Hurricane Karen was the eleventh named storm and fourth hurricane of the 2007 Atlantic hurricane season. Karen formed in the central Atlantic Ocean on September 25 from a vigorous tropical wave. Karen moved west-northwest, and, like Ingrid before it, dissipated just days later due to strong vertical shear caused by an unseasonably strong upper-tropospheric trough. Karen dissipated on September 29, having affected no land areas.
Karen caused no damage and no deaths.
|Formation||September 24, 2007|
|Dissipation||September 29, 2007|
|Highest winds||75 mph|
|Lowest pressure||988 mbar|
|Part of the||2007 Atlantic hurricane season|
On September 21, a tropical wave left the coast of Africa, accompanied by only a few showers and thunderstorms, but with a large area of low pressure at low latitudes. The wave moved westward across the Atlantic Ocean and over the next couple of days, convection associated with the wave increased, and the broad low-level circulation with the wave gradually became better defined. Banding features soon developed, and early on September 23, the first Dvorak classifications were taken on the wave. During this time, the wave was located about 550 miles south of the Cape Verde Islands. The wave continued west-northwest with no appreciable change in organization until late on September 24, at which time banding features became organized. By 0000 UTC September 25, the wave organized enough to be designated Tropical Depression Twelve while located about 720 miles west-southwest of the Cape Verde Islands. The depression intensified into Tropical Storm Karen just six hours later. For about a day after Karen's formation, there was only a slight increase in organization and strength. However, early on September 26, Karen's cloud pattern became much better organized, and the cyclone strengthened significantly, becoming a hurricane by around 1200 UTC September 26. Later that day, a strong upper-level trough to the west of the hurricane produced strong southwesterly vertical shear over the circulation. As a result, Karen quickly weakened, and weakened to a tropical storm by 0000 UTC September 27. Later that same day, the circulation center became exposed to the west and southwest of the deep convection. Karen continued to gradually weaken due to the unrelenting shear and by September 28, it was only a minimal tropical storm. During this time, the storm's forward motion changed from west-northwest to north, possibly due to changes within the center's involvement with the deep convection or a temporary surge of low-level southerlies. Some minor convective flareups occured near the center, but did not persist due to the strong vertical shear. Early on September 29, Karen had degenerated into a tropical depression, and it began to move westward in the low-level flow.
After 1200 UTC that same day, Karen's circulation became extremely disorganized, and a well-defined center could no longer be tracked. Karen's remnants meandered in the vicinity of the Leeward Islands as an area of squalls for the next few days.
Lack of Retirement
Because the storm remained away from land, it caused no damage and was thus not retired by the World Meteorological Organization in the Spring of 2008. It is on the list of names to be used for the 2013 Atlantic hurricane season.