Active 2006 Atlantic Hurricane Season to Be Less Busy than in 2005
While the 2006 Atlantic hurricane season is still expected to be "very active," the good news is it is not expected to rival the ferocity of last year's record-setting season, according to Colorado State University's Tropical Meteorology Project (TMP), headed up by respected researchers Philip J. Klotzbach and William M. Gray.
"We continue to foresee another very active Atlantic Basin tropical cyclone season in 2006," the researchers said. "Landfall probabilities for the 2006 hurricane season are well above their long-period averages."
While still a couple months away, the hurricane season is already the number one concern for the shaken energy industry, which saw hurricanes Katrina and Rita shut in more than 692 Bcf (and counting) of natural gas in the Gulf of Mexico, which represents 18.967% of the Gulf's yearly production. Despite near-record amounts of gas in storage, a major disruption to Gulf supplies could put gas markets in a pinch rather quickly.
In its 22nd year of forecasting, the TMP forecast for 2006 shows above normal hurricane activity for the Atlantic Basin but below that observed in the disastrous 2005 season. The April update showed no change from the group's December 2005 forecast (see Daily GPI, Dec. 7, 2005).
For 2006, the group forecasts 17 named storms, nine hurricanes, and five intense hurricanes. In 2005 there were 27 named storms, 15 hurricanes and seven intense hurricanes. Compared to the benchmark 1950 to 2000 period, the 2006 forecast is higher. For 1950 to 2000 there would typically be 9.6 named storms, 5.9 hurricanes and 2.3 intense hurricanes, the report showed.
"We have maintained our forecast from our early December prediction as the Atlantic Ocean remains anomalously warm and tropical Pacific sea surface temperatures have continued to cool," said Klotzbach.
As for landfall predictions, Klotzbach and Gray said probability levels were up this year over the norm. They said the probability that one Category 3-5 hurricane would make landfall:
- along the entire U.S. coastline is 81%, while the average for the last century was 52%;
- on the U.S. East Coast including the Florida Peninsula is 64%, while the average for the last century was 31%;
- Gulf Coast from the Florida Panhandle westward to Brownsville is 47%, while the average for last century is 30%.
"Even though we expect to see the current active period of Atlantic major hurricane activity to continue for another 15-20 years, it is statistically unlikely that the coming 2006-2007 hurricane seasons, or the seasons that follow, will have the number of major hurricane U.S. landfall events as we have seen in 2004-2005," said Gray.
The forecasters said that since 1949, there have been four hurricane seasons with characteristics similar to what they observed in February-March 2006 and what they project for August-September 2006. "The best analog years that we could find for the 2006 hurricane season are 1964, 1996, 1999 and 2003," they said. "We anticipate that 2006 seasonal hurricane activity will have slightly more activity than what was experienced in the average of these four years. We believe that 2006 will be a very active season in the Atlantic basin."
Klotzbach and Gray believe that neutral or weak La Niña conditions are likely to be present during August-October 2006. "When the tropical Atlantic is warm and neutral or La Nina conditions are present, Atlantic basin hurricane activity is greatly enhanced," they said. "We anticipate that ENSO [El Niño Southern Oscillation] will likely be somewhat cool and will therefore play an enhancing role for the 2006 season."
Reiterating their position on global warming's affect on hurricane activity, Klotzbach and Gray said that despite the global warming of the sea surface of about 0.5 degrees Celsius that has taken place over the last three decades, global numbers of hurricanes and their intensity have not shown increases in recent years except for the Atlantic.
The forecasters pointed out that the Atlantic has seen a very large increase in major hurricanes during the last 11-year period of 1995-2005 (average four per year) in comparison to the prior 25-year period of 1970-1994 (average 1.5 per year).
"This large increase in Atlantic major hurricanes is primarily a result of a multi-decadal increase in strength in the Atlantic Ocean thermohaline circulation (THC), which is not directly related to global temperature increase," the forecasters stated. "Changes in ocean salinity are believed to be the driving mechanism.
"No credible observational evidence is available or likely will be available in the next few decades which will be able to directly associate global surface temperature change to changes in global hurricane frequency and intensity."
Looking at the active Atlantic hurricane years of 2004 and 2005, the forecasters said "it is rare" to have two consecutive years with such a strong simultaneous combination of high amounts of major hurricane activity together with especially favorable steering flow currents.
"What made the 2004-2005 seasons so unusually destructive was the high percentage of major hurricanes that moved over the U.S. coastline," Gray said. "These landfall events were not primarily a function of the overall Atlantic basin net major hurricane numbers, but rather of the favorable broad-scale Atlantic upper-air steering currents that were present the last two seasons. It was these favorable Atlantic steering currents that caused so many of the major hurricanes to come ashore."
The forecasters said the likelihood of seeing another two consecutive hurricane seasons like 2004-2005 is very low.
The next TMP seasonal update of its 2006 Atlantic basin hurricane forecast will be released on May 31, which will coincide with the official start of the 2006 hurricane season on June 1.
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