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2005 Atlantic hurricane season

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This map shows the tracks of all tropical cyclones in the 2005 Atlantic hurricane season . The points show the location of each storm at 6-hour intervals. The colour represents the storm's maximum sus
MarioProtIV · Public domain

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Through Mississippi and Atmospheric pressure

The four Category 5 hurricanes during the season were Emily, Katrina, Rita, and Wilma. In July, Emily reached peak intensity in the Caribbean Sea, becoming the first Category 5 hurricane of the season, later weakening and striking Mexico twice. It was the first Category 5 hurricane recorded in the month of July and was the earliest-forming Category 5 hurricane on record, until Hurricane Beryl surpassed the record in July 2024. In August, Katrina reached peak winds in the Gulf of Mexico but weakened by the time it struck the U.S. states of Louisiana and Mississippi. The most devastating effects of the season were felt on the Gulf Coast of the United States, where Katrina's storm surge crippled New Orleans, Louisiana, for weeks and devastated the Mississippi coastline. Katrina became the costliest U.S. hurricane, leaving $125 billion in damage and 1,392 deaths. Rita followed in September, reaching peak intensity in the Gulf of Mexico before weakening and hitting near the border of Texas and Louisiana. The season's strongest hurricane, Wilma, became the most intense Atlantic hurricane on record, as measured by barometric pressure. Lasting for ten days in October, Wilma moved over Cozumel, the Yucatán Peninsula, and Florida, causing over $22 billion in damage and 52 deaths.

The season's impact was widespread and catastrophic. Its storms caused an estimated 3,468 deaths and approximately $171.7 billion in damage. It was the costliest season on record at the time, until its record was surpassed 12 years later. It also produced the second-highest accumulated cyclone energy (ACE) in the Atlantic basin, only behind the 1933 season. The season officially began on June 1, 2005, and the first storm, Arlene, developed on June 8. Hurricane Dennis in July inflicted heavy damage to Cuba. Hurricane Stan in October was part of a broader weather system that killed 1,673 people and caused $3.96 billion in damage to eastern Mexico and Central America, with Guatemala hit the hardest. The final storm, Zeta, formed in late December and lasted until January 6, 2006, the latest of any season, tied with 1954.

Seasonal forecasts

Ahead of the formal start of the season, various groups issued forecasts for the number of named storms, hurricanes, and major hurricanes in the upcoming season, including Colorado State University (CSU), the Cuban Institute of Meteorology (InsMet), Tropical Storm Risk (TSR), and the United States National Oceanic and Atmospheric Administration (NOAA). Some forecasts predicted how many tropical cyclones would affect a particular country or territory.

Pre-season forecasts

The first of these forecasts was issued by CSU, which predicted on December 5, 2004 that the season would be above average and feature 11 named storms, 6 hurricanes and 3 intense hurricanes. They also noted that the Caribbean and the entire United States coastline faced an increased risk of a major hurricane making landfall. TSR issued its first forecast a few days later and predicted that the season would feature 9.6 tropical storms, 5.7 hurricanes, 3.3 major hurricanes, and predicted that the accumulated cyclone energy (ACE) rating would be 145.

During January 2005, TSR increased its forecast to 13.9 tropical storms, 7.8 hurricanes, 3.6 major hurricanes, and predicted that the ACE rating would be 157. CSU issued its first updated forecast on April 1, increasing their prediction to 13 tropical storms, 7 hurricanes, and 3 major hurricanes, with a continued risk of a major hurricane landfall in the Caribbean or United States. The increase was based on the Atlantic continuing to warm and a strong belief that El Niño conditions would not persist into the hurricane season. On May 2, the Cuban Institute of Meteorology (InsMet) issued their seasonal forecast, which predicted that the season would feature 13 tropical storms and 7 hurricanes. This was followed on May 16 by NOAA, who predicted a 70% chance of above normal activity, with 12–15 tropical storms, 7–9 hurricanes, and 3–5 major hurricanes. The agency cited favorable conditions associated with an active phase of the Atlantic multidecadal oscillation (AMO). CSU issued its second forecast update on May 31, revising its forecast to 15 named storms, 8 hurricanes and 4 major hurricanes; by this point, the group believed El Niño conditions were unlikely.

Midseason outlooks

In their July forecast update, TSR anticipated that the season would be exceptionally active and well above average; the group increased their forecast to 15.3 tropical storms, 8.8 hurricanes, and 4.1 major hurricanes, with an ACE rating of 190. By the end of July, seven tropical storms and two major hurricanes had developed within the basin, which prompted CSU, InsMet, NOAA and TSR to significantly increase their seasonal forecasts at the start of August. In their August 5 update, CSU predicted that 13 more storms would form, with seven more hurricanes and three more major hurricanes. At the start of September, CSU updated their forecasts and predicted that eight more storms would form, with six more hurricanes and three major hurricanes. By the end of September, 17 named storms had developed, of which nine had developed into hurricanes and four had become major hurricanes. Within their final update for the year, CSU predicted that October would feature three named storms, two hurricanes and one major hurricane.

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