Storm history of Hurricane Katrina

The **storm** **history of Hurricane Katrina** started on August 23, 2005. Hurricane Katrina was a highly destructive Category 5 hurricane which formed as Tropical Depression Twelve near the Bahamas. The next day, the tropical depression strengthened to a tropical storm, and was named *Katrina*. Katrina continued on to make landfall on the southern part of the U.S. state of Florida as a Category 1 hurricane.

While passing across Florida, Katrina weakened to a tropical storm. However, the warm waters of the Gulf of Mexico allowed it to rapidly intensify to the sixth strongest Atlantic hurricane in recorded history. Afterwards, Katrina made landfall as a Category 3 hurricane near Buras-Triumph, Louisiana, and once more near the Mississippi/Louisiana border. Katrina did not stop going northward through the central United States and finally dissipated near the Great Lakes, where it was absorbed by a cold front.

## Formation
Tropical Depression Twelve formed over the southeastern Bahamas at 5:00 p.m. EDT (2100 UTC) on August 23, 2005. Some of the tropical depression was from the remains of Tropical Depression Ten, which had dissipated from the effects of a nearby upper tropospheric trough. 

## First landfall
As the atmospheric conditions surrounding Tropical Depression Twelve were good for tropical development, the system began to strengthen, was upgraded to Tropical Storm status and given the name *Katrina* on the morning of August 24. A burst of convection allowed Katrina to become the fifth hurricane of the 2005 season on August 25, only two hours before it made landfall around 6:30 p.m. EST (2230 UTC) between Hallandale Beach and Aventura, Florida.

Katrina struck the peninsula at a high speed with 80&nbsp;mph (130&nbsp;km/h) winds, and had a well-defined eye on Doppler weather radar, which stayed undisturbed throughout its passage over Florida. The storm weakened over land on August 26 to a tropical storm, but regained its strength as a hurricane at 2:00 a.m. EDT (0600 UTC), about one hour after making landfall in Florida. Parts of the Florida Keys experienced tropical storm force winds throughout August 26, with the Dry Tortugas briefly experiencing hurricane-force winds.

## Gulf of Mexico
Katrina continued a westerly and west-southwesterly track, which forecast Katrina to move westward into New Orleans.

Right after the storm entered the Gulf of Mexico, the low wind shear, good upper-level outflow, and the warm sea surface temperatures of the Gulf Loop Current caused Katrina to intensify rapidly. On August 27, the storm was upgraded to Category 3 strength, becoming the third major hurricane of the season. An eyewall replacement cycle inhibited strengthening of its maximum winds for about 18 hours, but nearly doubled the size of the storm as a result. It became a Category 5 storm by 7:00 a.m. CDT, twelve hours after the beginning of the second round of rapid intensification, and reached its peak intensity at 1:00 p.m. CDT with maximum sustained winds of 175&nbsp;mph (280&nbsp;km/h), gusts of 215&nbsp;mph (344&nbsp;km/h) and a central pressure of 902&nbsp;mbar (26.64&nbsp;inHg). The minimum pressure made Katrina, at the time, the fourth most intense Atlantic hurricane on record.

Overnight on August 29, and into the morning of the next day, Katrina quickly weakened (in terms of maximum sustained winds) as it began to enter another eyewall replacement cycle. The inner eyewall disappeared before an outer eyewall had fully formed, which was one of the reasons of its rapid weakening. In 18&nbsp;hours, the hurricane's maximum sustained winds decreased from 170&nbsp;mph (280&nbsp;km/h) to 125&nbsp;mph (205&nbsp;km/h). One half of the storm continued to race northward, affecting the Central United States, and it was last noticeable in the eastern Great Lakes region. On August 31, it was absorbed by a frontal boundary and became a powerful extratropical low, causing 1.97–6.69&nbsp;inches (50–170&nbsp;mm) of rain in 12 hours. It also caused gale-force wind gusts from 31 to 61&nbsp;mph (50 to 98&nbsp;km/h) in southeastern Quebec and northern New Brunswick. In the region of Saguenay and Côte-Nord, rain caused breakdowns and failure in roads. The Côte-Nord region was isolated from the rest of Quebec for at least 1 week. However, the other half of Katrina broke off in the eastern part of the Appalachians, which caused a major tornado outbreak in the area from central Georgia to central Pennsylvania. The tornadoes were strong, killing two people and creating heavy damage.

## Related pages
* Hurricane Katrina
* Hurricane Katrina tornado outbreak
* National Weather Service bulletin for New Orleans region

## References
## Other website 
* National Hurricane Center's Tropical Cyclone Report on Hurricane Katrina
* National Hurricane Center's archive on Hurricane Katrina
* Hydrometeorological Prediction Center's archive on Hurricane Katrina
* Hurricane Katrina Rainfall Information from HPC