A yellow weather warning for thunderstorms is now in place across Wales until 10PM today (Sunday July 20).
The warning comes after the Met Office issued a yellow weather warning for rain yesterday.
Scattered heavy showers and thunderstorms are expected to develop during the course of the day, causing some localised flooding and transport disruption.
Rainfall amounts will vary from place to place but in some locations 20-40 mm is possible within a couple of hours.
Heavy downpours of rain will be the primary hazard, but lightning strikes are also likely along with the potential for hail and gusty winds.
Where flooding and lightning strikes occur, there is a chance of delays or cancellations to train and bus services in the area. Spray and flooding around these areas could also lead to difficult driving conditions and some road closures.
To give yourself the best chance of avoiding delays during this time, check road conditions if driving, check bus or train timetables and amend travel plans if necessary.
The Met Office has warned that there is a slight chance of power cuts and loss of other services to some homes and businesses.
There is also a small chance that homes and businesses could be flooded, with potential damage to some buildings from floodwater, lightning strikes, hail or strong winds.
If you believe that your property is at risk of flooding, the Met Office has advised that you prepare a flood plan and an emergency flood kit.
When preparing for power cuts, consider gathering torches and batteries, a mobile phone power pack and other essential items.
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.