Now what is interesting is that there appears to be a tropospheric based upwelling of negative mean zonal winds(-AO) which looks like joining the downwelling negative mean zonal winds form the upper layers of the stratosphere. Will this help produce another NH significant blocking event towards the end of the month? - it certainly looks on the cards.
To see where any northern blocking would occur it is worth looking at the lowest stratospheric charts (100 hPa level) to see where the vortex is strongest. The PV has followed the displacement from higher up the stratosphere and again we are seeing the bulk of the displacement over Eastern Siberia with that trailing arm towards Greenland.
We need to see what happens to that Greenland segment of vortex which I feel will be critical in determining whether we are likely to benefit from any northern blocking.
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