By: Jeff Johnson, chief science officer and certified consulting meteorologist

Telvent DTN's outlook for the 2010 tropical weather season calls for an increasingly active year with an above average number of storms in the Atlantic Basin. During an average season there would be 10 to 11 named storms (tropical storms or hurricanes) - six of these would reach hurricane intensity, and two to three would be classified as major hurricanes reaching category three or higher. 

Two of the primary factors that influence how active a tropical season becomes are: 1) the ocean surface temperatures in the tropical area and, 2) the amount of wind shear that is present through a large depth of the atmosphere. Warm water helps to fuel the thunderstorms that grow and merge into the initial disturbance. Weak wind shear allows these thunderstorms to grow and form a circulation center in the low levels with good outflow in the upper areas.

Currently the environment is somewhat hostile for both of these factors in the Gulf of Mexico, eastward into the central Atlantic, as very warm water and lower than normal windshear exists in the Caribbean and southern Atlantic.

This pattern might favor more early season development in the Caribbean and southern Atlantic with a reduced threat closer to the U.S. Later this summer, and especially this fall, as the gulf waters warm closer to normal and a developing La Nina reduces the windshear, we expect the threat of storms will increase. By the time the season ends, higher than normal storm totals are expected with a greater than normal threat for the U.S. mainland.

In summary, our expectations are for a quiet start to the season, with an increase in storms in the middle and latter portions of the season. The La Nina continuing through the fall could extend the season well into November in 2010.