The warning is in place until 10pm today (Friday) with another warning returning on Saturday between 9am and 6pm.
Flooding, lightning strikes and hail are all included in the experts' warning with warnings about power cuts and as well as disruption to public transport.
The Met Office website warns: "There is a chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.
"There is a chance of fast flowing or deep floodwater causing danger to life.
"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 chance that power cuts could occur due to either flooding or lightning strikes.Other services to some homes and businesses could be lost."