Hurricane damper as tropical depression 6 forms

BRIDGETOWN, Barbados, September 4, 2006 - As if on cue Tropical Depression # 6 formed in the mid-Atlantic Ocean yesterday as forecast by computer models but it is not expected to pose any threat to the Caribbean within the foreseeable future. This comes as a new hurricane season forecast is issued reducing the number of storms expected this season.

Last week computer models had been forecasting that four cyclones would form in the Atlantic Ocean in the first 14 days of September ( See story "Wave watch" ). The first was expected to form September 3 and it did. Each cyclone is forecast to spin harmlessly into the Atlantic Ocean.

Tropical depression #6 at 5 am Eastern Standard Time today was way out into the Atlantic Ocean near 15.6 north and 41.1 west moving towards the northwest near 12 miles per hour (mph) with maximum sustained winds of 35 mph and a central minimum pressure of 1005 millibars. The system did not strengthen overnight as forecasters had expected.

The centre of the system remains poorly organised and very broad. In fact, the National Hurricane Centre in Miami, which tracks hurricanes in the Atlantic, said that there appears to be many centres within the broad area of circulation and banding features which have started to appear are not associated with the estimated centre. This fluid situation may result in the cyclone becoming organised around the dominant centre and depending on where it is located, it may give the illusion that the depression has actually jumped around. The final fix may also see a change in direction of the system.

Environmental conditions are mixed and immediate strengthening is not expected but later this week, the conditions are expected to all coalesce leading to better organisation and the formation of a tropical storm.

New forecast

The Colorado State University team of Phillip Klotzbach, who took over lead forecasting from Professor William Gray this year, has reduced the number of storms and cyclone activity for this hurricane season. In a new forecast issued at the weekend, the team now expects 13 storms, five hurricanes and two major hurricanes. The original forecast was for 19 storms, seven hurricanes, and five major hurricanes. In August it was reduced to 15 storms
, seven hurricanes, and three major hurricane.

Klotzbach said that their August only forecast was a bust in which they over-estimated the activity in August. In an average year one-third of the season's activity would have occurred by the end of August but this year just under one-fifth of the activity occurred. As a result he reduced the figures to bring it inline with the present trend.

"We now expect that the 2006 hurricane season will have slightly less hurricane activity than the long-term average. This is due to an unexpected increase in tropical Atlantic mid-level dryness (with large amounts of African dust) and a continued trend towards El Niño-like conditions in the eastern and central Pacific," he said.

Though El Nino is a Pacific Ocean phenomenon which brings drought conditions to south America, research by the US National Oceanic and Atmospheric Administration (NOAA) has shown that the conditions spread into the Caribbean by reversing the direction of the upper level winds which chop of the cloud tops when deep thunderstorms are trying to form. This in turn brings drought conditions to the Caribbean. The research by Trinidadian scientist Dr Roger Pulwarty of NOAA, who studied the impact of El Nino on the sugar industry in Trinidad and Tobago showed there is normally a lag time of three months between the emergence of El Nino in the Pacific and its impact in the Caribbean.