Following up on my previous post and wanting to dig deeper...
If a spike in the cold PDO to warm creates very cold winters in the east then why aren't all el nino's in a warm PDO severe winters. Why is it that the spike in the cold PDO causes cold winters but a regular warm PDO with an el nino causes generally warm winters?
Looking at all el nino's in a warm PDO we can see warmer temperatures across north america and cooler temperatures across the arctic:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full image
500mb Heights:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full image
Surface Pressure:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full image
All el ninos in a cold PDO with a warm spike:
Heights at 500mb:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full image
Surface Pressures:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full image
I threw in 1959 which had a PDO spike as well and a very cold winter. This is just another good example of how the theory works,even in the case of an el nino following an el nino.
To sum this up, what is occurring is that because the PDO is permanently warm the pressures are lowering even more over the pacific as well as the heights. The atmosphere always wants to balance itself out so if this occurs then there will need to be more of a compensation over north america. What happened in many of these years was that there was a compensation in pressures over northwestern canada but because more of a balance was needed this also translated in a rise in heights over eastern and central america which caused warmer winters. A good example is 1982-3 which shows this pattern.You can see the warming of the arctic but the eastern U.S and canada as well because of the need to balance.
Reduced: 90% of original size [ 565 x 437 ] - Click to view full image
If a brief warming of the PDO is created then there is less of a lowering of pressures in the pacific (because of the weaker strength and shorter duration of the warm PDO) and less of a compensation of rising pressures across north america. This causes the arctic and greenland to warm without causing warming across the eastern U.S and instead it lowers the pressures across the east.
If a spike in the cold PDO to warm creates very cold winters in the east then why aren't all el nino's in a warm PDO severe winters. Why is it that the spike in the cold PDO causes cold winters but a regular warm PDO with an el nino causes generally warm winters?
Looking at all el nino's in a warm PDO we can see warmer temperatures across north america and cooler temperatures across the arctic:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full image500mb Heights:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full imageSurface Pressure:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full imageAll el ninos in a cold PDO with a warm spike:
Heights at 500mb:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full imageSurface Pressures:
Reduced: 90% of original size [ 565 x 437 ] - Click to view full imageI threw in 1959 which had a PDO spike as well and a very cold winter. This is just another good example of how the theory works,even in the case of an el nino following an el nino.
To sum this up, what is occurring is that because the PDO is permanently warm the pressures are lowering even more over the pacific as well as the heights. The atmosphere always wants to balance itself out so if this occurs then there will need to be more of a compensation over north america. What happened in many of these years was that there was a compensation in pressures over northwestern canada but because more of a balance was needed this also translated in a rise in heights over eastern and central america which caused warmer winters. A good example is 1982-3 which shows this pattern.You can see the warming of the arctic but the eastern U.S and canada as well because of the need to balance.
Reduced: 90% of original size [ 565 x 437 ] - Click to view full imageIf a brief warming of the PDO is created then there is less of a lowering of pressures in the pacific (because of the weaker strength and shorter duration of the warm PDO) and less of a compensation of rising pressures across north america. This causes the arctic and greenland to warm without causing warming across the eastern U.S and instead it lowers the pressures across the east.
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