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A Record Quiet Start To The 2010 Tropical Cyclone Season In The Northern Hemisphere

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http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1575

A record quiet start to the 2010 tropical cyclone season in the Northern Hemisphere

What is really odd about this year, though, is the lack of tropical cyclone activity across the entire Northern Hemisphere. Usually, if one ocean basin is experiencing a quiet season, one of the other ocean basins is going bonkers. That is not the case this year. Over in the Eastern Pacific, there have been five named storms and two hurricanes. The average is seven named storms and four hurricanes for this point in the season. This year's quiet season is not too surprising, since there is a moderate La Niña event underway, and La Niña conditions usually supresses Eastern Pacific hurricane activity. But over in the Western Pacific, which usually generates more tropical cyclones than any ocean basin on Earth, it has been a near-record quiet season. Just four named storms have occurred in the West Pacific this year, and the average for this date is eleven. Only one typhoon season has had fewer named storms this late in the season--1998, with just three. The total number of named storms in the Northern Hemisphere thus far this year is fifteen, which is the fewest since reliable records began in 1948. Second place belongs to 1983 and 1957, with eighteen named storms. According to an email I received from NOAA hurricane researcher Gabe Vecchi, the lack of tropical cyclones so far this year in the Northern Hemisphere is between a 1-in-80 and 1-in-100 year event.

So, what is causing this quiet tropical cyclone season? One possibility is that since Northern Hemisphere land areas have heated up to record temperatures this summer, this has created strong rising motion over the continents. This rising motion must be compensated by strong sinking motion over the adjacent oceans in order to conserve mass. Sinking air causes drying and an increase in stability. Another possibility is that the unusual jet stream configuration that is responsible for the Russia heat wave and record flooding in Pakistan is also bringing dry, stable air to the Northern Hemisphere's tropical cyclone breeding grounds. It is also possible that climate change is causing the reduction in tropical cyclone activity, for a variety of complex reasons. Computer simulations of a future warmer climate generally show a reduction in global number of tropical cyclones (though the strongest storms get stronger), and it is possible we are seeing a preview of that future climate. Or, this year's quietness may simply be natural variability. It will be interesting to see when the Russian heat wave breaks if vertical instability over the Atlantic increases back to normal levels. Current forecasts from the GFS and ECMWF models project the Russian heat wave to break late next week.

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I think Dr Masters's blog is of the most consistently helpful and insightful on the net wrt all things meteorology and climate, this post is no different.

Perhaps he could provide a link to this

"possibility is that since Northern Hemisphere land areas have heated up to record temperatures this summer"

Another nail in the coffin to you know what.

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It seems that if descending air is the 'stopper' then it is allowing the Atlantic to gain even more heat (or not lose heat by 'canes stirring up the surface layer).

How will our warm Atlantic and super warm Arctic Ocean influence the latter part of the 'cane season?

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It seems that if descending air is the 'stopper' then it is allowing the Atlantic to gain even more heat (or not lose heat by 'canes stirring up the surface layer).

How will our warm Atlantic and super warm Arctic Ocean influence the latter part of the 'cane season?

I remeber reading from an awful lot of members that the hurricane season was going to be very active if not record breaking. Was record breaking supposed to reflect lack of activity or am I miss reading level of present activity?. My own view is that this season will end up very quiet contary to early predictions.

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I remeber reading from an awful lot of members that the hurricane season was going to be very active if not record breaking. Was record breaking supposed to reflect lack of activity or am I miss reading level of present activity?. My own view is that this season will end up very quiet contary to early predictions.

the experts take on this is the opposite, see link below

http://www.noaanews....caneupdate.html

this also

http://www.cpc.noaa.gov/products/outlooks/background_information.shtml#NOAADEF

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The Atlantic is bang on average right now and thats normal for La Nina.

A very basic lesson in La Nina hurricane seasons, esp moderate seasons. They begin late due to surpressed MJO waves (MJO waves help to create uplift in the tropics, helping storms to form) as well as a strong subtropical high pressure belt that promoted upper level lows in places that were rather unfavourable. These factors are starting to shift now and should lead to a ramp up in the next 15 days.

We won't get the high numbers expected because the forecasters didn't understand the simple fact that La Nina doesn't always equal more storms....however just because its been slow at the moment stil doesn't mean much in terms of the ACE, which is my method of choice in terms of how the season goes (Accumulated cyclone energy) as seasons like 1998/1999/1961 had pretty much nothing before the 20th August and still ended up hyperactive.

Now what is really fueling this very slow period globally is a VERY surpressed WPAC. Its amazing how slow this season has been in that basin. Just for everyones information, the WPAC makes up over 50% of the ENTIRE N.Hemispheres ACE, so if that is on a big downer then guess what...so will the N.Hemisphere...in fact its been amazingly slow in the WPAC.

Whats interesting is just how similar this year in the N.Hemisphere has been in the tropics and in fact now even in W.Europe to 1998. That year had an exceptionally slow WPAC, the EPAC was a little busier and so was the Atlantic. That year things across the world started to pick up between the 20-30th August but the WPAC still only got 16NS...which is amazingly slow.

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Yes, the extremley quiet West Pac is interesting, and if you look at satellite imagery of the basin there is a remarkable lack of convection across the basin at present. There is literally nothing out there!

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