NAO and hurricanes

I'm a real weather n00b. But, I still find weather fascinating.

So, I pose a question:
Does the weakend NAO (north atlanitc oscillation) play into the numerous hurricanes? Could it cause more severe hurricanes? Would it cause hurricanes after the normal "season" is over?

The NAO has only a small correlation with overall U.S. hurricane landfall probabilities, but it appears to influence strongly which regions in the United States are most likely to experience hurricane landfall (Figure 2). Strongly positive NAO values are associated with high intense hurricane landfall probabilities along the East Coast. Strong negative NAO values are associated with high intense hurricane landfall probabilities along the Gulf Coast.

www.bbsr.edu...

The NAO influences landfall probability for Atlantic hurricanes through changes in the above-mentioned subtropical high-pressure cell over the Atlantic Ocean. A positive NAO index is correlated with elevated pressures in the subtropical high over the North Atlantic Ocean and more frequent re-curvature of Atlantic hurricanes. A negative NAO index is correlated with lower pressures in the subtropical high and a more zonal atmospheric flow that tends to maintain an east-to-west hurricane track.

www.bbsr.edu...


more about NAO
www.eurekalert.org...
www.nasa.gov...

discussion of hurricanes and NAO interaction (all are PDF)
garnet.fsu.edu...='NAO%20hurricanes
coastal.er.usgs.gov...='NAO%20hurricanes
www.aoml.noaa.gov...&Mestas_2003.pdf#search='NAO%20hurricanes

I'm one of those weather watchers who doesn't believe in global warming per se. I believe the current trends are more likely part of a larger climatic event that has been going on as long as the planet earth has existed.

So, wha do you all think?




[edit on 2-1-2006 by DontTreadOnMe]

In brief, yes it would influence it to some extent. There's a lot of other factors to forming hurricanes (as I understand it), but it can "steer" them to warmer or colder waters (enhancing them or causing them to die off) depending on where it is and what it's doing.

Of more significance to hurricane formation is the Atlantic Multidecadal Oscilliation - which is currently in its active, warm, phase. This basically means warmer water in the Atlantic which is what hurricanes need to form.

In addition, there is currently a weak La Nina in the Pacific. Although this itself doesn't affect hurricane formation, the opposite phase (El Nino) does help to inhibit hurricane development.

So, a warm phase of the AMO and no El Nino = lots and lots of huirricanes.....

More info on the AMO

Thanks for the added information.
It seems to me too many jump on the global warming bandwagon when it is more likely that natural conditions in certain combinations are the real culprit.

In the book Catastrophe, by David Keys, the author states that after the catastrophe around 535 AD, there were devastating drought and flood conditions in Mexico and the SE US. It was in part due to El Nino.

Thanks for the information, Essan. Really interesting.

Do you know when scientist became aware of the AMO, when did they discover and publish it?

Thank you.

Oceanography is a very new science. The Atlantic Multidecadal Oscillation was only described for the first time by R A Kerr in 2000 (A North Atlantic climate pacemaker for the centuries: Science, 288: pages 1984-1986) But there was evidence of long term variations in Atlantic sea surface temperatures, and corresponding effects on local climate, before then. In the past few years its been subject to a great deal of scrutiny though.