The Met Office has now issued a yellow warning of rain for South Yorkshire, with thunderstorms also expected to hit the region.
The warning has been placed on the region from midday today to 4pm tomorrow.
Issuing the warning this morning, a Met Office spokesman said: "Some areas of heavy rain will move north-eastwards during Sunday and into Monday with some locally torrential downpours and thunder possible.
"Many areas will see rain at times but the extent of the most intense and thundery downpours will be limited.
"Only small areas are likely to see these downpours at any one time.
"This could result in some disruption, with sudden flooding of roads, transport routes, homes and businesses possible locally.
"Frequent lightning in association with the heaviest rain may also temporarily disrupt power supplies.
"However, given the hit and miss nature of the heavy rain and thunderstorms, many places will likely see little or no impacts. This is a further update to extend the warning area a little further North."