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2006 Atlantic hurricane season
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The 2006 Atlantic hurricane season officially ran from June 1 to November 30, 2006. In contrast to the previous season, it was significantly less active. It is also the first since 2001 in which no hurricanes made landfall in the United States and the first since 1994 that no tropical cyclones formed during October.
Following the intense activity of 2005, forecasts predicted that the 2006 season would be only slightly less active.
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Encyclopedia
The 2006 Atlantic hurricane season officially ran from June 1 to November 30, 2006. In contrast to the previous season, it was significantly less active. It is also the first since 2001 in which no hurricanes made landfall in the United States and the first since 1994 that no tropical cyclones formed during October.
Following the intense activity of 2005, forecasts predicted that the 2006 season would be only slightly less active. But activity was slowed by a rapidly forming El Niño event in 2006, the presence of the Saharan Air Layer over the tropical Atlantic, and the steady presence of a robust secondary high pressure area to the Azores high centered around Bermuda. There were no tropical cyclones after October 2.
Tropical Storm Alberto was responsible for two indirect deaths when it made landfall in Florida. Hurricane Ernesto caused heavy rainfall in Haiti, and directly killed at least seven in Haiti and the United States. Four more hurricanes formed after Ernesto, including the strongest storms of the season, Hurricanes Helene and Gordon. In total, the season was responsible for 14 deaths and $500 million (2006 USD) in damage. The calendar year 2006 also saw Tropical Storm Zeta, which arose in December 2005 and persisted until early January, only the second such event on record. The storm can be considered a part of the 2005 and 2006 seasons, although it occurred outside the June 1–November 30 windows during which most Atlantic basin tropical cyclones form.
Seasonal forecasts
Forecasts of hurricane activity are issued before each hurricane season by noted hurricane experts Philip J. Klotzbach, Dr. William M. Gray, and their associates at Colorado State University; and separately by NOAA forecasters.
Klotzbach's team (formerly led by Gray) has defined the average number of storms per season (1950–2000) as 9.6 tropical storms, 5.9 hurricanes, and 2.3 major hurricanes (storms exceeding Category 3 strength in the Saffir-Simpson Hurricane Scale). A normal season, as defined by NOAA, has 6–14 named storms, with 4–8 of those reaching hurricane strength, and 1–3 major hurricanes.
Predictions of tropical activity in the 2006 season | Source | Date | Named
storms | Hurricanes | Major
hurricanes | | CSU | Average (1950–2000) | 9.6 | 5.9 | 2.3 | | NOAA | Average | 6–14 | 4–8 | 1–3 | | Record high activity from 1950–2006 | 28 | 15 | 8 | | Record low activity from 1950–2006 | 4 | 2 | 0 | | CSU | 5 December 2005 | 17 | 9 | 5 | | CSU | 4 April 2006 | 17 | 9 | 5 | | NOAA | 22 May 2006 | 13–16 | 8–10 | 4–6 | | CSU | 31 May 2006 | 17 | 9 | 5 | | CSU | 3 August 2006 | 15 | 7 | 3 | | NOAA | 8 August 2006 | 12–15 | 7–9 | 3–4 | | CSU | 1 September 2006 | 13 | 5 | 2 | | CSU | 3 October 2006 | 11 | 6 | 2 | | Actual activity | 10 | 5 | 2 |
Pre-season forecasts
On December 5, 2005, Klotzbach's team issued its initial extended-range forecast for the 2006 season, predicting an above average of 17 named storms, nine of them hurricanes, and five classified as Category 3 intensity or higher.
As in the 2005 season, the team predicted it was highly probable that at least one major hurricane would directly impact the United States. The forecast suggested an 81% probability that at least one major hurricane would strike the U.S. mainland, a 64% chance of at least one major hurricane striking the East Coast of the United States (including the Florida peninsula), and a 47% chance of at least one major hurricane striking the Gulf Coast of the United States from the Florida Panhandle westward. The team also predicted that the potential for major hurricane activity in the Caribbean was above average. A few months later, on April 4, 2006, CSU issued another forecast confirming its December predictions.
On May 22, 2006, NOAA released its pre-season forecast for the 2006 season. The prediction was for 13–16 named storms, 8–10 of those becoming hurricanes, and 4–6 becoming major hurricanes.
On May 31, 2006, Klotzbach's team released its final pre-season forecast for 2006, confirming its earlier prediction.
Midseason outlooks
On August 3, 2006, Klotzbach's team lowered its season estimate to 15 named storms, with 7 becoming hurricanes and 3 becoming major hurricanes, noting that conditions had become less favorable for storms than they had been earlier in the year. The sea-level pressure and trade wind strength in the tropical Atlantic were reported to be above normal, while sea surface temperature anomalies were on a decreasing trend.
On August 8, 2006, NOAA revised its season estimate to 12–15 named storms, with 7–9 becoming hurricanes and 3–4 becoming major hurricanes. The reduction was attributed to less favorable environmental conditions, a decrease in La Niña conditions, and the lack of a "very persistent upper-level ridge pattern over the eastern U.S. and western Atlantic."
On September 1, Klotzbach's team also revised its season estimate, to 13 named storms, 5 hurricanes and 2 major hurricanes, citing a larger volume of the Saharan Air Layer and an El Niño trend in the Pacific. The team again reduced the number of tropical storms expected for the season a month later, on October 3, with an updated forecast of 11 named storms, 6
hurricanes and 2 major hurricanes, citing the ongoing El Niño.
Storms
Tropical Storm Zeta (2005)
Tropical Storm Zeta formed on December 30, 2005, and lasted until January 6, 2006. Although the majority of its existence was spent in 2006, it is officially a storm of the 2005 Atlantic hurricane season, because it formed in 2005. Zeta joined Hurricane Alice as only the second Atlantic tropical cyclone in recorded history to span two calendar years.
June and July
The official start of the Atlantic hurricane season is June 1, which is just before Tropical Storm Alberto developed on June 10 in the northwestern Caribbean. It tracked northeastward through the Gulf of Mexico, reaching an intensity of 70 mph (110 km/h) on June 13 before making landfall near Adams Beach, Florida, on June 14. Losing its tropical characteristics, Alberto moved northward and produced heavy rainfall in South Carolina and North Carolina. The remnants tracked off the East Coast and transitioned into a powerful extratropical storm which affected Nova Scotia with high winds, heavy rain, and rough surf, leaving four fisherman missing offshore. Alberto caused record rainfall in North Carolina, peaking at 8 inches (200 mm).
In Florida, two people died, and damage estimated at $250,000 (2006 USD) was caused.
On July 17, a cold front moved off the Northeast United States coast and stalled; the tail end of the front spawned a low pressure system which tracked to the northeast along the front. Convection increased for a short time, before reaching colder waters and dissipating. Although the system was not believed to be tropical during its existence, post-season analysis revealed that it had attained tropical characteristics for 30 hours, and so it was designated an unnamed tropical storm.
A frontal system moved off the North Carolina coast and spawned a low pressure system east of North Carolina on July 18. Associated with deep convection, the storm organized sufficiently to be upgraded to Tropical Storm Beryl on July 19. It tracked northeast and passed over Nantucket before dissipating on July 21, having had no major effects on land.
August
By late July, a tropical wave moved off the coast of Africa and traversed the Atlantic Ocean. The associated convection organized, and became a tropical depression on July 31. The depression tracked westward and soon intensified into Tropical Storm Chris before reaching peak winds of 65 mph (100 km/h), just before weakening and passing over Cuba as a tropical depression. The storm's effects were limited to moderate rainfall in Hispaniola and Cuba.
On August 20, a tropical wave moved off the coast of Africa associated with deep convection. The next day, it spanwed a system which was classified as a tropical depression while situated south of the Cape Verde Islands. On August 22, the depression was upgraded to Tropical Storm Debby. Debby passed south of the Cape Verde Islands and reached peak intensity of 50 mph (85 km/h) before turning north and dissipating without affecting any land masses.
Hurricane Ernesto originated from a tropical wave which moved off the coast of Africa on August 18. The wave progressed westward and reached the Western Atlantic, spawning a tropical depression on August 24. On August 25 the depression was upgraded to Tropical Storm Ernesto, and the storm was briefly upgraded to a hurricane before striking Florida as a weak tropical storm. Ernesto moved off the U.S. East Coast and made a second landfall on North Carolina before moving inland and dissipating over Canada. Overall, the storm caused $500 million (2006 USD) in the United States and killed at least eleven people, five of them in the United States, and five in Haiti.
September and October
Hurricane Florence originated on September 3 from the complex merging of two tropical waves, creating one large low pressure area. The disturbance moved westward and became a tropical depression in the open waters of the Atlantic. On September 5, it organized further and was upgraded into Tropical Storm Florence. Florence tracked west-northwest and intensified into a hurricane on September 10 while south of Bermuda. The storm passed just to the east of Bermuda as a Category 1 hurricane on the Saffir-Simpson hurricane scale as it reached its peak intensity of 90 mph (145 km/h). It moved north before losing its tropical characteristics and passing over the Canadian Maritimes as a strong extratropical storm. Florence affected Bermuda with wind gusts up to 115 mph (185 km/h) and heavy rain which left 23,000 houses without electricity. In all, the storm caused $200,000 (2006 USD) in damage.
A tropical wave moved off the coast of Africa on September 1. The wave tracked westward across the Atlantic for several days until it reached an area of relaxed wind shear and its associated low pressure area organized into a tropical depression. It moved east-northeast and was upgraded to Tropical Storm Gordon on September 11, while located over the open waters of the Atlantic. Gordon turned north, and became a hurricane on September 13. It intensified to Category 3 status on the Saffir-Simpson hurricane scale and reached its peak intensity of 120 mph (195 km/h) on September 14. Tracking northward, it began to lose tropical characteristics. On September 20, the system affected Britain with high winds and heavy rain as an extratropical cyclone. During Gordon's passage through Britain, 120,000 homes were left without power after winds of 80 mph (130 km/h) affected the country.
On September 11, a vigorous tropical wave moved off the west coast of Africa. The wave organized rapidly and spawned a tropical depression to the south-southeast of the Cape Verde Islands. On September 14, the depression intensified into Tropical Storm Helene while tracking west-northwest. Helene continued to intensify and was upgraded to a hurricane on September 16. The storm began to execute a northward track, and reached Category 3 hurricane status on the Saffir-Simpson hurricane scale on September 18, before reaching its peak intensity of 120 mph (195 km/h). It started to weaken when it reached the cold waters of the North Atlantic, and Helene dissipated on September 20, without having had major effects on land other than moderate wind gusts in the British Isles.
Hurricane Isaac originated in a tropical wave that moved off the coast of Africa on September 18. The wave tracked west, produced a tropical depression, and became a tropical storm on September 28. Isaac moved north-northwest and was upgraded to a hurricane on September 30. It turned north and reached its peak intensity of 85 mph (135 km/h) before weakening and brushing Nova Scotia. Isaac did not affect any land or shipping lanes.
Impact
Compared to the previous 2005 Atlantic hurricane season, 2006 was not severe in terms of deaths and damage. The season was unusual in that no hurricanes made landfall in the United States, the first such occurrence since 2001. However, three tropical storms made landfall in the United States; the first of them, Tropical Storm Alberto, made landfall in Florida with winds of 50 mph (80 km/h). The storm moved inland, and produced 6–7 inches (150–175 mm) of rain in the area of landfall, and in North Carolina. A total of three indirect deaths resulted from the storm. Tropical Storm Beryl made landfall on Nantucket, causing little or no damage. It generated high waves along the East Coast of the United States, with 19-foot (6 m) seas in the open ocean. The third and more significant storm was Hurricane Ernesto, which killed two people in Virginia. Ernesto made landfall in the Florida Keys, and later made landfall in Miami-Dade county. It moved north and dissipated over Virginia while causing severe flooding. In addition to the two fatalities, the floods left $500 million (2006 USD) in damages.
During the season, only one tropical cyclone in the Atlantic basin affected Mexico. Tropical Storm Alberto dropped light amounts of rainfall across the country, with a 24–hour total peaking at 4 inches (100 mm) in Peto, Yucatán. Light rain was also reported throughout Quintana Roo and in eastern Campeche.
Canada was affected by several tropical cyclones during 2006; as Tropical Storm Alberto was becoming extratropical, its remnants spawned strong winds across the Canadian Maritimes, including gusts of 74 mph (119 km/h) in the Barrington district of Nova Scotia. It is reported that the passage of the storm left four sailors missing about 230 miles (370 km) south of Nova Scotia. As an unnamed tropical storm entered the area of responsibility of the Canadian Hurricane Centre, a buoy recorded sustained winds of 36 mph (56 km/h) with gusts up to 44 mph (70 km/h). The remnants of Tropical Storm Beryl dropped moderate precipitation in Atlantic Canada, officially peaking at 2.8 inches (71 mm) in Scotts Bay, Nova Scotia with an unofficially higher total of 3.5 inches (88 mm); in some locations 1 inch (25 mm) of rain fell in an hour. Moderate winds were reported along its path, which peaked at 60 mph (96 km/h) in southern Nova Scotia. As an extratropical storm over Newfoundland, Hurricane Florence produced powerful winds peaking at 101 mph (163 km/h) and moderate amounts of rainfall of up to 2.6 inches (67 mm). Additionally, Hurricane Isaac produced moderate winds on land in Newfoundland, peaking at 60 mph (96 km/h) with a sustained wind of 46 mph (74 km/h) was recorded.
Hurricane Florence passed to the east of Bermuda as a Category 1 hurricane, producing wind gusts of up to 115 mph (185 km/h), which caused several power outages and minor damage. Florence then brought heavy rains across Newfoundland as an extratropical storm, destroying one house and causing minor damage to several others. There were no fatalities as a result of the hurricane.
Parts of the United Kingdom were affected by Hurricane Gordon, which moved through the Atlantic reaching Category 3 intensity on the Saffir-Simpson hurricane scale, before turning towards the North Atlantic. Winds of 80 mph (130 km/h) were reported in Britain, and after Gordon's passage 120,000 homes were left without power.
Lack of activity
The National Hurricane Center's pre-season activity outlook predicted 13–16 named storms, 8–10 hurricanes and 4–6 major hurricanes.
They also predicted a high risk of at least one major hurricane strike to the Southeast United States. In the event, only ten storms formed during the season, the lowest number since the 1997 season, when there were seven. Five of the ten storms developed into hurricanes—also the lowest number since 1997—and only two attained major hurricane status, tying with 2002 for the fewest since 1997. Only two named storms were observed during October, the lowest number since 1994, when none were seen during that month. Additionally, only three named storms made landfall in the United States, the fewest since 2001. Because of several factors, including a rapidly forming El Niño event, Saharan Air Layer over the tropical Atlantic and the presence of high pressure area to the Azores high situated near Bermuda contributed to a below average season.
Also, sea surface temperatures in the western Atlantic were just at or slightly below average. In contrast, sea surface temperatures during the 2005 season were well above average.
Accumulated Cyclone Energy (ACE) rating
The table on the right shows the ACE for each storm in the season. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. ACE is only calculated for full advisories on tropical systems at or exceeding 35 knots (39 mph/63 km/h), or tropical storm strength. The highest ever ACE estimated for a single storm in the Atlantic is 73.6, for Hurricane San Ciriaco in 1899. This single storm had an ACE higher than many whole Atlantic storm seasons. Other Atlantic storms with high ACEs include Hurricane Ivan in 2004, with an ACE of 70.4, and Hurricane Donna in 1960, with an ACE of 64.6.
The cumulative ACE for the 2006 season was toward the lower end of the official "Near Normal" grading. The number of tropical storms and hurricanes was near the long-term average. Hurricane Helene had the highest rating of the season with a total ACE of 24.3, and Hurricane Gordon came in second highest, having a total ACE of 22.2. The unnamed tropical storm had the lowest, totaling to 0.654. The season total ACE was 78.535.
Storm names
The names listed were used for named storms formed in the North Atlantic during 2006. No names were retired, and so this list will be reused in its entirety for the 2012 season. The list is the same as that used in the 2000 season except for Kirk, which replaced Keith. No storm was given a previously unused name, for the first time since the 1993 season. It was the first hurricane season since the 1997 season that no Atlantic names were retired. It was also the first (and so far, only) hurricane season of the 21st century that no names have been retired.
The World Meteorological Organization determined at its annual meeting in the spring of 2006 to again use names from the Greek alphabet, starting with Alpha, if the main list should become exhausted.
Season impact
See also
External links
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- – updated four times daily
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- for tropical cyclones which affected the United States in 2006
- – includes map of paths of all storms
- – track active and archived hurricanes.
- – Naval Research Laboratory page with extensive archives on individual storms
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