Storm history of Hurricane Wilma

The **meteorological history of Hurricane Wilma**, the strongest tropical cyclone known in the Western Hemisphere, began in the second week of October 2005. A big weather system formed across much of the Caribbean Sea and slowly organized to the southeast of Jamaica. By late on October 15, the system was became strong for the National Hurricane Center to name it Tropical Depression Twenty-Four.

The depression slowly moved southwestward, and in conditions that were good for strengthening, it strengthened into Tropical Storm *Wilma* on October 17. In the beginning, development was slow because of its large size, although thunderstorms slowly organized. From October 18, and over the next day, Wilma underwent explosive deepening over the open waters of the Caribbean; in a 30-hour period, the system's central atmospheric pressure dropped from 982&nbsp;mbar (29.00&nbsp;inHg) to the record-low value of 882&nbsp;mbar (26.05&nbsp;inHg), while the winds increased to 185&nbsp;mph (300&nbsp;km/h). At its strongest, the pinhole eye of Wilma was about 3&nbsp;miles (5&nbsp;km) in diameter, the smallest known eye in an Atlantic hurricane. After the inner eye died off because of an eyewall replacement cycle, Wilma weakened to Category 4 status, and on October 21, it made landfall on Cozumel and on the Mexican mainland with winds of about 150&nbsp;mph (240&nbsp;km/h).

Wilma weakened over the Yucatán Peninsula, and reached the southern Gulf of Mexico before speeding up northeastward. Despite increasing amounts of wind shear, the hurricane re-strengthened to hit Cape Romano, Florida as a major hurricane. Wilma weakened as it quickly crossed the state, and entered the Atlantic Ocean near Jupiter, Florida. The hurricane again re-intensified before cold air and wind shear penetrated the inner core of convection. On October 26, it turned into an extratropical cyclone, and the next day, the remnants of Wilma were absorbed by another extratropical storm over Atlantic Canada.

## Formation
The origin of Hurricane Wilma is complicated. During the second week of October, an unusually large, monsoon-like lower-level circulation and a large area of disturbed weather developed over much of the Caribbean Sea. The system was enhanced by diffluence—the rate at which a fluid moves—from an upper-level low across the southwestern Atlantic. By October 13, a broad area of low pressure developed and persisted about 150&nbsp;miles (240&nbsp;km) southeast of Jamaica, possibly aided by the passage of tropical waves through the area at the time.

Later on October 14, the system became much better organized, with increasingly organized shower and thunderstorm activity, as conditions in the upper levels of the atmosphere became significantly more favourable. It was then that the National Hurricane Center first said that it was possible for a tropical depression to develop in the area. Dvorak classifications were initiated on October 15. By late on October 15, the surface circulation became defined well-enough, with enough organized deep convection, for the National Hurricane Center to designate the system as *Tropical Depression Twenty-Four* while it was about 220&nbsp;miles (345&nbsp;km) east-southeast of Grand Cayman.

As Tropical Depression Twenty-Four drifted southwestward, it steadily organized; by early on October 16, rainbands began to slowly consolidate with well-established outflow, and a large upper-level anticyclone developed over the depression. Although deep convection and banding features increased, mid-level dry air from the north prevented significant organization, and the convection was split into two primary areas. Surface buoy reports indicated that, due to its large size, the system failed to strengthen beyond tropical depression status, even though it received tropical storm strength Dvorak classifications from The National Hurricane Center's Tropical Analysis and Forecast Branch and the National Oceanic and Atmospheric Administration's Satellite Analysis Branch. Continued reconnaissance flights reported peak winds of about 30&nbsp;mph (50&nbsp;km/h).

## Peak strength
By early on October 17, the outer rainbands, which had previously controlled the structure of the cyclone, dissipated, while deep convection developed near and to the south of the center. Computer models predicted steady strengthening as the depression moved westward before turning to the north.  Deep convection continued to develop to the south of the center, and the depression strengthened into Tropical Storm Wilma at 0600&nbsp;UTC on October 17, while about 200&nbsp;miles (320&nbsp;km) southeast of Grand Cayman. Right after becoming a tropical storm, the National Hurricane Center predicted Wilma to track west-northwestward, reaching winds of 105&nbsp;mph (170&nbsp;km/h) before striking the northeastern portion of the Yucatán Peninsula. The storm continued to the southwest while deep convection laid near the center. Late on October 17, a Hurricane Hunters flight into Wilma recorded winds of 50&nbsp;mph (80&nbsp;km/h), but an unusually low pressure of 989&nbsp;mbar (29.21&nbsp;inHg), which would be more typical of a minimal hurricane. This was because of a number of unusual low pressures across the region, which resulted in a lesser pressure gradient and thus lighter winds. Convection continued to develop near the center and became much more symmetrical.

Tropical Storm Wilma began to turn to the west-northwest on October 18, At 1200&nbsp;UTC on October 18, Wilma strengthened into a Category 1 hurricane while about 225&nbsp;miles (360&nbsp;km) south-southeast of Grand Cayman.

Early on October 19, Wilma attained major hurricane status while continuing to rapidly intensify, and by 0600 UTC, the storm's maximum sustained winds increased to 170&nbsp;mph (275&nbsp;km/h), making Wilma a dangerous Category 5 hurricane on the Saffir-Simpson Hurricane Scale. At the time of its peak intensity, hurricane-force winds extended only 50 miles (85&nbsp;km) from the small center of Wilma, with tropical storm force winds extending only about 160&nbsp;miles (260&nbsp;km).

## First landfall
Shortly after peaking in intensity, the coldest cloud tops surrounding the eye warmed a little bit and an outer eyewall began to form, meaning that an eyewall replacement cycle was happening. Early on October 20 the hurricane weakened to Category 4 status after the small, inner eye dissipated and the 45&nbsp;mile wide outer eyewall became the new eye. and Wilma retained the large eyewall as it turned northwestward. with one forecast predicting it to make landfall on the Yucatán Peninsula with winds of 165&nbsp;mph (265&nbsp;km/h), though Wilma remained a strong Category 4 hurricane as it tracked northwestward. At about 2145&nbsp;UTC on October 21, Wilma made landfall on the island of Cozumel with winds of 150&nbsp;mph (240&nbsp;km/h). It weakened a little bit as it continued northwestward, and struck the Mexican mainland near Puerto Morelos at 0330 UTC on October 22, with winds of 135&nbsp;mph (215&nbsp;km/h)

## Second landfall and demise
On October 22, the mid-level ridge to the north of Wilma later dissipated, leaving the hurricane moving northward across the northeastern Yucatán Peninsula. About 26&nbsp;hours after making landfall on Cozumel, Wilma emerged into the southern Gulf of Mexico near Cabo Catoche with winds of about 100&nbsp;mph (160&nbsp;km/h). After reaching open waters, Reconnaissance Aircraft reported the remains of an inner eyewall and an outer eyewall measuring between 70 and 90&nbsp;miles (110 to 145&nbsp;km) in diameter. Convection deepened around the eyewalls, and the inner core of convection, which had previously become disrupted over land, became a little bit more organized.

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A powerful eastward-moving mid-level trough across the central United States turned the hurricane northeastward and caused it to gradually speed up. Vertical wind shear increased as strong upper-level southwesterly flow increased, though in spite of the shear Wilma continued to intensify. Despite wind shear values of about 30&nbsp;mph (48&nbsp;km/h), Wilma strengthened further to reach winds of 125&nbsp;mph (200&nbsp;km/h). It weakened a little bit as it approached Florida, and made landfall at Cape Romano with winds of 120&nbsp;mph (195&nbsp;km/h) at around 1030&nbsp;UTC on October 24. Early on October 25, the hurricane reached a secondary peak intensity of 125&nbsp;mph while about 340&nbsp;miles (545&nbsp;km) east of Jacksonville, Florida. Shortly thereafter, the wind shear combined with its rapid forward motion of 50&nbsp;mph (80&nbsp;km/h) resulted in a slow weakening trend. By 1170&nbsp;UTC on October 25, the center was to the northwest of the primary convection as cold air from the southwest disturbed the circulation. The remaining convection continued to diminish, and early on October 26 Wilma turned into an extratropical cyclone while about 230&nbsp;miles (370&nbsp;km) southeast of Halifax, Nova Scotia. The extratropical remnant continued east-northeast before being absorbed by another extratropical storm on October 27.

## Related pages
* Hurricane Wilma
* 2005 Atlantic hurricane season

## References
## Other websites
* Tropical Cyclone Report  on Hurricane Wilma.
* The NHC's archive on Hurricane Wilma.