Hurricanes Typically Peak in Early September, But At The Moment, There Are No Active Hurricanes.


“As we reach the historical peak of the Atlantic hurricane season, there are no active hurricanes in the Atlantic or the Pacific basins. If fact, Wednesday afternoon marked the first time that we had no active hurricanes in the Atlantic or the Pacific since Aug. 26, according to Phil Klotzbach of Colorado State University and blogger for wunderground.com.“  The preceding quote is from a Weather.com posting on 10 September titled “There Are No Active Hurricanes in Atlantic or Pacific as Peak of the Season Arrives

The posting says that normally by this time, we would have had 3 hurricanes but so far we have had but one—Hurricane Danny that existed from 20-22 August.   The postings adds:” When looking at long-term averages of hurricanes and tropical storms in the Atlantic Basin, there is a broad maximum from late August through September. However, within this broader period is a peak that typically occurs around Sept. 10 or 11, depending on what data is used for the calculation.

The following chart illustrates the peak hurricane season.

peaks-by-typehuricame

The real measure of hurricane activity is called the Global Accumulated Cyclone Energy (ACE) which measures not only the hurricanes that are most familiar to us—those that originate in the Atlantic Ocean– but also the typhoons or hurricanes in the Eastern and Western Pacific, the Indian Ocean and the Southern Hemisphere. The Pacific nominally represents about 56% of the ACE and the Atlantic about, 13%.

The ACE is used to “express the activity and destructive potential of individual tropical cyclones and entire tropical cyclone seasons. ACE is calculated as the square of the wind speed every 6 hours, and is then scaled by a factor of 10,000 for usability. The ACE of a season is the sum of the ACE for each storm and takes into account the number, strength, and duration of all the tropical storms in the season.”

ACE-Global-2015

Global Accumulated Cyclone Energy (ACE) since 1970.

The chart shows that storm activity worldwide over the past 4 years is at a 45-year low and that the trend has been in steep decline since 1990. Source:Weatherunderground.com.

Although the ACE is down to date for this year, things are brewing in the Eastern Pacific, related to the major El NINO now underway. I suspect that the full year 2015 will not set any records but that it will show growth as a consequence of the EL NINO.

cbdakota

 

 

 

 

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