Two yellow weather warnings has been issued for south Wales this weekend as thunderstorms and heavy rain looks set to cause disruptions across the area.

The Met Office has issued two yellow weather warnings for the weekend:

The first will be in place on Saturday (September 21) from 1am until 11.59pm with thunderstorms and heavy showers forecast to cause flooding, power cuts and danger to life in some instances. 

The second weather warning, issued by The Met Office, will be in place on Sunday (September 22) from 12am until 11.59pm.

This warning comes as heavy rain looks set to cause disruptions across the county.

Both these yellow weather warnings will be in place across all of south Wales covering the following locations:

  • Blaenau Gwent
  • Bridgend
  • Caerphilly
  • Cardiff
  • Carmarthenshire
  • Ceredigion
  • Merthyr Tydfil
  • Monmouthshire
  • Neath Port Talbot
  • Newport
  • Rhondda Cynon Taf
  • Swansea
  • Torfaen
  • Vale of Glamorgan

These weekend weather warnings come off the back of a similar alert issued for south Wales for Friday (September 20).

What to expect from the yellow weather warnings in South Wales

Saturday (September 21)

The Met Office said the yellow weather warning was issued across south Wales due to thunderstorms and heavy showers which could cause some disruptions.

The thunderstorms associated with the yellow weather warning are also set to cause:

  • Difficult driving conditions and road closures as a result of spray and sudden flooding 
  • Some communities could become cut off by flooded roads
  • Delays and cancellations to train and bus services
  • Power cuts and disruptions to other services
  • Homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds
  • Fast flowing or deep floodwater causing danger to life

The yellow weather warning on Saturday (September 21) will impact all of Wales.The yellow weather warning on Saturday (September 21) will impact all of Wales. (Image: Met Office) A Met Office spokesperson added: "Whilst there is some uncertainty in the details , scattered showers and thunderstorms are likely to develop and spread northwestwards at times later on Friday night and through Saturday.

"While much of the time it will be dry, and not all places will see these, where they do occur 20-40 mm could fall in less than an hour, with a small chance of isolated accumulations of 50-70 mm over the course of a few hours.

"In addition, hail and frequent lightning may accompany the most intense storms, especially during Saturday afternoon and evening in parts of the Midlands, southern England and east Wales."

Sunday (September 22)

The Met Office said Sunday's yellow weather warning was issued across south Wales due to heavy rain which will bring potential disruptions.

The heavy rain associated with the yellow weather warning is also set to cause:

  • Difficult driving conditions and temporary road closures as a result of spray and flooding
  • Rural communities could become temporarily cut off by flooded roads
  • Significant delays or cancellations to train and bus services
  • Homes and businesses could be flooded, causing damage to some buildings
  • Power cuts and loss of other services

A Met Office spokesperson added: "Showers and thunderstorms are expected to merge into broader areas of heavy rain across parts of Wales, central and southern England during Sunday.

"Whilst the strongest signal for impactful rainfall totals appears to be centred across east Wales and west-central England, there is potential right across this highlighted region for some areas to see 30-50 mm in less than 6 hours, with a few places receiving 60-80mm over the course of 12-24 hours.

"Southwest England looks likely to see some heavy rain during the early hours of Sunday morning, breaking up into slow-moving, heavy and in places thundery downpours during the day time.

"Meanwhile, the areas of heavy rain are likely to continue pushing north and west, becoming slow moving across some northern and possibly eastern reaches of the warning area during the rest of Sunday."

How to prepare for the yellow weather warnings in South Wales

The Met Office has issued advice on how to prepare for the yellow weather warnings and the risks they pose.

A Met Office spokesperson said: "Consider if your location is at risk of flash flooding. If so, consider preparing a flood plan and an emergency flood kit. Prepare to protect your property and people from injury.

"Before gusty winds arrive, check to ensure moveable objects or temporary structures are well secured. Items include; bins, garden furniture, trampolines, tents, gazebos, sheds, and fences.

"Give yourself the best chance of avoiding delays by checking road conditions if driving, or bus and train timetables, amending your travel plans if necessary.

"People cope better with power cuts when they have prepared for them in advance. It’s easy to do; consider gathering torches and batteries, a mobile phone power pack and other essential items.

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"If you find yourself outside and hear thunder, protect yourself by finding a safe enclosed shelter (such as a car). Do not shelter under or near trees, or other structures which may be struck by lightning.

"If you are on an elevated area move to lower ground. Be prepared for weather warnings to change quickly: when a weather warning is issued, the Met Office recommends staying up to date with the weather forecast in your area.

The yellow weather warnings will be in place across all of south Wales from 1am on Saturday (September 21) until 11.59pm on Sunday (September 22).