Warning: Yellow

To expect: Fog

Affected areas: London & South East England

Start time estimate: Friday midnight

End time estimate: Friday 9am

The Met Office has announced a Yellow fog warning for London & South East England for Friday.

Friday sees a Yellow weather alert in place. Meteorologists warn that dense fog will approach the region affected from around midnight. The area should expect significantly reduced visibility to last until 9am.

The Yellow warning for fog was issued at 3:01pm on Thursday, December 4.

A Met Office forecast said: “Freezing fog is expected to develop across parts of southeast England on Thursday night before clearing on Friday morning. Visibility could fall below 100 metres in places. Additionally, following rainfall during Thursday daytime, a few patches of ice could form on untreated surfaces.”

What to expect

Slower journey times with delays to bus and train services possible; There is a chance of delays or cancellations to flights.

What should you do in hazy conditions?

Give yourself the best chance of avoiding delays by checking road conditions if driving, leaving extra journey time, or amending plans if necessary. Make sure you know how to switch on your fog lights, and check they are working before setting off on your journey. Bus and train services, as well as flights may also be affected; check for updates from your travel company and follow their advice. Be prepared for weather warnings to change: when a weather warning is issued, the Met Office recommends staying up to date with the weather forecast in your area. For further details see Met Office Warnings & Advice.

What is a yellow weather warning?

The Met Office has three categories of weather warning, depending on the likely impact of severe weather and also how likely it is to strike in a particular area.

A yellow warning is issued when weather conditions are expected to disrupt travel and traffic and may impact on daily routines but are not likely to pose a risk to life or property.

An amber warning is more severe and advises people to think about changing their plans to minimise the risk.

A red warning means weather conditions are expected to be dangerous with widespread damage to property and a risk to life, with the public usually advised to avoid travelling.

The Yellow weather alert for fog will remain in place until 9am on Friday.