Snow cover continues to expand across Eurasia ahead of schedule thanks to a weak polar vortex and persistent -AO induced northern blocking.

Moscow and Kiev both woke to their first snowfall this morning with 20cm locally.

Kiev, Ukraine last night.

Moscow before daybreak this morning.

This cold trend doesn’t appear to wane but intensify as we head for November with the Arctic Oscillation looking to sink deep into negative territory after a very brief surge towards neutral.

And so the snows continue to grow and expand westward into Europe.

The weak vortex and strong -AO enforced blocking will continue to support a solid cold pattern throughout Northern Asia.

What’s most fascinating is that we currently have an on-going polar vortex split which is likely to trigger a negative North Atlantic Oscillation which will build heights north into Greenland and Iceland and thus the westward drifting Siberian cold looks to make a UK visit.

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Check out the below GFS ensemble NH 2m temperature anomaly. Note how Western Europe starts off warm (now) but as the warmth builds into the Arctic, so the cold currently over northeast Asia eventually reaches Ireland.

GFS 850mb temperature forecast.

One important aspect to this PV split I think is worth mentioning. The positioning of the warmth at 10mb or down 50mb within the stratosphere is different to recent years. How so? Well any displacement or split has seen a piece of the vortex drift into the Europe or Greenland side of the pole which has supported a trough underneath, hence cold is redirected into other parts of the mid latitudes. This time around it appears to be favouring Western Europe.

See today’s video.

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