Atlantic hurricane activity expected to be above average for next two weeks

Colorado State University Department of Atmospheric Sciences has issued its latest two-week forecast for hurricane activity in the Atlantic. They predict an active period in the fortnight to come. One reason for this is the way they calculate activity using their Accumulated Cyclone Energy (ACE) index to denote activity levels. They say that Katia, which has currently slipped back to tropical storm status, should accumulate a lot of ACE on its path westward.

As well as Katia, the forecast suggests that tropical depression 13 in the Gulf of Mexico will intensify. This matches the National Hurricane Centre forecast which suggests that TD 13 will become tropical storm Lee later today and take aim for the Louisiana coastline. By the time it reaches land the NHC predict that tropical storm Lee will be close to hurricane status with winds of at least 60mph. This storm has forced the shutdown and evacuation of a number of oil platforms owned by Exxon Mobil, BP and Shell. By the time it makes landfall tropical storm Lee is not expected to cause too much wind damage but could cause significant flooding. It’s also expected to be slow moving as it comes ashore meaning that rainfall could impact some areas for many hours.

Tropical depression 13 (or tropical storm Lee) forecast path

Hurricane Katia lost some of her power yesterday and was downgraded to tropical storm Katia again. She is still forecast to move westward slowly over warmer waters and regain hurricane status tomorrow, before strengthening into a major category 3 storm. Her destination is still uncertain and some forecast models still show Katia aiming for the U.S. east coast.

Tropical storm Katia (or hurricane Katia) forecast path

There is also another disturbance in the more northerly Atlantic, about 450 miles south of Nova Scotia, which the NHC says has a 60% chance of becoming a tropical storm in the next 48 hours, so it is entirely possible that we see a tropical storm named Maria in the next few days as well. If this forms it is is forecast to head east where it should do no harm, however, storms that form in this area have been known to recurve and head back west towards the U.S. so it does deserve watching.

The forecast from Colorado State also predicts further activity in the far eastern Atlantic with several global models predicting additional development there in the next 7 to 10 days.

You can access the forecast document in PDF format here.

Keep up to date with the 2011 Atlantic Hurricane Season.