Stewart:
Monitoring tells us that the cooling is most pronounced around 60N, which is further south than under most strong vortex events. What is really striking at the moment is the modelling of the tropospheric vortex; the primary centre west of Greenland; the second forming in the Bering Straights - totally out of kilter with Ninas and likely to cause no end of problems with NWP as they will be preconditioned to programme a ridge where troughing is developing. Slowly, slowly, starting to develop as a hemispheric pattern but going to take a long while to blossom.
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Are you saying that signals are emerging to support what you expect to unfold in 6 or 7 weeks time?
Stewart:
Tentatively yes, particularly in the Pacific which is now starting to develop an upper low which will keep the main core of the Pacific ridge in the NE off Alaska setting the downstream wave length. I've flagged the possible role of the Madden Julian Oscillation wave in the Indian Ocean in October as a possible route map for pattern change in January, and one of the key December developments was an upper low starting to form in this area. Hopefully in the next 7-10 days I can post the pressure anomaly for this month and the comparison with those MJO analogue years which should begin to give extra confidence for change in January.
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