Firstly I’d just like to share these couple of charts with you from todays 12z ECM run. I’m not for a second suggesting things are going to play out like this. But the model has shown what could potentially happen if everything were to fall into place.
If the above were to verify, we’d be seeing some very cold air coming down from the North-East bringing snowfall to many Eastern counties of England. Having said it, it’s just one run and one possible solution so we can’t really take this too seriously at the moment.
The NAO and AO are both forecasted to move into a negative phase and given the recent model outputs that’s not very surprising. There’s still some scatter in the output but it’s quite clear that they will be becoming negative into next week suggesting the signal for an increasingly blocked pattern very much remains.
Now we’re going to take a look at the height anomaly charts to see where they stand with things at the moment, operational models such as the ECM, GFS etc.. tend to chop and change with each run, the height anomaly charts I find are often a lot more stable and can give a clearer idea of the signal being presented.
The above chart shows extensive blocking in the Atlantic North through Greenland, through the Arctic and into the Pacific. The Polar Vortex is nowhere to be seen, this suggests colder Arctic air is likely to be displaced into the mid latitudes bringing colder weather into Europe and perhaps eventually towards the UK.
Now we’re going to take a look at the 8-10 day ECM & GFS Height Anomaly chart
Much like the NCEP chart, we see a strong signal for high pressure in the Atlantic and across the Arctic with low pressure to the South East of the United Kingdom suggesting once again that colder air will be coming in from the East.
Overall the trend continues to be for some much colder weather for the end of the month. Temperatures should begin to cool down as early as next week as blocking begins to become established and we could even see some snowfall at times across higher levels though I suspect the main theme one of increasing fog and frosts. It’s hard to say just how cold things are going to become into early December but if I was a betting man, I’d put money on increasing amounts of snowfall as colder air starts to push out of Scandinavia and over the relatively warm North Sea.