We expect that the next two weeks will be characterized by above-average amounts of activity (greater than 130 percent of climatology.)
So starts the latest two week forecast from Philip Klotzbach and William Gray at Colorado State University.
As you can see in the graphic, the most intense part of the hurricane season should be behind us, and 130% of “climatology” means we can expect less activity than we had in September. (Note that they are talking about ACE – Accumulated Cyclone Energy, the sum of the squares of the estimated wind speed at each 6 hour report by the National Hurricane Center.
The graph above is just the number of storms observed on the date over 100 years.) They base their prediction “primarily to the heightened amount of activity being called for by most of the global models.” This includes both tropical depression 16 which may bring tropical storm force winds to Cuba, Florida, and North Carolina, and one or two more systems predicted by some models.
That’s about it for this forecast.
Storm development this time of year shifts from the Cape Verde area to the Caribbean. As such, the number of long-lived intense storms declines quickly. On the other hand, storms that form in the Caribbean don’t have the room to recurve away from the US mainland as the Cape Verde hurricanes often do, and hence have a better chance of landfall somewhere. Don’t let down your guard.
The forecast for the previous two weeks verified quite well, as Igor, Julia and Karl were existed at the start of the period. Klozbach and Gray only choose one of three broad ranges in these forecasts, and the forecast of 130% or more was readily exceeded – about 220% of climatology was recorded. Not a very hard forecast when you have two Cat 4 storms around.
For an interesting counterpoint, see Joe Bastardi’s video The Reason for the Season and Why I Wasn’t Teasin’. He puts forth his case why he expects the Caribbean to be the focus of hurricane development and why he thinks that
“The US may still have the worst part of the season, as far as impact goes, ahead of us.”
I don’t agree with (or is it I don’t understand?) everything he says, but he has an engaging style and offers some good insights.