Has there been a Sudden Stratospheric Warming – and what does that mean for our weather?

You may have heard speculation about a Sudden Stratospheric Warming (SSW) and that a ‘Beast from the East’ is on the way with freezing conditions and widespread snow.

Is there any truth behind the headlines and what can we say about the weather for the coming month?

Well, a sudden stratospheric warming is underway, but only a minor one. The warming is expected to peak towards the end of January. The strong westerly winds high over the Arctic, called the stratospheric polar vortex, have weakened and the vortex is partially collapsing. However, the polar vortex has been unusually strong so far this year and although there has been a minor SSW, the winds are expected to rebound quickly, recovering to speeds around normal for the time of year.

Minor SSW

It can take a week or more for any impacts from an SSW to work its way down through the atmosphere and to have any influence on the weather in the UK. However,  not all SSWs lead to cold weather and widespread snow for the UK, for example, the SSW in February 2018 led to the ‘beast from the east’ whereas the SSW in January 2019 had no significant impact for the UK weather, in fact, it stayed mild for the rest of the winter.

Forecasts at present show only minor impacts are expected and that other factors, such as La Nina and the Madden Julian Oscillation are also likely to influence our weather over the next few weeks. Our predominant weather is expected to come from the west with wet and windy periods. The unsettled conditions are expected to impact the north and west of the UK at the start of February as frontal systems push south across the country, weakening as they go with parts of the south remaining largely dry. Temperatures will stay around average for many.

Changeable weather is likely to continue through to the second half of the month bringing rainfall, heavy at times, again to the north and west. The south and east are expected to see some drier and brighter periods with some lighter rain. A brief spell of more settled conditions is possible in the middle of the period, bringing a greater risk of overnight frost and freezing fog, especially under clear skies with light winds. Temperatures are expected to be generally at or slightly above average, although a brief colder spell remains possible.

The Met Office will continue to monitor the situation and, as ever, keep up to date on our forecast pages and warnings pages and by following us on Twitter and Facebook. Our app is available for iPhone from the App store and for Android from the Google Play store.

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