Late September storms may liven up hurricane season, say Colorado State University forecasters

By Erwin Seba

HOUSTON, Sept 9 (Reuters) - The latter half of September may see more tropical storms than much of this year's hurricane season so far, said forecasters from Colorado State University on Tuesday.

Since the season began on June 1, there have been only six named tropical systems, one of which was Hurricane Erin. That is less than half of the 16 named storms researchers from the CSU's Tropical Meteorology Project predicted in early August.

The researchers said a high pressure system over the Azores and high altitude troughs have pushed subtropical dry air into the tropical Atlantic, reducing conditions for storm formation.

Also, tropical waves from Africa, which can seed storms, have been weaker, further reducing the chances a cyclone is spawned.

But the weather patterns that have hindered storm development are expected to weaken by mid-September, raising the possibility for more Atlantic activity before the season ends on November 30.

The next seven to 10 days will likely remain quiet in the Atlantic, with strong vertical wind shear and moisture patterns unfavorable to tropical cyclones, the researchers said.

"However, after that point, vertical wind shear is forecast by (European forecasters) to weaken substantially, potentially yielding much more Atlantic favorable tropical cyclone conditions later this month."

CSU, in line with other forecasters, is still predicting three major hurricanes with wind speeds over 111 mph (179 kph) this season. It is expecting eight hurricanes in all out of a total of 16 named tropical storms.