An underlying yellow weather warning for thunderstorms remains in place which covers almost the whole of the region.
The amber warning came into effect at noon and is valid until 10pm tonight.
The yellow warning runs from noon to midnight tonight.
Heavy, thundery showers will develop this afternoon and last through the evening. They could bring some intense, localised downpours and possible flash flooding.
Lightning hail and gusty winds are also likely.
While many places will miss the heaviest showers, where they do occur, up to 40mm of rain could fall in an hour, with locally up to 80mm in a few hours.
Showers will start to merge to longer spells of rain in the evening, but ease in intensity.
Residents are urged to take care during this time and be prepared for sudden changes in conditions, particularly whilst driving.