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Originally Posted by Hill Country
I think the new climate zone sounds more accurate. But I haven't looked at the specifics of each climate type one to know which one is technically correct.
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No we are indeed a humid sub-tropical zone. To be transitional semi-arid our yearly precipitation would need to be between 26 to 28 inches. Despite the long term hydrological drought (no longer in an agricultural drought), our yearly precipitation has actually risen from 32 to 34 inches. 30 inches is the lowest yearly rainfall to be considered humid sub-tropical.
Since the last Super El Niño back in 97/98 our longer term climate has been in what is known as a -PDO (negative Pacific Decadal Oscillation) where the east Pacific has generally below average surface water temps while the west Pacific has generally above average surface water temps. This is a longer term cycle that affects climate in 15 to 30 year intervals. So for the past 15 years we have been in a -PDO which favors below average yearly precipitation, above average temperatures shorter, weaker El Niños and more frequent La Niñas, the last of which was a multi-year La Niña that gave us the Summer of Hell in 2011 and dropped our lake levels. So for all of us who are from here and are 30 years old and above, we know from 2000 on our overall climate has not been the same as it was in the 80s and 90s.
Since last year there has been a shift from a -PDO to a +PDO now waters along the east Pacific all up and down the west coast of north, central and south America are above average with below average water in the west Pacific. Of course that means the opposite of what we have seen since the end of the 90s. A +PDO favors above average rainfall, below average temperatures less and weaker La Niñas and more frequent and stronger El Niños. Good news for us not just for the short term. It's still fairly early and it will be another year or so before it's confirmed but all signs point to a major shift back to a generally wetter long term cycle that would last between 15 years on the short side to 30 years on the long side.
Having said that, we are still learning about what effects climate change due to global warming has on the PDO cycle and indeed we are only just beginning to understand the PDO cycle and it's impact on global weather patterns. My specific interest is studying this cycle along with the ENSO and MJO because it is the Pacific that dictates our local climate and weather here in Austin and Central Texas moreso than the Gulf. The Gulf gives us low level moisture and a 3 to 4 month more prominent role during the summer months but the rest of the year the Pacific controls our weather with storm systems as well as mid to upper level moisture. I keep track of the latest research and updates. If you can get a good grasp of understanding the Pacific cycles then you have a pretty good idea of how the weather will be here 3 to 6 months out from now.
One last point to make. Even if we are entering into a +PDO cycle, that doesn't mean we won't get droughts but instead of droughts lasting years, they should only last just months. There will be extremes on both ends of the spectrum and with climate change these extremes will continue to get more erratic. In the mean time enjoy the rain and the greenery.
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Yeah, I read that in the Austin Business Journal.
Honestly I can deal with the ABC and CitiBank buildings, but the Sovereign and especially the BB&T are just not good uses of the land.
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