In March or April of every season, we begin thinking about what our strategy for hurricane season (roughly from June to November) will be. In 2014 and 2015, we secured and left Elizabeth Jean respectively in a hurricane hole, or south of the hurricane zone. Rather than stay with Elizabeth Jean through the tropical summer our first two years out, we flew north.
Our strategy this season, in contrast, was to sail to more temperate areas north of the most intense hurricane zone. Hurricanes, however, can stray north as Hurricane Sandy demonstrated in 2012. Therefore, part of our daily weather briefing includes information on potential tropical systems as they form off Africa’s coast. There the differences between the hot, dry Sahara Desert in north Africa and the cooler, wetter, and forested coastal environment in west Africa form the African Easterly Jet, a band of strong high altitude winds. The Jet is unstable and undulates in a north-south direction, often forming a north to south trough, or wave, that moves westward off the West African Coast. When these waves of air have enough moisture, lift, and instability, they form thunderstorms, sometimes becoming correlated with a center of air circulation. This circulation may form a tropical cyclone as the areas of disturbed weather move westward across the Atlantic.
For more about hurricane formation see http://response.restoration.noaa.gov/about/media/what-does-sahara-desert-have-do-hurricanes.html
Hurricane Hermine dominated our weather watch for the latter part of August. On August 18, the National Hurricane Center designated the system while still off Africa as an Investigative Area (or an Invest for short) and given a number. In ten days, the system had crossed the Atlantic and had become a Tropical Depression (TD). Named Hermine on August 31, she became a hurricane a day later and reached land on September 2. After first landfall, the system moved north along the Atlantic Coast. We didn’t start moving south from Maine until September 6.
We are now keeping a close eye on Hurricane Matthew, which began off Africa’s coast as Invest 97L.