Natural Resources Wales (NRW) is urging people to be cautious after the Met Office issued a yellow warning for thunderstorms for 10 August which could quickly cause flooding in the hardest hit areas.
Although the alert covers the entire country, there is a high level of uncertainty regarding which parts of Wales will see the most severe storms.
Scott Squires, NRW Duty Tactical Manager said: “We are expecting thunderstorms to develop across Wales later this afternoon and into this evening and a yellow weather warning has been issued by the Met Office.
“These storms will be very localised but rainfall could be heavy where they do occur. Predictions suggests that the storms will impact most heavily on mid and north Wales and will bring with them gusty winds, lightning and bouts of heavy rainfall.
“We’re asking people to take care in these conditions – especially if they encounter flooding on pavements and roads.
“There could be localised flooding, which will happen very quickly, as drainage systems could become overwhelmed where the heaviest showers occur.
“Some smaller rivers could overtop their banks, particularly in steep, hilly areas and in urban areas. Driving may be hazardous and public transport systems may be disrupted, so remember to check for the latest weather and travel information before you travel.
“We are keeping in close contact with local authorities and our emergency partners to ensure people and communities are as prepared as possible for these unpredictable storms. This weather pattern is expected to last from Monday to Thursday.”
NRW is recommending that the people of Wales stay updated on the weather through the Met Office and other weather reports, and to use the NRW website to see the latest on flood warnings.