What is the polar vortex and how will it affect Peterborough’s weather during November?
Early indications are that the polar vortex could be disrupted in November, potentially leading to cold weather for the UK
At this time of year you’re guaranteed to start seeing reports of ‘snow bombs’ and ‘arctic blasts’ that are supposedly heading to the UK in the lead up to Christmas.
These sensationalist headlines are usually wide of the mark, but over recent days there appears to be a growing confidence among forecasters that the country could be in for some particularly cold weather during November.
Recent reports of an incoming cold snap have been prompted by events thousands of miles away in the Pacific Ocean, which could wreak havoc on this winter’s weather.
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El Niño is a natural climate phenomenon involving unusually warm sea-surface temperatures in parts of the tropical Pacific Ocean.
It can influence atmospheric circulation around the world, including weather patterns over Europe.
So, let’s take a closer look at how all this could impact Peterborough’s winter weather
What is the polar vortex and what does it mean for Peterborough this winter?
First, before we look at its potential impacts, let’s focus on what the polar vortex actually is.
The polar vortex is a large circulation of strong winds surrounding cold air above the North Pole during the colder months.
It develops in the stratosphere, high above the layer of the atmosphere where most everyday weather takes place.
When the vortex is strong and relatively stable, it tends to help keep the coldest Arctic air further north.
If it weakens or becomes distorted, it can influence the jet stream and atmospheric pressure patterns, potentially allowing colder air to move further south.
One process associated with these changes is known as sudden stratospheric warming. Temperatures high in the stratosphere can rise rapidly during such an event, disrupting the winds around the polar vortex.
Peterborough could also experience colder weather if atmospheric changes eventually favour northerly or easterly winds bringing colder air towards the UK.
It’s worth noting that a weakened polar vortex does not automatically produce snow.
The position of the jet stream, the direction of prevailing winds and the development of high- and low-pressure systems will all help determine what happens locally.
What role could El Niño play?
El Niño is a natural climate phenomenon involving unusually warm sea-surface temperatures in parts of the tropical Pacific Ocean.
It can influence atmospheric circulation around the world, including weather patterns over Europe.
The latest reports have discussed the possibility of a particularly strong El Niño alongside changes in the polar vortex.
These influences can interact, but their combined effect on the UK is complex.
The Met Office has noted that El Niño can favour wetter, stormier and generally milder conditions in the UK during late autumn and early winter, while a weakening polar vortex later in the season may increase the potential for colder conditions.
That means the two influences do not necessarily point towards a consistently cold winter.
Conditions could vary considerably from one period to another.