Are we still in a an active hurricane cycle

[wjs3]

Yes, SST's are the main determining factor in whether we are in an "active" cycle or not. Note that we can have above average SST's but below normal activity. But relative to the climatological record, an active cycle tends to have higher total season ACE each season compared to quiet cycle seasons.

Also, I've noticed that La Nina seasons tend to have late starts, but explosive endings.

Any data on your La Nina point? It's very interesting!

WJS3

[Extremeweatherguy]

According to what I have heard, active cycles tend to last 20-30 years. Based on that information, I do not see this cycle ending until around 2015-2025.

From a 2005 article by NOAA:

surface temperatures and low wind shear, enhance hurricane activity. This increase in the number and intensity of tropical storms and hurricanes can span multiple decades (approximately 20 to 30 years). NOAA will make its official 2006 season forecast in May, prior to the June 1st start to the season.

http://www.noaanews.noaa.gov/stories2005/s2540.htm

[boca]

I want to thank everyone for your take on this because I had no idea of what exactly determines the factors behind this cycle.

[wxmann_91]

Yes, SST's are the main determining factor in whether we are in an "active" cycle or not. Note that we can have above average SST's but below normal activity. But relative to the climatological record, an active cycle tends to have higher total season ACE each season compared to quiet cycle seasons.

Also, I've noticed that La Nina seasons tend to have late starts, but explosive endings.

Any data on your La Nina point? It's very interesting!

WJS3

The correlation is best evidenced in +AMO (active cycle) years, so the sample size is really small, but examples:

(note that these are hurricane season that precede the Nina winter, and Nina criteria is per MEI)
1998 [Alex formed on July 27]
1999 [after Arlene, Bret formed on August 18]
2000 [Alberto formed on August 3]

exceptions would be 1995 and 2005, but they were marginal Nina years; the MEI in 95-96 only dipped below -0.5 JAN & FEB, the MEI in 05-06 only dipped below -0.5 DEC and then again in spring 2006.

85 (slightly negative AMO year) was relatively normal early with two NS's in July, but during the neutral to slightly positive AMO year 1988, the first storm formed on Aug 5.

73, 74 and 75 (73-74 was the strongest Nina recorded I think) didn't fit this at all but -AMO years tend to have more non-tropical related formations, and in fact the first three storms of 74 were subtropical and Amy/Blanche of 75 I'd suspect were from non-tropical origins, given their formation areas. 73 had one STS and one that could or could not have come from tropical origin.

Note: edited for post clarity
Last paragraph edited as it was 73-74 that was the strongest

[Steve]

>>From a 2005 article by NOAA:

You must have missed my post.

[Extremeweatherguy]

>>From a 2005 article by NOAA:

You must have missed my post.

lol. you're right. I didn't take the time to read through all of the first page like I should have and completely missed your post. sorry about that.

[Cryomaniac]

My (pretty irrelevant, lets be honest) opinion is that we really don't have enough data to say say what these cycles are with any accuracy. Until there is accurate data for 500+ years it will be hard to tell.

[Category 5]

Also, I've noticed that La Nina seasons tend to have late starts, but explosive endings.

Perfect example, 1999,

[wxman57]

There seems to be a bit of confusion as to what is meant by the term "active cycle". It refers to the warm phase of the Atlantic Multidecadal Oscillation (AMO). I put together a web page describing the cycle and possible impacts around 2001:

http://myweb.cableone.net/nolasue/Florida/

Warm phases of the AMO appear to last between 25-45 years. The last warm-phase AMO was from 1926-1969 (44 years). Cool phases of the AMO appear to last a bit less (20-30 years). The term "active" does not mean that there are more named storms during these warm cycles. But with warmer SSTs, there tends to be more MAJOR hurricanes during an active cycle. During a cool cycle, we've seen an average of 1.5-2 major hurricanes per season. During an active (warm) cycle, the average number of major hurricanes per season jumps to 4-5. But in all my studies, I haven't noticed any significant difference in the number of named storms from cool to warm cycles. So as we get deeper into this active cycle, I expect the number of named storms to drop, probably close to the 50-year average of about 12 (accounting for about 3 missed storms per season prior to satellite data as suggested by Landsea/Pielke).

And, as you can see on the web page above, Florida appears to be at particularly high risk of a major landfalling hurricane during the warm phase of the AMO. Active doesn't mean MORE named storms, just a higher percentage of them being hurricanes and particularly major hurricanes. The current warm-phase AMO may well last another 20-30 years.

[flwxwatcher]

Ouch.!!!
Thanks for all that info wxman57..

[Agua]

My (pretty irrelevant, lets be honest) opinion is that we really don't have enough data to say say what these cycles are with any accuracy. Until there is accurate data for 500+ years it will be hard to tell.

Exactly.

[terstorm1012]

I just read a paper in Nature (found via Dr. Peilke's site, which is down for some reason) that suggests there are proxy reconstructions going back 5,000 years (for the Atlantic.) The paper is titled "Intense Hurricane Activity over the past 5,000 Years controlled by El Nino and the West African Monsoon."

I am also interested in http://www.sce.lsu.edu/faculty/liu.htm this guy's work.

thanks for the link i've bookmarked your site, wxman_57.