Hurricane season officially began June 1 and we have already had two named storms. The activity earlier in the season did not have any real impact, so you might have even forgotten those storms occurred. The next named storm in the Atlantic will be Chantal.
The Atlantic remains quiet, but this should not lull anyone into a false sense of comfort. On average 80% of the hurricanes that will occur in any given season would still form in the post-August 15 timeframe. Take a look at the chart below, which shows the peak of hurricane season is right around September 10. Notice a tremendous ramp-up and a rapid ramp-down in activity around mid-September.
Hurricanes form and feed on warm ocean water. The oceans take much longer to heat than the land. By the time the average temperatures have been falling in our area, hurricane season is still just coming alive with the ocean waters at their maximum warmth and potential energy.
One of the things that suppresses hurricane activity is an El Nino condition. This is because when El Nino is present the winds tend to be stronger around the equatorial belt east of South America. These winds can prevent hurricanes from becoming organized. El Nino has officially been declared over by the National Weather Service, so the dampening effect is also over.
Since conditions have returned to a neutral state across the Pacific, this can now yield a more active season here by the Atlantic.
As a result, forecasters report an increased chance that we will see an above-average year in terms of number of storms. The revised outlook, which was issued last week, has an 80% chance that this year will be normal or above normal in terms of named storms.
Although the amount of activity so far has been slim across the Atlantic Basin, globally the amount of energy produced by all tropical systems is actually slightly above average. The reason I mention this is because it’s important not to focus on just one area of the globe when it comes to any of these meteorological variables. Scientists use an index called the ACE index (Accumulated Cyclone Energy) to measure the amount of energy put out by tropical systems. You can see from the chart below that some areas of the oceans have had more energy than usual while others have had significantly less, all of it balancing out.
So while we may not see any activity in the next week or two, I am highly confident that there are plenty of tropical systems to be tracked this year. Additionally, as I always mention whenever I write about hurricanes, New England has not seen a hurricane reach our shores since Bob in 1991. We remain way overdue.