16 hours Ago
Snow is expected to hit parts of Britain this month but there is a good chance you won't see any of it. Forecasters said any snow will likely be confined to high ground in the north - such as mountainous areas - as it usually happens at this time of year. But what about our towns and cities? Well, in the second half of November, temperatures could take a sudden plunge.
The new week begins on a grey, drab and dull note for most with widespread cloud and pockets of drizzle ☁️ Brighter spells most possible across northern Scotland, where Monday starts on a chilly note : "Essentially, we need the air to be cold enough, and a supply of moisture. Let’s tackle the cold bit first. "To get cold air across the UK we need winds from the north or east.
Northerly winds (i.e. air travelling from north to the south) bring the air straight from the arctic and over a cold sea to reach the UK.
In winter, easterly winds (i.e. travelling for the east to the west) are cold because they arrive from the cold continental interior of mainland Europe.
"However, there is another way which requires very little wind at all - high pressure that becomes established across the UK for a long time in winter. Provided that skies are clear, temperatures can fall gradually day-on-day because the sun is weak and there is little cloud to keep in any heat at night. "The most common wind direction in the UK is south-westerly though, so more often than not we get relatively mild air from the Atlantic bringing rain, rather than this cold air from the north and east which often turns any rain to snow.
"What about the moisture? Often with the cold easterly winds, and the air travelling over so much dry land, there is very little moisture in it to form the snow and we end up with some crisp winter sunshine instead. "We either require the cold air to meet a rain-bearing weather front and turn it into snow, or for the cold air to pick up enough moisture from its short journey across the North Sea, to form showers. "There are also the effects of air rising up hills and mountains.
As it’s usually colder higher up in the atmosphere, when the air rises up the hill, it becomes colder, and condenses to form cloud and precipitation. "The precipitation will either be rain or snow, depending on just how cold the air is, and where the “freezing level” is.".
