cieldumort
(Moderator)
Wed Aug 09 2017 02:26 AM
Re: 2017: 'Active Era' + Busy Season?

As of August 9, the jury is still out on whether or not 2017 will be considered part of the 'Active Era,' but there is definitely greater confidence in it being a busy season.


First, as for the Active Era question, Phil Klotzbach notes the 'AMO using @ColoradoStateU definition was -0.9 standard deviations in July.'

As can be seen in the image below, the index has been somewhat negative for much of the last three and a half years, and trending back down again lately. I have taken the liberty to draw lines across the +1 and -1 standard deviations, which is visually even more compelling that the AMO may in fact be trending negative (Subdued phase).. although, still maybe not there just yet.



As mentioned in earlier entries, one of the reasons for this being an 'active season' might be the anomalously favorable Main Development Region, overall. As the name implies, it is considered the Main Development Region. However, it is worth pointing out that the MDR is also running higher-than-normal sea level pressures (anomalously unfavorable), possibly in response to a developing negative phase of the AMO discussed above.

Atlantic Tropical Cyclone count year-to-date is still running hot for named storms, with only four other seasons having six of their own by the date Franklin formed: (1936, 1959, 2005 and 2012. - Cr. Philip Klotzbach). But how many seasons prior to, oh, 1990 even, could have easily had as many, if they enjoyed the same advances in observations that we do today. Probably at least as many more, so 2017 isn't running all *that* hot. Not yet, anyway.

But we are in the peak months now (Aug-Sep-Oct), where the rubber usually hits the road in the Atlantic basin, and looking ahead to the remainder of this month, we may continue to see an active August for at least another two weeks, if forecast large scale patterns verify.

Franklin, now. Next up, Gert. 99L is already looking much better tonight. Our 'G' storm may be right around the corner.



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