers. In general, tropical storms are not found in regions with large horizontal changes in temperature.
Recently, there has been a substantial warm anomaly of the sea surface temperature (SST) of the western Atlantic (SST much warmer than normal), which helps tropical systems like Sandy move northward and stay strong longer than normal. Here is a recent map showing the SST anomaly: much warmer than normal along the path of Sandy, by over 1.5C! So a very attractive welcome mat had been laid for tropical storms over the western Atlantic