NOAA Predicts Very Active 2006 Hurricane Season
Residents in hurricane prone areas urged to make preparations.

T he National Oceanic and Atmospheric Administration (NOAA) warns that a very active hurricane season is looming and encouraged individuals to make preparations to better protect their lives and livelihoods.

    “For the 2006 north Atlantic hurricane season, NOAA is predicting 13 to 16 named storms, with eight to 10 becoming hurricanes, of which four to six could become ‘major’ hurricanes of Category 3 strength or higher,” stated retired Navy Vice Admiral Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator.

    On average, the north Atlantic hurricane season produces 11 named storms with six becoming hurricanes, including two major hurricanes. In 2005, the Atlantic hurricane season contained a record 28 storms including 15 hurricanes. Seven of these hurricanes were considered major, of which a record four hit the United States. “Although NOAA is not forecasting a repeat of last year’s season, the potential for hurricanes striking the U.S. is high,” added Lautenbacher.

    During a news conference at the NOAA National Hurricane Center, Deputy Secretary of Commerce David A. Sampson noted, “Preparation is the key message . . . The impact from these storms extends well beyond coastal areas so it is vital that residents in hurricane-prone areas get ready in advance of the hurricane season.”

    “Whether we face an active hurricane season, like this year, or a below-normal season, the crucial message for every person is the same: prepare, prepare, prepare,” said Max Mayfield, director of the NOAA National Hurricane Center. “One hurricane hitting where you live is enough to make it a bad season.”

CONFLUENCE OF CONDITIONS

    Warmer ocean water combined with lower wind shear, weaker easterly trade winds and a more favorable wind pattern in the mid-levels of the atmosphere are the factors that collectively will favor the development of storms in greater numbers and to greater intensity. Warm water is the energy source for storms while favorable wind patterns limit the wind shear that can tear apart a storm’s building cloud structure.

    This confluence of conditions in the ocean and atmosphere is strongly related to a climate pattern known as the multi-decadal signal, which has been in place since 1995. Since then, nine of the last 11 hurricane seasons have been above normal with only two below-normal seasons during the El Niño years of 1997 and 2002.

    With neutral El Niño/Southern Oscillation conditions expected across the equatorial Pacific during the next three to six months, the NOAA Climate Prediction Center scientists say that neither El Niño nor La Niña likely will be a factor in this year’s hurricane season.

    The north Atlantic hurricane seasonal outlook is a product of NOAA’s Climate Prediction Center, National Hurricane Center and Hurricane Research Division. The NOAA National Hurricane Center has hurricane forecasting responsibilities for the north Atlantic as well as the east Pacific regions.

Greenhouse gas may contribute to developing hurricanes, noaa study says
The region of the tropical Atlantic where many hurricanes originate has warmed by several tenths of a degree Celsius over the 20th century, and new climate model simulations suggest that human activity, such as increasing greenhouse gas emissions into the atmosphere, may contribute significantly to this warming.

    This new finding is one of several conclusions reported in a study by scientists at NOAA’s Geophysical Fluid Dynamics Laboratory (GFDL), Princeton, NJ, and published in the Journal of Climate.

    “This very long-term increase in temperature may seem small, but is comparable in magnitude to shorter time-scale, multi-decadal changes that many scientists now believe contribute strongly to an increase in hurricane activity in the Atlantic,” said Thomas Knutson, lead author of the paper and a senior research meteorologist at GFDL. “The challenge is to understand the relative roles of anthropogenic and natural factors in producing these temperature changes—and this study is a step in that direction—and then to determine whether and how these long-term changes in temperature could be affecting Atlantic hurricane activity.”

    The region, which extends from 10°N to 20°N in the area of the Cape Verde Islands, has been identified as the origin for a large portion of major hurricanes in the tropical north Atlantic and is known as the Main Development Region. Ocean surface temperatures in this region warmed over the 20th century, roughly tracking the global mean, or average, but this region has greater multi-decadal variability than the global mean does when looking at long-term trends.

    The climate model simulations are based on a new state-of-the-art coupled atmosphere-ocean model developed over several years at GFDL. The new simulations include improved representations of a number of environmental factors that can affect climate such as greenhouse gases, volcanic eruptions, solar variability, land-use changes and atmospheric aerosols, very fine particulate matter in the air. The results suggest that the century-scale warming tendency in the Main Development Region may have been caused largely by anthropogenic forcing, including increases in atmospheric greenhouse gas concentrations.

    Atlantic hurricane variability and its causes is the subject of intensive scientific investigations. Earlier studies suggest that warmer tropical sea surface temperatures can lead to hurricanes of greater intensity. Other studies at NOAA have concluded that warmer sea surfaces is one of several important factors affecting Atlantic hurricane activity. Ongoing research continues to address uncertainties in the observed trend, past climate forcing estimates, internal variability and climate sensitivity.

There will never be another katrina
The World Meteorological Organization has permanently retired the name Katrina, along with four others from the historic 2005 Atlantic hurricane season, from its revolving list of storm names.

    During its annual meeting in San Juan, Puerto Rico, in April, Dennis, Katrina, Rita, Stan and Wilma were removed from the list of potential storm names that is otherwise recycled every six years. These storms represent the type of devastating storm whose name will not be used again for sensitivity reasons for causing a large loss of life and property and to establish distinction within the scientific and legal communities.

    For 2011, Dennis, Katrina, Rita, Stan and Wilma have been replaced with Don, Katia, Rina, Sean and Whitney, respectively.
    Since tropical cyclones were first named in 1953, 67 names have been retired (the first being Carol and Hazel in 1954), and with a total of five, 2005 has the most retired storm names in a single season (the previous record was four in 1955, 1995 and 2004).