The 2012 Atlantic hurricane season was the final year in a string of three consecutive very active seasons since 2010, with 19 tropical storms. The 2012 season was also a costly one in terms of property damage, mostly due to Hurricane Sandy. The season officially began on June 1 and ended on November 30, dates that conventionally delimit the period during each year in which most tropical cyclones form in the Atlantic Ocean. However, Alberto, the first named system of the year, developed on May 19 – the earliest date of formation since Subtropical Storm Andrea in 2007. A second tropical cyclone, Beryl, developed later that month. This was the first occurrence of two pre-season named storms in the Atlantic basin since 1951. It moved ashore in North Florida on May 29 with winds of , making it the strongest pre-season storm to make landfall in the Atlantic basin. This season marked the first time since 2009 where no tropical cyclones formed in July. Another record was set by Hurricane Nadine later in the season; the system became the fourth-longest-lived tropical cyclone ever recorded in the Atlantic, with a total duration of 22.25 days. The final storm to form, Tony, dissipated on October 25, and the season came to a close when Hurricane Sandy became extratropical on October 29.
Pre-season forecasts by the Colorado State University (CSU) called for a below average season, with 10 named storms, 4 hurricanes, and 2 major hurricanes. The National Oceanic and Atmospheric Administration (NOAA) issued its first outlook on May 24, predicting a total of 9–15 named storms, 4–8 hurricanes, and 1–3 major hurricanes; both agencies noted the possibility of an El Niño, which limits tropical cyclone activity. Following two pre-season storms, the CSU updated their forecast to 13 named storms, 5 hurricanes, and 2 major hurricanes, while the NOAA upped their forecast numbers to 12–17 named storms, 5–8 hurricanes, and 2–3 major hurricanes on August 9. Despite this, activity far surpassed the predictions.
Impact during the 2012 season was widespread and significant. In mid-May, Beryl moved ashore the coastline of Florida, causing 3 deaths. In late June and early August, Tropical Storm Debby and Hurricane Ernesto caused at least eight and twelve deaths after striking Florida and the Yucatán, respectively. In mid-August, the remnants of Tropical Storm Helene killed two people after making landfall in Mexico. At least 41 deaths and $3.07 billion (2012 USD) were attributed to Hurricane Isaac, which struck Louisiana on two separate occasions in late August. However, by far the costliest, deadliest and most notable cyclone of the season was Hurricane Sandy, which formed on October 22. After striking Cuba at Category 3 intensity on the Saffir–Simpson hurricane wind scale, the hurricane moved ashore the southern coastline of New Jersey. Sandy left at least 235 dead and $68.7 billion worth of damage in its wake. At the time, Sandy was the second-costliest U.S. hurricane on record, behind Hurricane Katrina in 2005. Collectively, the season's storms caused at least 304 fatalities and about $72.3 billion in damage, making 2012 the deadliest season since 2008 and the costliest since 2005.
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Seasonal forecasts +Predictions of tropical activity in the 2012 seasonSourceDateNamedstormsHurricanesMajorhurricanesRefAverage (1981–2010) 12.1 6.4 2.7 Record high activity30157†Record low activity10†0†TSRDecember 7, 20111473WSIDecember 21, 20111273CSUApril 4, 20121042TSRApril 12, 20121363TWCApril 24, 20121162TSRMay 23, 20121363UKMOMay 24, 201210*N/AN/ANOAAMay 24, 20129–154–81–3 FSU COAPSMay 30, 2012137N/ACSUJune 1, 20121352TSRJune 6, 20121463NOAAAugust 9, 201212–175–82–3Actual activity 19102* June–November only: 17 storms observed in this period.† Most recent of several such occurrences. (See all) In advance of, and during, each hurricane season, several forecasts of hurricane activity are issued by national meteorological services, scientific agencies, and noted hurricane experts. These include forecasters from the United States NOAA's National Hurricane and Climate Prediction Center's, Philip J. Klotzbach, William M. Gray and their associates at CSU, Tropical Storm Risk, and the United Kingdom's Met Office. The forecasts include weekly and monthly changes in significant factors that help determine the number of tropical storms, hurricanes, and major hurricanes within a particular year. As stated by NOAA and CSU, an average Atlantic hurricane season between 1981 and 2010 contained roughly 12 tropical storms, 6 hurricanes, 3 major hurricanes, and an accumulated cyclone energy (ACE) Index of 66–103 units. NOAA typically categorizes a season as either above-average, average, or below-average based on the cumulative ACE Index; however, the number of tropical storms, hurricanes, and major hurricanes within a hurricane season is considered occasionally as well.
Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. Therefore, storms that have a long duration, as well as particularly strong hurricanes, will have high values of ACE. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of . Accordingly, tropical depressions are not included here. After the storm has dissipated, typically after the end of the season, the NHC reexamines the data, and produces a final report on each storm. These revisions can lead to a revised ACE total either upward or downward compared to the operational value. Until the final reports are issued, ACEs are, therefore, provisional.
Pre-season forecasts On December 7, 2011, Tropical Storm Risk (TSR), a public consortium consisting of experts on insurance, risk management, and seasonal climate forecasting at University College London, issued an extended-range forecast predicting an above-average hurricane season. In its report, TSR noted that tropical cyclone activity could be about 49% above the 1950–2010 average, with 14.1 (±4.2) tropical storms, 6.7 (±3.0) hurricanes, and 3.3 (±1.6) major hurricanes anticipated, and a cumulative ACE index of 117 (±58). Later that month on December 21, Weather Services International (WSI) issued an extended-range forecast predicting a near average hurricane season. In its forecast, WSI noted that a cooler North Atlantic Oscillation not seen in a decade, combined with weakening La Niña, would result in a near-average season with 12 named storms, 7 hurricanes, and 3 major hurricanes. They also predicted a near-average probability of a hurricane landfall, with a slightly elevated chance on the Gulf Coast of the United States and a slightly reduced chance along the East Coast of the United States. On April 4, 2012, Colorado State University (CSU) issued their updated forecast for the season, calling for a below-normal season due to an increased chance for the development of an El Niño during the season. In April 2012, TSR issued their update forecast for the season, slightly revising down their predictions as well.
On May 24, 2012, NOAA released their forecast for the season, predicting a near-normal season, with nine to fifteen named storms, four to eight hurricanes, and one to three major hurricanes. NOAA based its forecast on higher wind shear, cooler temperatures in the Main Development Region of the Eastern Atlantic, and the continuance of the "high activity" era – known as the Atlantic multidecadal oscillation warm phase – which began in 1995. Gerry Bell, lead seasonal forecaster at NOAA's Climate Prediction Center, added the main uncertainty in the outlook was how much below or above the 2012 season would be, and whether the high end of the predicted range is reached dependent on whether El Niño develops or stays in its current Neutral phase. That same day, the United Kingdom Met Office (UKMO) issued a forecast of a below-average season. They predicted 10 named storms with a 70% chance that the number would be between 7 and 13. However, they do not issue forecasts on the number of hurricanes and major hurricanes. They also predicted an ACE index of 90 with a 70% chance that the index would be in the range 28 to 152. On May 30, 2012, the Florida State University for Ocean-Atmospheric Prediction Studies (FSU COAPS) issued its annual Atlantic hurricane season forecast. The organization predicted 13 named storms, including 7 hurricanes, and an ACE index of 122.
Mid-season outlooks On June 1, Klotzbach's team issued their updated forecast for the 2012 season, predicting thirteen named storms and five hurricanes, of which two of those five would further intensify into major hurricanes. The university stated that there was a high amount of uncertainty concerning whether or not an El Niño would develop in time to hinder tropical development in the Atlantic basin. They also stated there was a lower than average chance of a major hurricane impacting the United States coastline in 2012. On June 6, Tropical Storm Risk released their second updated forecast for the season, predicting fourteen named storms, six hurricanes, and three major hurricanes. In addition, the agency called for an Accumulated Cyclone Energy index of 100. Near-average sea surface temperatures and slightly elevated trade winds for cited for lower activity compared to the 2010 and 2011 hurricane seasons. Tropical Storm Risk continued with their forecast of a near-average probability of a United States impact during the season using the 1950–2011 long-term normal, but a slightly below-average chance of a United States landfall by the recent 2002–2011 normal.
On August 9, 2012, the NOAA issued their mid-season outlook for the remainder of the 2012 season, upping their final numbers. The agency predicted between twelve and seventeen named storms, five to eight hurricanes, and two to three major hurricanes. Gerry Bell cited warmer-than-normal sea surface temperatures and the continuation of the high activity era across the Atlantic basin since 1995.
Seasonal summary
The Atlantic hurricane season officially began on June 1, 2012. It was an above average season in which 19 tropical cyclones formed. All nineteen depressions attained tropical storm status, and ten of these became hurricanes. However, only two hurricanes further intensified into major hurricanes. In fact, this was the first season since 2006 not to have a hurricane of at least Category 4 intensity. The season was above average most likely because of neutral conditions in the Pacific Ocean. Three hurricanes (Ernesto, Isaac, and Sandy) and three tropical storms (Beryl, Debby, and Helene) made landfall during the season and caused 304 deaths and around $ $72.3 billion in damages. Additionally, Hurricanes Leslie and Rafael also caused losses and fatalities, though neither struck land.
The last storm of the season, dissipated on October 29, over a month before the official end of the hurricane season on November 30.
Tropical cyclogenesis began in the month of May, with Tropical Storms Alberto and Beryl. This was the first occurrence of two pre-season tropical storms in the Atlantic since 1951. Additionally, Beryl is regarded as the strongest pre-season tropical cyclone landfall in the United States on record. In June, there were also two systems, Hurricane Chris and Tropical Storm Debby. However, no tropical cyclones developed in the month of July, the first phenomenon since 2009. Activity resumed on August 1, with the development of Hurricane Ernesto. With a total of eight tropical storms in August, this ties the record set in 2004.