On August 25, a tropical wave entered the Atlantic ocean. It produced some thunderstorm activity over the next several days as it crossed the tropical Atlantic, but was struggling enough with wind shear and dry air that it didn't manage to organize through the end of the month. The wave turned west-northwestward as it approached the northeastern-most Caribbean islands on September 1. Conditions were still only marginally favorable, but the system managed to develop into Tropical Storm Earl late on September 2.
Around that time, Earl was making its closest approach to the Leeward Islands. Most of the gale force winds were displaced to the north and east of the center, so the islands only recieved scattered downpours from the passing tropical storm. The center of circulation outran the deep convection a little the next day, a sign of continuing wind shear. On the 3rd, the storm passed north of the Virgin Islands and strengthened modestly, but remained fairly disorganized.
The steering currents in the atmosphere around Earl were not very strong. Though the storm was gradually turning north toward a break in the low-level ridge to its north, it did so only very slowly, so occasional heavy rain persisted for a while in the northeast Caribbean, particularly Puerto Rico. The storm was still sheared, but the direction of shear changed by late on September 4 to more closely align with the storm's motion. That pattern is a little more conducive for strengthening, so the resilient Earl continued its slow intensification. The cyclone took on a comma shape, with a long tail of thunderstorms extending south and west of the core. It at last made some progress away from the islands on September 5 and very deep convection began to blossom near the center of circulation.
By the 6th, the storm was moving due north at a sluggish pace. It underwent some more structural change, with hints of an eyewall developing. Earl wasn't the most symmetric storm on satellite, but it managed a remarkable feat of continually strengthening in spite of shear and became a hurricane that day.
The wind shear began a slow decline at last on September 7, allowing the hurricane to gain strength a little more quickly, since it remained over warm water with an ample supply of moisture. That evening, Earl became a category 2. Hurricane hunter aircraft sampling winds in the system over the next day found lower maximum winds than otherwise might have been expected given Earl's appearance on satellite. As a result, the intensity was adjusted down to category 1. However, the storm's central pressure was relatively low, which was consistent with the observed large radius of tropical storm force and hurricane force winds. Earl only expanded further as it gained latitude.
The cyclone made its closest approach to Bermuda from the southeast in the early morning hours of September 9, bringing gale conditions. By that time, the storm was moving north-northeast.
Despite some disruptions to its circulation, Earl made another comeback later that day, regaining category 2 status and reaching its peak intensity of 105 mph winds and a pressure of 954 mb. The storm also briefly had a large eye. It wasn't long though before extratropical transition began, since Earl was encountering colder water off the coast of Atlantic Canada. Before becoming post-tropical, the storm ballooned to a huge size, with an estimated diameter of tropical storm force winds of over 750 miles. At last, the cyclone became post-tropical on September 10. What was left of Earl slowed down and meandered east of Newfoundland for the next several days as it steadily weakened.
The above image shows Earl on September 10 before extatropical transition. Nova Scotia and Newfoundland are visible at top left.
Earl's track was standard fare for a Cape Verde hurricane, but it did reach peak intensity unusually far north.
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