These probabilities, expressed as percentages, indicate the chance of occurrence in 1998. This circulation system moves Atlantic waters northward from the vicinity of the Caribbean to an area east of Greenland. There, the current sinks to deep levels, moves southward and flows into the South Atlantic Ocean and beyond. Fahrenheit above the average North Atlantic sea surface temperature of about 45 F in the regions west of the British Isles - is associated with more intense hurricanes and more landfalls along the eastern seaboard, Gray said.
Cool water tends to dampen hurricane activity.
In general, the more hurricane activity you have, the greater the probability of landfall. Gray took hurricane activity for the past 98 years and calculated the ratio of the most active 33 years to the least active 33. The ratio was eight to one. He says that simple comparison, and the historical record, support his contention. You also have to take into account the Atlantic Ocean thermohaline circulation.