Met Office Flags Record-Early Stretch of the Arctic Polar Vortex
The Met Office says the stratospheric polar vortex is unusually stretched, and a sudden warming could be the earliest on record. Effects on UK weather are unclear.
The Met Office says the stratospheric polar vortex above the Arctic is already unusually stretched, and forecasts suggest it will drift further from the North Pole. If a major sudden stratospheric warming follows, the Met Office warned, it could be the earliest on record, according to a report by LondonLovesBusiness.
A disturbed vortex can make cold air more likely to reach Britain later in the month and into winter, but meteorologists stress it does not automatically bring snow, freezing temperatures or a long cold spell.
What is happening high above the Arctic
The polar vortex is a large circulation of strong winds in the stratosphere that normally helps keep freezing air bottled up around the North Pole. The Met Office attributes the current disturbance to “wave two” activity, in which two large atmospheric waves push into the vortex from opposite directions. The agency says this activity is considerably stronger than average for the time of year.
The information comes from Met Office forecasts, which are model projections rather than observations of what will happen. The source report does not give wind speeds, temperatures or dates for the expected warming.
How a weak vortex can reach the ground
A weakened vortex can disrupt the jet stream, the high-altitude current of air that helps steer weather systems across the Atlantic. If the resulting pattern lets high pressure build in the right places, colder northerly or easterly winds could carry Arctic air toward the UK.
That chain has several steps, and each is uncertain. Such disturbances can take several weeks to influence weather at ground level, so any effect would not be immediate. The Met Office says the situation warrants close monitoring and that the eventual impact on British weather remains uncertain.
Blackout scripts published separately
The report links the vortex news to a separate government document. The Department of Health and Social Care has published emergency public health scripts, prepared by the UK’s four chief medical officers, for a total power outage affecting Great Britain. They were developed with input from the UK Health Security Agency and public health agencies in the four nations. The government says they are not a sign that a blackout is expected.
The scripts assume mobile networks, internet and television would be disrupted. Advice would instead go out on BBC Radio 2 and Radio 4, so people would need battery-powered, wind-up or car radios. The material covers keeping warm, food supplies, safe water and sanitation, and carbon monoxide risks from improvised heating. It says generators must stay outdoors, at least six metres from buildings.
Why it matters
A sudden stratospheric warming is one of the signals forecasters watch because it can shift winter weather patterns over Europe. An event this early in the season would be unusual, which is why the Met Office drew attention to it. Whether it leads to a cold winter in Britain is not known, and the agency has not said a cold spell is certain.
Readers should follow official warnings and local authorities, including Met Office forecasts, for any severe weather.
Source: LondonLovesBusiness
