Tuesday, October 2, 2007

Hurricane Watch: First half of October hurricane outlook

From Jeff Masters WunderBlog:

First half of October hurricane outlook

In the first half of October, Atlantic tropical cyclone activity remains high, and is in the final two weeks of its peak phase. Since the current active hurricane period began in 1995, the first half of October has given birth to an average of 1.9 named storms, 0.75 hurricanes, and 0.3 intense hurricanes. For the entire month of October, these figures are 4.2 named storms, 1.2 hurricanes, and 0.6 intense hurricanes.

These numbers are about double the long-term climatological averages for the past 100 years. The final seasonal forecast from the Phil Klotzbach/Dr. Bill Gray team at Colorado State University, issued today, calls for four named storms, two hurricanes, and one intense hurricane for the remainder of this year.

October storms form from tropical waves that come off the coast of Africa, and from the remains of old fronts that push off the coast of the U.S. As we can see from the track plot of all first half of October storms (Figure 1), there is a lot of activity during the period, but relatively few storms form out near the African coast. The water temperatures off the coast of Africa are starting to cool and be marginal for hurricane formation, and wind shear is starting to pick up in its normal fall cycle....MORE