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Hurricane season begins

By: Dr. Jeff Masters,

Atlantic Hurricane season officially begins today, Wednesday, June 1, and runs through November 30. This year's season is expected to continue the trend of above-normal activity seen since 1995. Both NOAA and Colorado State Professor Bill Gray's team predict a much more active than usual season. NOAA expects a 70% chance of an above-normal hurricane season, a 20% chance of a near-normal season, and only a 10% chance of a below-normal season. Long-term averages for the number of named storms and hurricanes are 10 and 6, respectively. Bill Gray's team predicts 15 named storms and 8 hurricanes, with a 77% chance of at least one major hurricane (Category 3 or higher) hitting the U.S.

Among the factors expected to cause a more active hurricane season are:

1) The absence of El Nio. According to NOAA's Climate Prediction Center, last year's weak El Nio conditions ended in April 2005, and El Nio conditions are not expected to recur during this year's hurricane season. There is a well-known link between El Nio and Atlantic hurricane activity, with El Nio favoring fewer hurricanes and La Nia favoring more hurricanes.

2) Much warmer than average sea surface temperatures (SSTs). Atlantic SSTs are at their highest in over 50 years, and are close to being the highest on record. This means plenty of high-octane "fuel" for hurricanes.



3) We are in the middle of a multi-decadal period of high Atlantic hurricane activity. Atlantic hurricane seasons have decades-long periods of generally above-normal or below-normal activity. These fluctuations are tied to a complicated set of natural cycles that occur in the winds and ocean currents over the Atlantic. Beginning with 1995 all of the Atlantic hurricane seasons have been above normal, with the exception of two El Nio years (1997 and 2002). This contrasts sharply with the generally below-normal activity observed during the previous 25-year period 1970-1994.

If you live in Florida, it's going to be tough to match last year's hurricane season, though. I compute the odds of at least four hurricances hitting Florida (3 of them major hurricanes) as happened in 2004 as a once in 300 year event. Two years back-to-back like that would happen once every 90,000 years.

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Very informative. No one leaves comments anywhere very often. Just waiting for my written weather opportunity. Good start!
While it's plain to see how the SST affects the hurricane season, does it at all affect the weather more inland? For instance, does the surface temperature cause irregular or different fronts to move across the mainland?
Yes, large areas of higher or lower than normals SSTs can affect the path of the jet stream, and lead to altered storm tracks.
Living here in Central Florida, we hear all the media outlets talking about this year's hurricane season. The impression being left is that we will be facing the same kind of year as we did last year. This is the first I have seen where the odds are put out there for a repeat. Of course, this could be year 89,999.
Has anybody, or can anybody, make a projection as to the placement of the Bermuda High?
Dr Masters; Would you buy a house anywhere near Pensacola Florida? Or anywhere else on the coast for that matter?
If you had to give an guess, where would you expect to see hurricanes coming in contact with the USA coastline?

do you think we will see more in the gulf this year or will GA and the Carolinas be seeing some action?

I know you cant say for sure, just curious as to what areas you think might see some problems this year.