A couple of days ago I mentioned that the models were starting to hint at a period of colder weather from around the 18th onwards, this evening, all three of the major models have updated to show a Northerly Outbreak from around the 17/18th October. I’ve annoted the charts below to show this.
All three models agree on the same thing. High Pressure will develop in the Atlantic and extend Northwards into Greenland, allowing Low Pressure to travel Southwards into Scandi or down the Eastern side of England dragging in cooler, Northerly air. The High in the Atlantic does however serve a greater purpose, it allows warmer air up into the Arctic causing Sudden Stratospheric Warming, research suggests that this helps High Pressure to build across Greenland and the Arctic forcing the AO into a negative state.
The important thing to remember however, if this Northerly does come to pass, it will not be a widespread, bitterly cold event. It will bring temperatures down to below average and we’ll probably see quite a widespread frost, however any snowfall will be limited to the Scottish Mountains because cold air simply hasn’t fully established itself in the Northern Hemisphere yet.
If you like cold and snow however, it’s promising to see such setups appearing on the models this early in the season. I’ll update you on the situation over the coming days.