What a difference a week makes in Aberdeenshire. Last Monday saw temperatures climb to a balmy 17C in Aboyne.

This Monday morning? Braemar dipped to -12.1C.

Our air flow from last Thursday through the past weekend can be traced back to Northern Greenland and Arctic. As this bitter air crosses an 8-12C ocean, moisture is picked up, hence the snow and ice risk in western/central Scotland but moisture is soon lost and sucked out of the air once over Scotland.

The proof is in these recent satellite views

What a difference a year or years can make also. From the last 3-4 winters, the Aleutian low has been week while Icelandic low has been strong, hence why the UK and Western Europe has been flooded with mild oceanic air.

However, we’ve seen a strong Aleutian low with powerful Pacific jet and series of storms slamming from Alaska to the Pacific Northwest while the Icelandic low has been weak, hence the weaker Atlantic jet and frequent high pressure west of Ireland extending up into Iceland.

The below charts shows the persistent blocking high extend from the Atlantic to Scandinavia supporting frequent cold spells and persistent N/NE flow.

30-day animation of 50mb temperatures.

Vertical cross section of the polar vortex.

Frequent upper wind reversal from west to east is likely this winter when the PV is weak and fluid and Atlantic jet is weak.

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There is response in the oceans below to this upper atmospheric pattern with cooling in the N Pacific and warming in the central N Atlantic which will have significant significant feedback implications to the atmosphere once into mature winter (January-February).

Note both AO/NAO are leaning negative. Recent years have struggled to even reach neutral from positive.

Check out the below GFS 500mb height charts and notice the persistency in low pressure south of Alaska and high pressure west of Ireland extending up towards Iceland.

See today’s video.

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