Study about strong TC's forming more away from MDR

[cycloneye]

Here is a very interesting study made by the Wisconsin University folks with colaboration from NOAA people about the trend of the past years of the MDR being less active and the subtropics turning more active. What do our Pro Mets think of this?

http://www.news.wisc.edu/22857

[Alyono]

There is a simpler explanation for this

NHC is naming more high latitude systems than they did previously.

[WeatherEmperor]

Luis,

Do you have any data for what the steering patterns look like for this year ? The last few years there was a persistent east coast trof. I was wondering if a similar pattern is predicted for this year...

Sent from my HTC EVO 4G LTE

[orion]

Should be an interesting read... I'll comment more on Monday from campus where I can access the full article. I'm curious to see if there was an across the board shift for all cyclones, or was it more pronounced at different intensity levels - such as the amount of shift of non-major as compared to major cyclones. Also, would be interesting to see if they broke the data down into different basins - does the amount of poleward shift in Atlantic cyclones significantly differ from Pacific cyclones? For climate studies, 30 years is about the minimum time period... so as they state more research is needed to see if their data is related to an expansion of the tropics, and also if factors - such as that mentioned by Alyono in a previous post - have been taken into account.

[NDG]

It seems like behind every study now days you see this included:

From a global climate perspective, Kossin says, “the more compelling aspect is that the rate of migration fits very well into independent estimates of the observed expansion of the tropics.” That phenomenon has been widely studied by other scientists and is attributed, in part, to increasing greenhouse gases, stratospheric ozone depletion, and particulate pollution, all by-products of human activity.

Whether the observed movement of tropical cyclone maximum intensity toward the poles is a result of the expansion of the tropics and its links to human activity requires more and longer-term investigation, says Kossin. Both phenomena, however, exhibit very similar behavior over the past 30 years, lending credence to the idea that the two are linked.

How can they come to a conclusion that this is the trend with only 30 years of information.
One thing that I have always said is that the tropics in the open Ocean goes beyond the 23.5 deg latitude, good example is Bermuda.

[Alyono]

Because either they do not accept that NHC is naming far more things, or they have an agenda

[orion]

How can they come to a conclusion that this is the trend with only 30 years of information.
One thing that I have always said is that the tropics in the open Ocean goes beyond the 23.5 deg latitude, good example is Bermuda.

You are correct, in tropical meteorology we usually don't define the tropics as between the tropic of Cancer and tropic of Capricorn. It is often defined by geographic location with 30N to 30S considered the tropics (and 10N to 10S considered the deep tropics) based on the meridional extent of the Hadley cells. It is also occasionally defined as where the net solar radiation is positive - which brings it up even further to almost 40 degrees latitude.

[RL3AO]

I'm highly skeptical of anyone trying to connect this to climate change for the exact reason Alonyo mentioned.

[MGC]

Agenda driven no doubt. Every report you see today has climate change woven into it. Since there has not been a huge increase in the number of intense hurricanes like Al Gore warned us of, there has to be another threat connected to the emission of CO2. Next thing there will be hurricanes forming in the Artic Ocean if you listen to the alarmist. I just roll my eyes when I hear of the latest Chicken Little the sky is falling from the alarmist.....MGC

[galaxy401]

I remember 2012 had storms struggle to intensify in the MDR but became hurricanes in the subtropics. I'm not buying into the global warming claim at all.

[Hammy]

I think they're jumping their guns personally, especially with the hurricane reanalysis ongoing. Any increase in systems outside of the tropics will likely be rendered void once they get into the 60s/70s and more nothern-forming storms likely begin showing up that were previously unclassified.

[AJC3]

The title of this thread is misleading and needs to be changed.

First, the study that Kossin et. al undertook isn't about TC "formation" occurring away from the MDR, but the point at which TCs reach their maximum intensity.

Second, the study looked at and found "global" trends using all NHEM and SHEM basins (NATL, ENP, WNP, NIO, SIO and SPAC).

Third, according to a summation of the study...

"The amount of poleward migration varies by region. The greatest migration is found in the northern and southern Pacific and South Indian Oceans; there is no evidence that the peak intensity of Atlantic hurricanes has migrated poleward in the past 30 years."

For all of these reasons, the explanation about NHC naming more systems accounting for a portion this poleward trend in max intensity really doesn't hold water.

I would suggest a title something along the lines of: "Study shows TC's reaching their maximum intensity farther away (or more poleward) from the tropics (or MDR)"

[Hybridstorm_November2001]

In light of the ongoing reanalysis project, I do wonder how reliable the data is they are using to establish evidence for such a trend. Just some food for thought my friends.