2007 Atlantic Hurricane Season Outlook
The U.S. National Oceanic and Atmospheric Administration (NOAA), released its outlook today for the 2007 Atlantic hurricane season, which begins June 1 to November 30. NOAA is projecting a total of 13 to 17 named storms of which 7 to 10 will intensify to hurricanes, including 3 to 5 becoming major hurricanes - rated at Category 3 or higher.
This forecast is consistent with the outlooks issued by Colorado State University in early April and by the Tropical Storm Risk Consortium in early May.
|Forecast Source||Forecst Date||Tropical Storms||Hurricanes||Major Hurricanes|
|NOAA1||May 22||13 - 17||7-10||3-5|
|TSR3||May 3||12.3 - 19.9||6.3 - 11.5||2.5 - 5.5|
- National Ocean and Atmospheric Administration
- Colorado State University Tropical Meterology Project (PDF)
- Tropical Storm Risk, Benfield Hazard Institute (University College London)
For detailed information on what’s behind each of these outlooks, click on the hyperlinks above.
The 2006 hurricane season was quieter than had been predicted because an unexpected El Niño dominated through the height of hurricane-development months. This El Niño ceased rapidly in March of this year. Accordingly, there are no anticipated large-scale effects that should inhibit Atlantic hurricane production in 2007.
What's behind the outlook?
According to NOAA, the prediction for an above-normal 2007 hurricane season reflects the expected combination of two main climate factors: 1) the continuation of conditions that have been conducive to above-normal Atlantic hurricane seasons since 1995, and 2) the strong likelihood of either El Niño-neutral or La Niña conditions in the tropical Pacific Ocean.
The Colorado State University April forecast was based on three predictors using only February and March data...
- Sea surface temperatures in the subtropical eastern Atlantic and in the South Atlantic;
- The sea level pressures in the subtropical southeastern Pacific. The six closest matching historical years were found;
- The seasonal hurricane activity was assessed in order to make a prediction for 2007.
The Tropical Storm Risk group uses a different approach. Rather than looking backwards for data they make predictions of the upcoming late summertime conditions of two key parameters:
- the trade wind speed over the Caribbean,
- tropical Atlantic and the sea surface temperatures in the tropical Atlantic.
Both trade wind speed and sea surface temperatures are well-correlated factors in hurricane development.
What does this mean for Canada?
The science of hurricane forecasting has not evolved enough to accurately predict when and where these storms will move or make landfall months in advance. The details of the large-scale weather patterns that direct the path of hurricanes cannot be predicted more than a few days in the future.
Over the years, 37 percent, or roughly one-third, of the tropical storms forming in the Atlantic threaten Canada or her waters in some way. This type of statistic is of little use on a yearly basis because of the variability from year to year. For example, over the last 30 years, the percentage of tropical cyclones that reach our areas has ranged from as low as 14 percent in 1987, to 60 per cent last year.
There is no clear correlation between the number of tropical storms or hurricanes in the Atlantic and the number that threaten Canada. As well, there is no trend in the percentages of Atlantic tropical storms that reach our areas. Therefore, while tropical cyclone activity may be high in the Atlantic this year, there is little information available to tell us what we can expect in Canada. Regardless, we approach the hurricane season with the same message each year...to be aware and be prepared. The prevention of the loss of life and property from tropical cyclones is a responsibility shared by all of us. As a reminder of our lessons learned from Hurricane Juan in 2003, it only takes one hurricane hitting in your community to make it a bad season.
Accordingly, the Canadian Hurricane Centre (CHC) continues watching over the Atlantic year round for any tropical cyclones that may form and threaten Canada or her waters. The hurricane season officially runs from June through November when the waters of the Atlantic are warm enough to produce tropical cyclones, however, tropical cyclones can occur in any month of the year.
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