Ok before we start this wont affect every single part of the UK and likewise the same goes for the US, sorry Florida.
But lets take a look at the facts, The UK has thus far experienced an october which has seen repeated attempts at a blocking pattern for the mid Atlantic which if becomes sustained will allow a strong Notherly flow to take hold. Currently we have seen the attempts end up being shunted east with the UK left with a glancing blow but should this set up repeat through out winter it will almost certainly result in at least 2 or 3 significant cold spells.
Further to our East the march of snow across Siberia, Russia and in towards Scandinavia has been substantial. It is widely considered that the more snow on the ground in these areas helps to maintain a Northern latitude blocking pattern. This alone doesn’t guarantee the UK snow but it helps. We then have the fact we have low solar activity & LA NINA taking a strong hold which often sees a weakening of the jet stream.
The combination of these factors are expected to increase the likelihood of an early start to winter for the UK with model outputs already showing snowfall for Scotland, NI & Northwest England around the second week of November. Of course pinpointing the detail at this range is to far to call but its one we will keep a close eye on.
As we look over the pond to the US we see a massive increase in snow cover north of the border in Canada the likes of which bode very well for the coming winter.
As with the UK a LA NINA winter will bring with it increased snow fall as the Polar jet stream and Pacific jet streams interact, The polar bringing the cold temperatures whilst the Pacific brings the moisture.
Also like the UK the second week of November looks to herald potential for first Heavy snowfalls with the states of Utah, Wyoming, Colorado, Montana, North/South Dakota, Nabraska & Kansas all in the potential firing line.