The group now forecasts around 16 named storms, nine hurricanes and four major Category 3 hurricanes with winds of 111 mph to 130 mph.

Nine hurricanes is one more than the eight predicted last week by the Colorado State University forecast team, which also said it foresees a higher than normal hurricane season.

TSR's forecast anticipates a year that has a high probability (77 percent) of being in the top 33 percent of all hurricane seasons in terms of activity.

The meteorologists said the anticipated active season is mainly due to forecasted trade winds in the upper levels of the atmosphere during the August to September timeframes, which enhances the ability for the atmosphere to generate tropical low pressure areas, as well as expected above-average sea surface temperatures.

April's forecast from TSR was an increase from the December 2009 forecast. It cited "anomalous warming of the waters in the Atlantic Main Development Region, a region that lies between the Cape Verde Islands and the Caribbean Lesser Antilles," as a major factor in the storm activity.

TSR said the probability of storms making landfall in the United States at an above-average level is 76 percent; the chance that it will be near normal is 18 percent and below normal is 6 percent.

The London group also said it sees the possibility of three-to-seven named tropical storms impacting the use.

It explained that the July to September trade wind speed will be influencing the spinning up of storms (cyclonic vorticity) in the main hurricane track region and the August to September main storm development region sea surface temperature provides heat and moisture to power incipient storms in that main track region.

The Colorado team predicted 15 named storms will form in the Atlantic. Eight are expected to become hurricanes, and four will develop into major hurricanes--Category 3, 4, or 5 on the Saffir-Simpson scale, with sustained winds of 111 mph or more.