2009 Updated Atlantic Hurricane Season Outlook: Summary
NOAA’s updated 2009 Atlantic Hurricane Season Outlook indicates a 90% chance of a near-normal or below normal hurricane season. These seasons are classified using the ACE index, which accounts for the combined intensity and duration of the total named storms and hurricanes, and NOT by the numbers of named storms and hurricanes. The Atlantic hurricane region includes the North Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico.
This outlook reflects two competing climate factors. The ongoing multi-decadal signal remains in place and has been associated with elevated levels of Atlantic hurricane activity since 1995, along with warmer than average sea surface temperatures (SSTs) in the tropical North Atlantic Ocean and Caribbean Sea. Offsetting this signal is El Niño, which developed in the tropical Pacific Ocean during June and is already producing increased wind shear in the Main hurricane Development Region (MDR, consisting of the tropical North Atlantic Ocean and Caribbean Sea).
