Scotland is set for a big freeze next week with temperatures dropping as low as -15C.

STV weather presenter Sean Batty said cold air from Siberia, where temperatures have plunged to -30C, is heading west towards Europe.

He said this winter cold spell will be different from previous ones which were associated with low pressure systems coming in from the Atlantic.

Sean explained: "This cold event is different because it's down to something called sudden stratospheric warming (SSW), which occurred several miles above the North Pole just over a week ago.

"In just a few days, the temperature rose about 50 degrees in the stratosphere.

"The sudden rise in temperature is due to lower level winds reaching higher altitudes around the Arctic.

"This process can eventually break up and slow down the upper level westerly jet which circles the Arctic, and sometimes, as on this occasion, force the winds to turn easterly instead.

"These easterly winds then slowly descend towards the surface over the course of a week or so, and result in dramatic changes in weather type, for example in Europe, the easterlies can bring very cold air out of Russia.

"This is likely to be the coldest air to sweep the UK for a few years."

Major warming events only take place every few years but a large area of high pressure, which normally sits over the Azores, has been on the move.

Sean said: "It drifted across Scotland on Wednesday and Thursday giving us a lot of dry and sunny weather, but it's now centred over Scandinavia.

"Because winds in high pressure go around the centre in a clockwise direction, the air has started getting dragged out of Siberia.

"Temperatures in Siberia have been around -30C to -25C by day this week, and this very cold air has started to move west towards Europe."

Sean said the cold air will spread in from the North Sea on Sunday night and potentially cause some light winter flurries along the east coast for the likes of Angus, Fife and Aberdeenshire.

From Tuesday snow showers will become heavier and more frequent.

Sean added: "In situations like this, where very cold air is travelling across the relatively warmer North Sea, we can get a bit of a 'lake effect', where heavy snow showers become frequent and merge into longer spells of snow at short notice, something I will be monitoring closely throughout next week."

Temperatures are likely to start at around 4C early next week and drop to nearer freezing by midweek.

Although there will be a significant wind chill Sean said the overnight temperature will be helped by the fact it will be windy and fairly cloudy.

He added: "If somewhere in the Highlands does get a night of lighter winds with clear skies later in the week, it could drop to -15C or below.

"This really will be the icing on the cake to a winter which has had far more cold spells than recent winters, when the weather has been more about wind, rain and storms."

Some individual location records could be broken but the record low for March, which was when temperatures plummeted to -22.8C at Logie Coldstone, Aberdeenshire in 1958, is unlikely to be challenged in the next week at least.

Sean believes the cold spell could last for a few weeks.

He added: "This could be a winter bite we're talking about for some time after."