Ed Dunham
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| (Former Meteorologist & CFHC Forum Moderator (Ed Passed Away on May 14, 2017)) |
| Thu Aug 12 2010 06:45 PM |
Re: Too soon?
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Well it was certainly an interesting article, but I’m having some trouble following his logic. Dr Klotzbach assumes a high ACE value this season and he forecasts a very high total of 18 named storms (which could give you a high ACE value). However, if the assumption is incorrect then the forecast is in trouble. He shows a table of all of the La Nina years since 1950 along with the date of the second hurricane for those 16 seasons. The first 4 dates in the table (and probably the 5th) are already history as far as this season goes. But ignoring that, the average storm totals for all of the years that he lists are 12/7/4. What that tells me is that on average, during a La Nina year, you are going to get 12 named storms – the August forecast, just recently issued, was 18 - which certainly implies a well above average season.
Only three of the years with the greatest number of named storms are in his table – 1995, 1998 and 2007. That tells me that La Nina years are not good years for high storm activity, since the other 13 high-activity years must have been ENSO neutral or El Nino years (a few years ago Ostro & Lyons – TWC - actually document that this is indeed the case). Unfortunately he used the two recently active areas with a high expectation for development (TD5 and Invest 93L) in his article – but neither of them made it to TS status. He also uses 1961 as an example of a season with a second hurricane in September (which is fine), but the season totals for 1961 were 11/8/7, which is a normal seasonal total. When you forecast a seasonal total of 18 named storms, tropical storms usually play a significant role in reaching that total, but the article concentrates on the date of the second named hurricane.
Dr Klotzbach states that “from a climatological perspective, it is not time to write off the TC season yet†and I certainly agree with him on that point. So far, the tropical cyclone season is certainly not a ‘bust’ – the season still has a long way to go - but a high-activity season (16 or more) will soon be very difficult to achieve.
ED