The Polar Vortex is currently undergoing a major Sudden Stratospheric Warming (SSW) with the zonal winds reversing.

When the stratosphere warms, the temperatures over the Arctic rise, and have currently risen to around 1C. That may not sound warm, but to put that into perspective, that is over 50C above its normal temperature!

The winds in the stratosphere are now reversing after signs of weakening, from westerly to easterly, leading to a displacement of the Polar Vortex.

When this event occurs, it can either cause a displacement (expected) or split. Though even after a displacement a split is still possible later in the month.

The consequence of this can be cold air spilling southwards and producing a cold blast across northern Europe. However this is not guaranteed and we are not anticipating seeing results of this until around early springtime, in March. The rest of February currently looks to continue its mild set-up.

There is often a lag of a couple of weeks after a stratospheric warming event for the cold air to propagate and affect our weather pattern in the troposphere.

While an SSW event happens on average every 2-3 years, not every event is the same and depends a lot on the pre-existing weather in play.