I’ve been talking about a pattern change for a couple of weeks now and I mentioned three possible outcomes as we move towards the middle of the month, below I have quoted what I said the possible outcomes could be from a previous article.
1. High Pressure edges further North and West allowing much colder, Arctic air into Europe, the Polar Vortex weakening and allowing heights to rise will displace much colder air into lower latitudes, if this pattern does indeed setup, we will see gradually colder temperatures and an increased possibility of snowfall as we move through the second half of the month. The signal for this is tentative, but it is there.
2. High Pressure sinks Southwards over Europe allowing the Jet Stream to flatten out across the UK turning things very changeable with a mixture of sunshine, showers and strong winds. Signals for this outcome are generally rather weak, this outcome isn’t very likely.
3. High Pressure continues to hold its position over Europe, keeping Low Pressure stuck to our West and we see a continuation of above average temperatures with rain trying to push in across Western areas and then stalling against High Pressure, this outcome seems as likely as cooler outcome number 1.
Current indications suggest that out of the three outcomes, number two is now looking increasingly likely to happen with a majority of models now pointing towards High Pressure over Europe finally sinking Southwards, allowing more seasonal, Atlantic weather to take hold of the United Kingdom. However, due to the direction of the low pressure systems track, its likely that we’ll see colder, Polar Maritime air pushing across the United Kingdom bringing temperatures closer to the seasonal average, with some much needed snowfall possible across the Highlands.
Above is the NAO and AO forecast, and as you can see both are forecasted to become more positive as we move through the middle part of the month and this is indicative of Low Pressure across the Arctic and indeed, in the Atlantic suggesting things will turn increasingly unsettled.
Above is the 500MB anomaly chart which is hinting at lowering heights across Europe, as well as placing an Atlantic trough in the Mid-Atlantic which is in line with what the NAO/AO predictions.
So, as we move through the next week or so, High Pressure across Europe will finally begin to be eroded and head Southwards, whilst Atlantic Low Pressure systems begin to work there way across the United Kingdom, spells of rain are likely to push across the country though this in turn will turn temperatures to around average, with snowfalls likely from time to time across the Scottish Highlands.
Forecasters Note: Whilst my November forecast has started off well, I think it’s likely to be significantly wrong during the second half of the month with a more mobile weather pattern, rather then the cooler, blocked one that I had forecasted. Widespread heavy snow is now considered very unlikely, based on the latest weather model outputs.