Hurricane Philippe (2011)

Hurricane Philippe is the 17th named storm and 5th hurricane of the above-average 2011 Atlantic hurricane season. It formed on September 24, 2011 as Tropical Depression Seventeen south west of the Cape Verde Islands. Since Philippe remained away from land, no deaths or damage was reported. Lasting over 13 days, it is the longest lived Atlantic tropical cyclone since Bertha in 2008.

Meteorological History
On September 23, a well-defined tropical wave emerged off the coast of Africa, associated with plentiful shower and thunderstorm activity. Moving westward and embedded within a favorable environment for development, the wave quickly became organized. During the morning hours of September 24, the National Hurricane Center designated the low as a tropical depression, while located about 290 mi (465 km) south of the southernmost Cape Verde Islands. Later that day, the depression was upgraded to a tropical storm, designated "Philippe". Since that time strong shear from both upper level winds and later on from Ophelia's outflow, as well as periodic entrainment of dry air kept the cyclone both small and disorganized, with the center often exposed to the point where the low level circulation reformed under the convection that defines a tropical system at least once. An exposed cyclone can be seen as a wispy series of clouds circling a small area, rather than under the canopy of thunderstorms. Because of this hostile environment, Philippe remained near the minimum for a tropical storm. On the afternoon of October 2, an Advanced Scatterometer (ASCAT) pass confirmed that Philippe was a strong tropical storm, contrary to satellite estimates. Despite high wind shear, it remained a strong tropical storm afterward and actually at times developed an eye feature. On October 6, after over 12 days as a tropical storm, Philippe became a Category 1 hurricane.