Hurricane Isidore was the ninth named storm and fourth hurricane of the 1990 Atlantic hurricane season. Isidore was a Cape Verde hurricane, developing in the far eastern Atlantic Ocean well south of the Cape Verde Islands on September 4. Isidore rapidly attained hurricane status, and ultimately became absorbed by an extratropical in the northern Atlantic Ocean on September 17.
Isidore caused no damage and no deaths.
|Formation||September 4, 1990|
|Dissipation||September 17, 1990|
|Highest winds||100 mph|
|Lowest pressure||978 mbar|
|Part of the||1990 Atlantic hurricane season|
Isidore developed from a vigorous tropical wave that exited the coast of Africa on September 3. Due to the time of the year as well as the location, it appeared for a while that Isidore was going to be a typical Cape Verde hurricane. However, due to a persistent mid-level trough in the central Atlantic Ocean, Isidore moved north-northwest and away from land. On September 4, the first Dvorak classifications began on the wave when METEOSAT satellite imagery indicated that the wave was accompanied by a large and well-defined low-level cyclonic circulation with associated deep convection. By 0000 UTC September 5, the wave was designated as Tropical Depression Ten and by 1200 UTC that same day, the depression became a tropical storm. Isidore began to rapidly intensify, and it became a hurricane near 0000 UTC September 7. That morning, Isidore reached its peak intensity of 100 mph. As Isidore head north-northwest, it encountered strong vertical wind shear in association with the aforementioned mid-level trough that was inducing the northward component of motion. At 1800 UTC September 8, Isidore weakened to a tropical storm. However, this was short-lived, as an upper-level low developed along the trough and broke off from of it, moved southward, and provided some ventilation for Isidore, which enhanced its upper-level outflow and lessened the shear over the storm. Isidore regained hurricane status after 24 hours as an eye appeared on satellite imagery. On September 17, Isidore was absorbed by a large extratropical cyclone north of 50°N.
Lack of Retirement
Because it did not affect land, the name Isidore was not retired in the Spring of 1991 by the World Meteorological Organization. It was used again in 1996 and also during 2002. It was retired following the 2002 season, being replaced with Ike for the 2014 Atlantic hurricane season.