Video forecast for heavy snow forecast for Friday

17 01 2013

A band of snow will push into the west into Friday morning with parts of Wales, the west of England and later Northern Ireland particularly at risk of heavy falls of snow and blizzard conditions in strong winds.

Met Office severe weather warnings have been issued for the heavy snow. A red warning has been issued for upland parts of southern Wales where accumulations of 10 to 15 cm are expected. Up to 30 cm is possible over the hills and blizzard conditions are likely.

An amber warning is in place for other parts of Wales, western England, the Midlands and central and southern England, as well as Northern Ireland where accumulations of 10 to 15 cm are expected and 20 cm or more over the hills.





Heavy snow forecast for the UK

17 01 2013

A band of snow will push into the west into Friday morning with parts of Wales, the west of England and later Northern Ireland particularly at risk of heavy falls of snow and blizzard conditions in strong winds.

Met Office severe weather warnings have been issued for the heavy snow. A red warning has been issued for upland parts of southern Wales where accumulations of 10 to 15 cm are expected. Up to 30 cm is possible over the hills and blizzard conditions are likely.

An amber warning is in place for other parts of Wales, western England, the Midlands and central and southern England, as well as Northern Ireland where accumulations of 10 to 15 cm are expected and 20 cm or more over the hills.

Met Office weather warnings help us all plan, prepare and protect ourselves and others from the impacts of severe weather. A red warning from the Met Office means that we need to take action to keep ourselves and others safe from the impacts of the weather. Widespread disruption to travel and other services is likely. All of us should consider changing our plans and avoiding dangerous areas.

Whilst snow will fall over most areas, the far west, including Cornwall and extreme western parts of Wales are expected to see the snow turning to rain, with the rain replacing snow across other parts of southwest England during the day.

UK snow fall depths

Andy Page, Met Office Chief Forecaster, said: “The snow is expected to be heaviest during Friday morning across Wales and the southern half of England.

“Clearly there is the potential for significant disruption to peoples plans. We should follow the advice of the emergency services and local authorities to help keep ourselves, our families and our communities safe in light of the forecast.”

Darron Burness, head of the AA’s severe weather team, said: “With the outlook remaining cold, drivers need to be prepared for possible disruption.

“Before heading out, check the Met Office weather alerts and traffic reports and allow a bit more time for your journey, as you don’t want to rush on potentially icy roads. Do the basic checks on your car and, in case of any problems, carry plenty of warm clothing, blankets, de-icer and scraper, some food, hot flask and a fully-charged mobile.”

Steve Crosthwaite, head of the Highways Agency’s National Traffic Operations Centre said: “We advise drivers to check road conditions and the Met Office weather forecast before they set off and during severe weather to consider whether their journey is essential. They may want to delay their travel until conditions improve and to allow our winter fleet the chance to treat the roads.

“Our traffic officers are working round the clock to monitor the network, deal with any incidents and keep traffic moving.”

Over the weekend we will see less severe conditions but further outbreaks of rain, sleet and snow are possible in places. The snow that has fallen will be slow to melt and ice will continue to be a risk, especially at night.

By thinking ahead we can all be better prepared for severe weather. Throughout the winter, the Met Office works with agencies across the UK to help keep the country safe, well and on the move.





What’s bringing the stormy weather to the UK?

24 09 2012

The UK has seen some very wet and windy weather since the early hours of Sunday morning and that is set to continue in places for the next couple of days – but what has brought these disruptive conditions?

As is the norm, a low pressure which moved in from the Atlantic is to blame, bringing bands of heavy rain and strong winds (as you can see from the tightly packed isobars on the image below).

Forecast synoptic chart for 12:00 on Tuesday 25 September showing the low pressure over the UK.

Despite some reports to the contrary, this low is not what’s left of tropical storm Nadine, but is a completely separate entity – the remnants of Nadine are currently sitting close to the Azores far to the south of the UK.

Some warm tropical air dragged over by Nadine was sucked up into the low pressure, however, giving it some extra energy – essentially increasing its potential for strong winds and rain.

This isn’t unusual though, virtually every weather system we see will have had some input of sub-tropical air during its evolution.

There are two more notable features of this low pressure, however. Firstly, it has remained unusually active as it sits over the UK, leading to the strong winds and heavy rain.

This is due to the fact that, as the low pressure system moved north across the UK, it has also pulled in cooler polar air from the north.  This cold air has come up against the warm sub-tropical air, re-invigorating the depression and allowing it to continue to deepen over the UK.

Secondly this low pressure is lingering for longer than we would often see. The reason for this is down to the position of the jet stream, a narrow band of fast moving winds high up in the atmosphere which ‘steers’ weather systems.

Normally the jet stream runs fairly directly from east to west and pushes weather systems through quite quickly. Similar to earlier this year, the steering flow of the jet stream is currently in a meandering mood – looking much like a river, curving north and south as it heads west across the Atlantic (we call this a meridional flow, with the more linear west to east flow being called a zonal flow).

When it meanders, weather systems can get stuck in the ‘peaks and troughs’ it creates – so they get stalled in one spot rather than moving on. The below picture of the jet stream as at 12:00 today shows with the steering flow of the jet over France and the UK in the resulting trough.

The weather system will move on during the day on Wednesday, but that still means the UK will have had three days of unsettled weather.

Like our weather, the jet stream can change rapidly and it’s difficult to forecast precisely what it will do for more than a few days ahead – so there’s no reason to expect it to continue to behave in this way and there’s plenty still to play for in terms of our autumn weather.

The low pressure system that is affecting the UK is unusually deep for September, with the lowest air pressure recorded so far being 973mbs. To find a similarly intense low pressure system in September you need to go back to 1981, when pressures below 970mb were reported over a period of 24 hours. Like this week’s, this low pressure system brought unsettled weather as it crossed the British Isles – starting in the Isle of Man and tracking east and then north to cover Cumbria, Northumberland, eastern Scotland, Orkney and Shetland. There have been other times when pressures as low as 970mb were recorded in some parts of the British Isles in September, such as in the Isles of Scilly in 1995 and others across the far north or west of Scotland or Northern Ireland, however none were as widespread as the low that pushed across the UK in 1981.








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