Thunderstorms are expected to hit much of Wales on Saturday leading to warnings of localised flooding.
The Met Office has issued amber 'be prepared' alerts which come into force for the entire day.
Only extreme west and north-west Wales are expected to escape torrential downpours.
The Met Office said frequent lightning, large hail and locally strong gusts were possible in places.
"Significant flooding is possible where these do occur from surface water as well as from small, fast-responding watercourses," its forecasters warned.
The worst weather is expected to hit the east of Wales where the Met Office has an amber "be prepared" warning in place, while a yellow "be aware" alert is in force elsewhere.
Environment body Natural Resources Wales said: "People travelling tomorrow are advised to take extra care and allow extra time for their journey as driving conditions may be hazardous.
"Natural Resources Wales is advising people to keep an eye on weather reports and local news for details of any disruption in their area.
"Organisers of outdoor events are also advised to check the Met Office website for the most up-to-date forecasts."
However not everywhere within the warning area will experience thunderstorms, and spells of warm sunshine are expected at times.
If you are affected by adverse weather conditions over the weekend, please get in touch using the form below remembering to include a contact number. Alternatively tweet your pictures to @BBCWalesNewsor email newsonline.wales@bbc.co.uk
Flood warning as storms are forecast
Put the internet to work for you.
Contact us