Interesting Scenario....

[Wnghs2007]

There is an interesting Scenario that could come to fruition in the next 2 weeks that could possibly lead to a more sustained Negative Nao to end out the winter.

The main Culprit: The new Ocean low shown by all models.


The Atlantic Pattern (Couplet) needed for a Negative Nao is a Warm-Cool-Warm Tripole Couplet. As of right now we cannot have a sustained Negative Nao because there is just one continuous pool of warm water in the Atlantic basin.

Now we introduce the Ocean low. Which will most likely be be quasi-stationary drifting to the North East on most of the models at least. With the Central Atlantic Ridge to its East the system, as it moves very slowly north, will be forced to either continue drifting North or stall out.

With the Ocean low having to slow down and/or stall out. It will continue to churn over the warm pool in the Atlantic Ocean. As it churns, since it is moving so slowly, will bring copious amounts of Upwelling and cause the warm pool to split into two warm pools and a Cool Pool in between and hence you get the Atlantic SSTA Couplet Tripole which is favorable for a Negative Nao.

If this does happen to be the situation, which atleast according to the models it will. You will see the next two weeks be warm, and then another pattern oscilation right around mid month and finally a sustained period of Negative Nao and below normal temps in the east.

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K.C.