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Institute for Crisis, Disaster, and Risk Management Crisis and Emergency Management Newsletter Website |
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December
2006
Volume
11 - Number 3 |
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by Chrysi Kastrioti Hurricane activity is believed to be affected by a number of factors, although it has not been scientifically proven yet, how these factors influence the intensity or the number of hurricanes each year. Recent researches indicate that there is a possible nexus between El Nino phenomenon and hurricanes. According to latest reports by NOAA’s Climate Prediction Center (1) and hurricane expert Dr Gray (2), El Nino phenomenon seems to have returned and therefore it is assumed that there might be implications for the 2007 hurricane period. In order to understand better the relationship between this phenomenon and hurricane activity, it is essential to look into the El Nino’s life cycle. Warm El Nino events occur irregularly every 2-7 years lasting 12 to 18 months, and tend to suppress hurricane activity in the Atlantic and increase it in the eastern Pacific. More specifically, ocean surface temperatures become warmer than normal in the equatorial Pacific. “This ultimately causes an adjustment to the jet stream making it more west-to-east, which keeps the cold air primarily in Canada, shifting the storm track to the southern part of US, so there are fewer storms across the north” (1). Therefore, due to the statistical and coupled model forecasts which indicate warmer conditions in the tropical Pacific through the Northern Hemisphere winter and also the latest National Center for Environmental Prediction (NCEP) climate forecast system (CFS) predictions which show El Nino conditions for the remainder of 2006 and into the Northern Hemisphere spring (SH fall) 2007, it is assumed that there is going to be a decrease in the number of hurricanes for 2007. Nevertheless, other scientists firmly believe that El Nino will not affect the next hurricane period. The fact that the winter period may be warmer than average, is not a sign that this phenomenon will reach the magnitude of the very strong 1997-1998 El Nino episode. If it remains as a moderate phenomenon then it will have no effect on the 2007 hurricane season. Bastardi’s research points out exactly this issue and adds that El Nino may weaken even more during the winter (3). Therefore, nothing seems to be definite. The near future will definitely show a clearer and more precise picture for the 2007 hurricane season. For more information: 1) “NOAA issues final forecast for 2006-2007 US winter season”, http://www.noaanews.noaa.gov/stories2006/s2742.htm, 16th November 2006 2) Philip Klotzbach and De Gray, “Summary of 2006 Atlantic tropical cyclone activity and verification of author’s seasonal and monthly forecasts”, http://hurricane.atmos.colostate.edu/Forecasts/2006/nov2006/, November 2006 3) www.accuWeather.com |