Aon predicts 2008 will be even warmer than 2007

The first half of 2008 will likely bring warmer weather in southern Canada and increased storm activity in the southern United States, Aon’s Annual Global Climate and Catastrophe Report: 2007 says.

The period between January and May 2008 will mainly be influenced by the El Nino/Southern Oscillation, which is an anomalous warming or cooling of the central Pacific Ocean waters that generally occurs every three to seven years, the report explains.

The polar jet stream — the jet stream responsible for Arctic outbreaks — will likely be pushed northward, keeping cold Arctic air across the northern portions of Canada, the report says. That will mean warmer-than- normal temperatures to the rest of the country and northern United States.

The subtropical jet stream, which usually sinks southward during the winter months, will drift northward and bring a succession of storm systems across the southern tier of the United States, it adds.

The report also summarized the 2008 Atlantic Hurricane Season forecast by Colorado State University, but noted a major factor was not considered in the forecast. The Colorado forecast, Aon notes, does not take into account the amount of dry air and dust that moves from the Sahara Desert in Africa into the central Atlantic Ocean over an area known as the Main Development Region (MDR).

“This factor makes development of tropical thunderstorms, the key ingredient for the formation of a tropical storm or hurricane, very difficult,” the report says.

“This is the factor that led to the comparatively-benign seasons of 2006 and 2007. Forecasting dry air and dust outbreaks across the MDR is very difficult at best and is only accurate one to two weeks in advance at this time.” •