Vincent Fitzsimons, SEPA's Head of Hydrology and Flooding Services, said:
"Flood Alerts are now in place for much of the country. We are expecting localised thundery downpours from late Friday morning and throughout the weekend. These downpours, which will be intense but very localised, could occur almost anywhere in Scotland.
"Where downpours occur this could lead to flooding from small watercourses and the effects of this could be significant in urban areas if drains become overwhelmed. The downpours will begin suddenly with little possibility of warning.
"We would advise the public to be prepared in advance particularly if they are out and about or attending outdoor events over the coming days. We would also advise the public to be mindful of the conditions if they are driving and to follow the advice of emergency services. Do not drive into floodwater.
"We will provide further updates as appropriate. We would encourage the public to remain vigilant, especially in areas susceptible to flooding and sign up to Floodline on 0345 988 1188 for the most up to date alerts.
"As the national flood forecasting and flood warning authority, we work in close partnership with the Met Office through the Scottish Flood Forecasting Service, to provide daily updates to Local Authorities and first responders on the potential for flooding across Scotland."