No, slightly below normal
Posted by
prayformojo (aka mayhem)
May 30 '14, 11:51
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During an average season (using 1981-2010 as a baseline), there are 12 named storms in the Atlantic basin. Of those, 6-7 become hurricanes, and 2 become major hurricanes (Category 3-5). I acquired eight different seasonal forecasts by various agencies, and rather than listing all of them here, I will just share the consensus, which often has more skill than any particular forecast anyway. The consensus forecast I calculated is 10 named storms, 4 hurricanes, and 1 major hurricane. In terms of ACE (Accumulated Cyclone Energy), the consensus is about 80 percent of the median value (~73×10⁴ kt²).
One of the main reasons that seasonal forecasters are anticipating reduced activity is a high probability of a strong El Niño forming. Although the phase of ENSO (El Niño Southern Oscillation) is determined by the ocean and atmosphere in and over the tropical Pacific Ocean, its effects are felt around the world, including the tropical Atlantic Ocean. Thirty years ago, Dr. William Gray at Colorado State University found and documented an important relationship: when ENSO is in an El Niño (warm) phase, Atlantic hurricane activity is noticeably suppressed… when it’s in a La Niña (cool) phase, Atlantic hurricane activity is enhanced.
Published in the same paper as that now-well-known ENSO relationship, Gray also linked the QBO to Atlantic hurricane activity. The QBO, or Quasi-Biennial Oscillation, is a shift in the direction of the tropical stratospheric winds with a period of about 27 months. He found that when the winds at 30 millibars (~80,000 feet) were westerly or becoming westerly, Atlantic hurricane activity was enhanced, and when the winds were easterly or becoming easterly, activity was suppressed. As of this month, the QBO is just about to enter an easterly phase, which by itself may not be anything critical, but it’s just another signal that could make a contribution to suppressing the overall activity.
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