Met Office responds to reports snow to hit UK - how snow is forecast
A Met Office video explains what’s considered when forecasting snow in the UK.
The Met Office has responded to reports that parts of the UK could be hit by snow later this month.
The national weather service’s long-range forecast references a shift in pattern, however the forecaster says it’s too early to say whether the country will see snow before the end of October.
UK Met Office long-range forecast
Wednesday October 15 to Friday October 24
High pressure is expected to be the dominant weather type across the UK at the start of this period. Whilst some rain and drizzle is likely in parts of the southeast and north, mainly over the higher ground, much of the UK will be predominantly dry. Cloud amounts will vary, starting predominantly cloudy, but most areas will see some spells of sunshine and there could be a few isolated fog patches overnight. Temperatures are likely to be close to normal for the time of year. During the second half of this period, there are signs that the overall pattern will shift with low pressure systems probably moving in from the west in some fashion. However, details of any wetter and more unsettled weather are still very uncertain.
Saturday October 25 to Saturday November 8
This period is likely to see changeable conditions across the UK with low pressure systems tending to dominate. Showers or longer spells of rain are likely at times, perhaps heavy in places. There will however likely be some temporary drier interludes at times. Temperatures will probably be close to normal.
How the Met Office forecasts snow
In a video explainer, the forecaster said: “When it comes to predicting snow, a change in temperature of just one degree can mean the difference. But this small temperature change is also determined by other factors.
“The air tends to be colder on hilltops. A village at 300 metres may be cut off by snow, whilst a neighbouring village at sea level just gets rained on. Proximity to the sea also matters for an island nation like the UK. Seas and oceans have a moderating influence on climate, keeping us milder in the winter and cooler in the summer than would be the case if we were in the middle of a continent. Sometimes, just a few miles inland from the coast can be the difference between rain and snow.
“The intensity of the precipitation – rain, sleet or snow – is crucial. Water needs energy to evaporate, which it takes from the surrounding environment. Rain evaporates as it falls and takes heat out of the atmosphere. The longer and harder it rains, the more cooling takes place. If the temperature is already close to zero, enough cooling can result in snow.
“If [snow] arrives early in the morning following a frosty night, it can settle and disrupt the rush hour. A couple of hours later, the roads may have warmed up with the snow melting on impact. And of course, when snow arrives in the form of showers, just like rain showers, these can be very hit and miss.”
The three factors the Met Office considers when forecasting snow in the UK
According to the Met Office, meteorologists consider the following when forecasting snow:
Where the air has come from
If air has come from a warmer area, or has spent a long time over mild water, then it would be harder to generate snow. If the air is coming from a cold region, then there’s a chance of snow being a possibility.
Very heavy precipitation
Most precipitation in the clouds starts off as snow or supercooled raindrops, and often melts before it comes to ground. In winter, intense precipitation can keep temperatures lower closer to the ground, increasing the chance of heavy rainfall turning into snow.
When warm air meets cold air
Presenters often talk about weather fronts between warm and cold air. In the winter, these fronts can introduce the moisture and conditions for snow to fall.
Met Office Yorkshire and Humber forecast
Saturday October 11
A bright day after any early mist and fog patches clear. Sunshine may be hazy at times, though long sunny spells likely for most. Light winds. Maximum temperature 17 °C.
Sunday October 12 to Tuesday October 14
Early mist and fog patches clearing Sunday, then bright and sunny. Cloudier Monday and Tuesday with some drizzle possible. Mild by day and by night. Winds remaining light.