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Superstorm Sandy was the headline event of the 2012 tropical cyclone season, but it was northwest Pacific typhoon Bopha which was the most devastating storm of 2012, leading to over 1000 deaths across the Philippines. Sandy battered the Caribbean islands before heading up the US east coast towards New York City just a year after hurricane Irene struck the same part of the US coast. Sandy was a very different type of storm from Irene: a hybrid of tropical and extra-tropical systems leading to a ‘superstorm’ with a wind-field that, by the time Sandy made landfall on the US east coast, extended over 1800km in diameter.

This article will take a look at the overall activity within each tropical cyclone basin, along with what was expected for 2012, with a review of how the seasonal forecasts measured up to actual tropical cyclone activity, before summarizing the main events in each tropical cyclone basin. Finally, we include a brief overview of extended range forecasts for the coming year.

North Atlantic Basin 2012 season summary

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

The recent trend of above-average tropical storm activity in the North Atlantic Basin continued in 2012, with the season marking the third in a row with 19 named storms. This places the 2012 north Atlantic hurricane season joint second highest for named storms, based on historical records since 1944, beaten only by 2005, which had 28 named storms. Ten of these tropical storms developed into hurricanes (with winds over 118kmh−1 (73mph)), but only one became a major hurricane (with winds over 177kmh−1 (110mph)). Anomalous sinking motion at mid-levels in the atmosphere was thought to be the primary reason that 2012 did not see a greater number of major hurricanes (Klotzbach and Gray, 2012). The accumulated cyclone energy (ACE) index, which provides an evaluation of seasonal activity using a combined measure of a basin's cyclone intensities and durations, was 129 for the North Atlantic Basin in 2012, an above average measure that reflected an unusual season with a high number of weaker storms but little major hurricane activity.

The 2012 season also followed another trend seen in the two previous seasons: high overall activity but few storms making landfall in the US. Throughout the season, the majority of storms were steered away from the US by a mid-level trough and strong southwesterly flow over the western north Atlantic. Additionally, a weak Atlantic subtropical high meant that storms developing in the far eastern Atlantic tended to re-curve and intensify into hurricanes north of the area across the tropical Atlantic and Caribbean Sea that is named the Main Development Region (MDR) where the majority of hurricanes in an active season form (Goldenberg et al., 2001). These conditions concentrated activity on the northeast subtropical Atlantic and led to only two hurricanes making landfall in the US (Isaac and Sandy). Furthermore, the pressure pattern in the subtropical north Atlantic led to tropical storms forming in the western MDR moving westwards and entering the Caribbean Sea and the Gulf of Mexico. Two of these tropical storms (Ernesto and Isaac) later strengthened into hurricanes before making landfall along the Yucatan Peninsula and the US coast of Louisiana, respectively. Four storms entered or formed in the Caribbean Sea; only two storms, Isaac and Debby, entered or formed in the northern Gulf of Mexico.

North Atlantic Basin 2012 seasonal forecasts

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

Colorado State University (CSU) issued a forecast prior to the onset of the season (in early April) that predicted a below-average season with 10 named storms, 4 of these developing into hurricanes, and an overall ACE measure of 70. Through the season this forecast was adjusted upwards, but still under-predicted the actual basin activity (Klotzbach and Gray, 2012). The CSU seasonal forecast is based on an evolving combination of empirically-determined hurricane precursor signals, including the El Niño–Southern Oscillation (ENSO), Atlantic sea surface temperatures (SSTs) and sea-level pressures, West African rainfall, the Quasi-Biennial Oscillation (QBO) and a number of other global parameters.

The National Oceanic and Atmospheric Administration's seasonal forecast (NOAA Climate Prediction Center, 2012), issued in late May, also under-predicted activity, with a forecast of between 9 and 15 named storms; they commented that uncertainty in the outlook depended on whether or not El Niño conditions would develop. University College London's Tropical Storm Risk (TSR) consortium issued a pre-season forecast in December 2011, correctly predicting an above-average hurricane season based on two key predictors of trade wind speed over the Caribbean Sea and the tropical north Atlantic and SSTs across the Atlantic MDR (Saunders and Lea, 2011). However, the forecast was updated prior to and during the season to near-normal activity.

The UK Met Office produced dynamical forecasts of tropical cyclone activity for the North Atlantic Basin every month from March to August, using combined output from the Met Office and European Centre for Medium Range Weather Forecasts (ECMWF) seasonal forecasting systems. These forecasts provided good guidance on the basin's activity, with the observed ACE index being within the predicted range for all but July's monthly updates. However, although the forecasts of named-storm numbers agreed well with observed activity for forecasts issued in March, May and August, the number of storms forecast in the April, June and July updates was under-predicted (Met Office, 2012).

The underestimation of 2012 tropical cyclone activity was probably due to an expectation of positive ENSO conditions. Forecasts predicted a warming of SSTs in the tropical Pacific Niño 3.4 region (120°W–170°W, 5°N–5°S: an area monitored to determine the phase of the ENSO). Positive ENSO conditions, through an atmospheric teleconnection response, led to high vertical wind shear (the difference in horizontal wind between the upper and lower atmosphere) over the tropical Atlantic MDR, disrupting the vertical organization of developing storms, therefore preventing storm development and intensification. However, the observed El Niño conditions were only weakly positive and the typical atmospheric response to El Niño did not develop. Therefore the suppression of tropical storm activity that would typically occur in the Atlantic during an El Niño event did not happen.

It has been suggested that since 2000, due to improved observational capabilities, there has been an increase in the number of weaker and shorter-lived storms detected (Landsea et al., 2010), which could skew recent seasonal summaries when they are compared to climatology.

North Atlantic Basin 2012 key storms

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

Storm activity in the North Atlantic Basin in 2012 started early, with Alberto forming off the coast of South Carolina on 19 May, nearly two weeks before the official start of the season. Alberto was a compact storm with a tight centre of circulation, which rapidly intensified to maximum winds of nearly 80kmh−1 (50mph). The storm remained offshore, moving to the northeast, but led to dangerous surf conditions and rip currents along the Georgia, South Carolina and northeast Florida coastlines. Tropical storm Beryl followed, also forming prior to the official season start, making landfall in Florida on 28 May. Tropical storm Debby, forming in the Gulf of Mexico, then made landfall in Florida on 26 June, leading to river flooding across the state. After this active start to the season, no storms formed during July. However, activity picked up again in August, during which eight tropical storms formed, tying the record for the most named storms in a single month set in 2004.

Hurricane Isaac struck New Orleans on 29 August on the seventh anniversary of Katrina's devastating landfall: Isaac was a much less damaging storm, but its wind and storm-surge impacts along the Gulf Coast were still responsible for over 40 deaths and insured losses of approximately $2 billion.

Hurricane Michael was the only tropical cyclone to develop to major hurricane strength (winds greater than 177kmh–1). It should be noted that Michael formed outside the tropics, and in fact only two of the ten hurricanes of 2012 attained hurricane strength within the MDR. It is possible that although the weak El Niño conditions were insufficient to weaken tropical cyclone formation, the atmospheric El Niño teleconnection response did suppress intensification of storms. This would have limited storm contribution to the overall ACE index for the season, which was relatively low given the high number of tropical storms that occurred.

Hurricane Nadine followed a looping path in the Atlantic, and was reported by NASA to have lasted 23 days (10 September to 3 October), the second longest duration for an Atlantic tropical storm since 1851, beaten only by Ginger in 1971.

Superstorm Sandy

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

Tropical Storm Sandy developed on 22 October from an area of low pressure in the Caribbean Sea to the south of Jamaica. Warm water provided a source of energy allowing it to intensity rapidly to a category 1 hurricane on the Saffir-Simpson scale by 24 October. It first made landfall on Jamaica on the 24th, with winds of nearly 130kmh−1 (80mph), then strengthened further into a category 2 hurricane before making a second landfall in eastern Cuba. Sandy caused widespread devastation across the Caribbean islands of Haiti, Jamaica, Cuba and the Dominican Republic, where thousands of farms were damaged, destroying large areas of staple crops.

As Sandy travelled northwards, it passed through the Bahamas, briefly weakening to a tropical storm, before re-intensifying to hurricane status. By now, its wind-field had begun to expand and tropical storm-force winds were being recorded up to 725km from its centre (NHC, 2012). By 27 October, it was being steered to the northeast by an upper-level low over the eastern US. An anomalously strong high-pressure area over Atlantic Canada and Greenland and a stationary cold front over the Appalachians then blocked its northeastward movement (Figure 1); instead, it was steered to the northwest, towards the northeast US coast. Warm moist air circulating within Sandy then met cold air spreading south into the northeastern US from Canada. Strong baroclinic interaction, due to the temperature contrasts between the two masses of air, gave the storm additional energy, allowing it to maintain its hurricane-strength winds and expand even further (Figure 2). As Sandy metamorphosed from a warm core (tropical) storm to a cold core (post-tropical) storm, it became more like a Nor'easter, a familiar type of storm along the eastern coast of the US.

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Figure 1. NOAA’s GOES-13 satellite visible image for 28 October 2012, capturing the huge size of hurricane Sandy. The line of clouds is associated with the cold front that Sandy is merging with. (Courtesy of NASA/NOAA GOES Project.)

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Figure 2. Indian Space Research Organisation's (ISRO) OceanSat-2 satellite, OSCAT radar scatterometer image for 28 October 2012, capturing ocean surface winds for Hurricane Sandy. Colours indicate wind speed and arrows indicate direction. The image shows the large extent of high winds associated with the system. (Courtesy of ISRO/NASA/JPL-Caltech.)

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On 29 October Sandy finally made landfall on the US east coast to the south of New York. Although wind speeds had slowed to around 150kmh−1 (90mph) by this stage (category 1 hurricane strength), the storm was now over 1800km in diameter, leading to impacts over a huge area. Landfall coincided with a full-moon spring tide, magnifying the effects of the storm surge along several hundred kilometres of coast, from New Jersey to Massachusetts. The storm surge mainly occurred along the north side of the storm; at Bergen Point, New Jersey, it reached a height of 4.3m. A storm surge also led to the flooding of a number of New York's subway tunnels for the first time in 100 years. Indeed, most of the damaging impact of Sandy was related to the storm surge rather than wind damage.

A state of emergency was declared in nine US states, and disruption along the east coast included the cancellation of over 15 000 flights, loss of power to an estimated 8.5 million people, including across New York City, and closure of the New York Stock Exchange due to ‘adverse weather’ for the first time in 27 years.

River flooding also occurred as a consequence of long periods of heavy rainfall. Rainfall totals of over 180mm were recorded in many areas near the Atlantic coast from New Jersey to South Carolina (NASA, 2012). As Sandy moved inland it then brought blizzards to the mountains of southwest Pennsylvania, western Maryland, West Virginia, eastern Tennessee, eastern Kentucky and extreme western North Carolina. The extensive remnant cloud field of Sandy lingered over a large area of the northeastern US and Canada into early November.

Munich Re estimated overall losses from Sandy to be around US$50 billion, with insured losses of around US$25 billion, the largest natural catastrophe loss event of 2012. 210 deaths were attributed to the storm, with 80 of those in the Caribbean islands alone (Munich Re, 2013).

Northwest Pacific Basin

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

The Northwest Pacific Basin also experienced above-average tropical cyclone activity during the 2012 season, with 25 tropical storms, 16 of which developed into typhoons (as observed by the Joint Typhoon Warning Center, JTWC) and 5 of those into intense typhoons. Although the official start of the season is 1 January, the majority of the tropical storms in this basin occur between May and November.

Seasonal forecasts of storm activity in the Northwest Pacific Basin are issued by agencies including University College London's Tropical Storm Risk (TSR), the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) and the Taiwan Central Weather Bureau (CWB). TSR issue forecasts each month from April to August of the expected overall number of tropical storms, typhoons and intense typhoons, and the ACE index for the season expressed as deterministic and probabilistic projections. During 2012, TSR made accurate predictions of both the overall number of storms and the number of typhoons, but over-predicted the number of intense typhoons. The main predictor used within these forecasts is that of SSTs in the Niño 3.75 region (180°–140°W, 5°S–5°N) ): for August to September the Niño 3.75 SSTs were predicted to be above normal.

Pakhar was the first typhoon to develop in the Northwest Pacific basin, first appearing as a tropical disturbance in the South China Sea on 17 March, with little movement for some time allowing it to build strength from the warm surface waters. On 29 March, it rapidly intensified, with wind speeds (1–minute maximum sustained) increasing from 65kmh−1 (40 mph) to 111kmh−1 (69mph) in just 12 hours in response to an environment of low wind shear and high SSTs. On 1 April, Pakhar made landfall on southeastern Vietnam, damaging thousands of homes, causing flooding and leading to two deaths. But even before it had become a tropical cyclone, heavy rain associated with the depression brought flash flooding and landslides to the Philippines.

Intense typhoon Guchol affected Japan during June, leading to the evacuation of over 1500 residents to the southwest of Tokyo and the cancellation of hundreds of domestic and international flights due to strong winds associated with the storm. Guchol achieved maximum sustained winds of nearly 200kmh−1 (125mph).

Tropical cyclones developing in the northwest Pacific threaten many countries in eastern Asia. During July Khanun made landfall on western South Korea, affecting both South and North Korea, and intense typhoon Vicente made landfall in the Guangdong province of China. During August, China was affected by typhoons Saola, Damrey, Haikui and Kai-tak, Taiwan by typhoon Saola and intense typhoon Tembin, Vietnam by typhoon Kai-tak, and Japan and North Korea by intense typhoon Bolaven.

Intense typhoon Sanba was the strongest typhoon to occur in the basin with a central pressure of 900mbar and 1-minute maximum sustained winds of 280kmh−1. Sanba formed from an area of low pressure on 9 September, and made landfall in South Korea on 17 September with heavy rain, falling at a rate of over 90mmh−1, leading to landslides, flooding, and at least one death. Rainbands associated with the storm were still producing rain as far away as Japan.

Whilst Atlantic hurricane Sandy led to the largest economic loss, typhoon Bopha led to the largest human loss with over 1000 fatalities in early December in the Philippines. Bopha gathered strength from warm Pacific water during late November, and by the time it made landfall in the Philippines it had reached intense typhoon status, with 1-minute maximum sustained winds of 260kmh−1 (160mph) and a well-defined eye. On 3 December, just prior to it making landfall, the NASA Tropical Rainfall Measuring Mission (TRMM) satellite captured concentric rings of storm cells, revealing a double eye-wall, which is evidence of eye-wall replacement and an indicator of rapid intensification (Figure 3). The typhoon brought high winds and heavy rains to the Philippines, causing devastating flooding and landslides. The heaviest rain, estimated at over 240mm, fell near the coast of eastern Mindanao, and totals of over 100mm were reported over a large area of the southern Philippines. Bopha finally dissipated in the South China Sea on 9 December. Bopha was a rare storm, in that it intensified to category 5 super typhoon and made landfall at only 6°, unusually near the equator. The Philippines were hit again in late December by tropical storm Wukong.

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Figure 3. NASA Tropical Rainfall Measuring Mission (TRMM) satellite visualization, capturing typhoon Bopha in 3D as it moved through the western North Pacific Ocean. The radar reveals a double eyewall, with two concentric rings of intense storm cells. Yellows and greens indicate locations inside the typhoon's clouds where updraughts were lifting precipitation-size ice between 9 and 12km above the ocean (Courtesy of NASA/Owen Kelley.)

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East Pacific Basin

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

NOAA's Climate Prediction Center's pre-season outlook for the East Pacific Basin gave a 50% chance of a near-normal season with an estimate of 12–18 named storms, 5–9 of those becoming hurricanes and 2–5 becoming major hurricanes. This forecast was based on predicted increased wind shear and the possible development of El Niño later in the season, after La Niña conditions at the beginning of the season. In the event, neutral ENSO conditions prevailed across the season, and 2012 turned out to be moderately active in the east Pacific, at the upper bounds of the CPC pre-season forecast, with 17 named storms, 10 of which intensified into hurricanes and 5 into major hurricanes.

The season started with tropical storm Aletta, which formed a day before the start of the official season on 14 May, but unfavourable tropical atmospheric conditions, including wind shear and a low-pressure trough, soon led to its dissipation. However, as Aletta was weakening, Bud was forming; this reached category 3 strength on 24 May with sustained winds of 185kmh−1 (115mph) and a minimum central pressure of 961mbar. This was the earliest date for a storm of this strength on record for the East Pacific Basin (NOAA Climate Prediction Center, 2012). Bud made landfall as a tropical depression on the western coast of Mexico on 26 May. Hurricane Carlotta made landfall on the south-western coast of Mexico on 16 June, causing seven deaths and damage estimated at costing over US$100 million. Heavy rains, falling at 50mmh−1, caused flooding and landslides as it moved inland.

July was an active month in this basin, with three storms reaching hurricane strength, and two of those attaining major hurricane strength, but with no landfall.

Hurricane Paul was the only other storm to cause any significant damage when it brushed past the Baja California Peninsula in October. Paul rapidly intensified to a category 3 hurricane in response to favourable environmental conditions of warm water, low wind shear and high relative humidity, but it weakened to a tropical depression prior to making landfall.

North Indian Ocean Basin

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

Five depressions formed during the 2012 north Indian Ocean cyclone season, three in the Bay of Bengal and two in the Arabian Sea. Only two of the depressions developed into cyclonic storms, both of which made landfall. The 2012 cyclone season began very late in this basin, on 10 October when a depression formed from remnants of northwest Pacific severe tropical storm Gaemi (discussed above). The depression brought heavy rain and high winds to much of Bangladesh, leading to over 40 deaths, many of them fishermen, and extensive damage to thousands of dwellings. Cyclonic storm Murjan formed in the Arabian Sea, making landfall over Somalia on 25 October. While Murjan caused flooding in the city of Bosaso, it also brought beneficial rains to the Bari region. Cyclonic storm Nilam made landfall, with peak wind speeds of 102kmh−1, over southern India on 31 October, bringing torrential rains to northern Sri Lanka and south India, leading to 75 deaths.

Southern Hemisphere Tropical Cyclone Basins

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

The 2012/2013 tropical cyclone seasons in the Southern Hemisphere were ongoing at the time of writing. The southwest Indian Ocean experienced five tropical storms up to early January 2013, three of which intensified into cyclones, and two of those to intense tropical cyclones, including Anais in mid-October, which was the earliest known intense tropical cyclone to develop in this region. Anais made landfall on Madagascar as a tropical depression. No other storm in this basin had made landfall into early 2013.

In the South Pacific Basin, seasonal forecasts made by the Island Climate Update (ICU) forum (which includes the New Zealand National Institute of Water and Atmospheric Research (NIWA), the Australian Bureau of Meteorology (BoM) and Pacific Island Meteorological Services) were based on assessments of ENSO conditions. If an El Niño developed this could increase both the number and intensity of storms; however, expected neutral ENSO conditions led to a forecast of near-normal activity. Both the two tropical cyclones to develop by early 2013 reached severe tropical cyclone strength: Evan hit the Pacific islands of Samoa and Fiji in mid-December with wind gusts up to 230kmh−1 (143mph). 14 people were killed on Samoa and there was widespread flooding and wind damage. Severe tropical cyclone Freda developed during late December and early January, hitting the Solomon Islands and New Caledonia with strong winds and heavy rain, leaving thousands without power.

Summaries are also made for tropical storms affecting the Australian region spanning a region between 90°E and 160°E. Seasonal forecasts are issued by NIWA, BoM, the National Climate Centre and the Guy Carpenter Asia-Pacific Climate Impact Centre. BoM's forecasts took into account current neutral ENSO conditions and forecast below-average tropical cyclone activity for the whole region. By mid January, three tropical cyclones had developed, with one, Narelle, reaching severe tropical cyclone intensity with peak winds of 205kmh−1 (127mph) on 12 January 2013.

Extended range forecasts issued for 2013

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References

Extended range forecasts already issued for the 2013 tropical cyclone seasons focus on the North Atlantic Basin, where above-average (compared with the 1950–2012 mean) activity is anticipated (Saunders and Lea, 2012), based on current and projected climate signals. However, these extended forecasts stress the large uncertainties this far ahead, with CSU stating that the one of the big uncertainties for the 2013 Atlantic hurricane season is whether or not El Niño will develop.

References

  1. Top of page
  2. North Atlantic Basin 2012 season summary
  3. North Atlantic Basin 2012 seasonal forecasts
  4. North Atlantic Basin 2012 key storms
  5. Superstorm Sandy
  6. Northwest Pacific Basin
  7. East Pacific Basin
  8. North Indian Ocean Basin
  9. Southern Hemisphere Tropical Cyclone Basins
  10. Extended range forecasts issued for 2013
  11. References
  • Goldenberg SB, Lansea CW, Mestas-Nuñez AM, Gray WM. 2001. The recent increase in Atlantic hurricane activity: causes and implications. Science 293: 474479.
  • Klotzbach PJ, Gray WM. 2012. Summary of 2012 Atlantic tropical cyclone activity and verification of author's seasonal and two-week forecasts. http://hurricane.atmos.colostate.edu/forecasts/2012/dec2012/dec2012.pdf [accessed 7 January 2013].
  • Landsea CW, Vecchi GA, Bengtsson L, Knutson TR. 2010. Impact of duration threshold on Atlantic tropical cyclone counts. Journal of Climate 23: 25082519.
  • Met Office. 2012. North Atlantic tropical cyclone seasonal forecast. http://www.metoffice.gov.uk/weather/tropicalcyclone/seasonal/northatlantic2012 [accessed 7 January 2013].
  • Munich Re. 2013. Press Release “Natural catastrophe statistics for 2012 dominated by weather extremes in the USA”. http://www.munichre.com/en/media_relations/press_releases/2013/2013_01_03_press_release.aspx [accessed 7 January 2013].
  • NASA. 2012. Hurricane Sandy (Atlantic Ocean) http://www.nasa.gov/mission_pages/hurricanes/archives/2012/h2012_Sandy.html [accessed 7 January 2013].
  • NOAA Climate Prediction Centre. 2012. NOAA 2012 Atlantic Hurricane Season Outlook Update. http://www.cpc.ncep.noaa.gov/products/outlooks/hurricane.shtml [accessed 7 January 2013].
  • Saunders and Lea. 2011. Extended range forecast for Atlantic Hurricane Activity in 2012. http://www.tropicalstormrisk.com [accessed 7 January 2013].
  • Saunders and Lea. 2012. Extended range forecast for Atlantic Hurricane Activity in 2013. http://www.tropicalstormrisk.com [accessed 7 January 2013].