Thunderstorms are set to hit today between 12:49 and 21:00. East, south, north and west Yorkshire are all expected to see thunderstorms today and tonight.
Other parts of the UK, including east midlands, west midlands, north-east and north-west England, have also all been issued the same yellow weather warning.
These thunderstorms have developed over parts of northern England and will move eastwards during the rest of today. It is expected that they will then clear into the North Sea later this evening.
These thunderstorms are now expected to intensify during this afternoon, giving around 20-30 mm of rain in an hour and perhaps 40 mm in 3 hours.
Lightning is also likely associated with the heavy rain.
What to expect
Yellow and Amber warnings represent a range of impact levels and likelihoods, which can include damage to property, travel delays and cancellations, loss of water supplies and power cuts.
According to the Met Office this yellow weather warning means:
-There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from flood water, lightning strikes, hail or strong winds
-Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services
-Spray and sudden flooding could lead to difficult driving conditions and some road closures
-There is a slight chance that power cuts could occur and other services to some homes and businesses could be lost
Saturday in Sheffield is then expected to be a dry, fine and warm day, accompanied by light winds.
Prolonged sunshine is expected during Saturday morning, with some fair weather cloud developing through the day. Maximum temperature 25 °C.