The Met Office has upgraded Thursday's warning of snow in Northumberland and the North East and extended the alerts to the weekend.
The yellow 'be aware' warning for Thursday, posted on Sunday, has been upgraded to the amber 'be prepared' level, with up to 40cm possible in the hills.
Frequent and heavy snow showers are expected from 6am on Wednesday (February 28) to 6pm on Thursday (March 1), leading to some significant accumulations. Long delays and cancellations on bus, rail and air travel could occur. Roads may become blocked by deep snow, with many stranded vehicles and passengers. Some rural communities might be cut off for several days. Long interruptions to power supplies and other services such as telephone and mobile phone networks, could occur.
The chief forecaster says: "Snow showers will bring variable snow cover, but parts of northeast England and Scotland are expected to see the most frequent snow showers from Wednesday morning to Thursday afternoon. During this time, 5-10cm of snow is expected quite widely. Where showers become organised though, most likely across Scotland and over the hills of northern England, some places are likely to have an additional 15-25cm of snow, locally as much as 40cm.
"Strong winds will lead to drifting of snow and severe wind chill, while lightning could be an additional hazard, particularly near coasts. This warning has been updated to extend the area south across parts of northern England, this particularly for Wednesday and the first part of Thursday, while the end time has been extended to later on Thursday."
Another yellow warning has been issued for Friday and Saturday, as snow showers are expected to continue over Northumberland and parts of northern Britain, bringing a further risk of ice and further accumulations of snow. Further delays to travel and public transport could occur, whilst some rural communities could become or remain cut off. Further impacts to power supplies/mobile phone coverage are also possible.