The forecaster has issued a yellow weather warning for the county and warned of up to 80mm of rainfall in some areas. The warning remains in place until midnight, when the rain is expected to ease. A spokesman for the Met Office said: A slowly southward-moving weather system will give 15-30 mm of rain quite widely across the area, with possibly as much as 60-80 mm in places through the whole day. Locally, 20-30 mm could fall within an hour. Some thundery bursts are likely, possibly locally torrential. Some transport routes may be affected by localised flooding leading to longer journey times. In addition, flooding of homes and businesses is possible. Dan Holley, meteorologist for Norwich-based Weatherquest, said the heavy rain started before dawn on the north Norfolk coast and was moving slowly down towards the south. He said: It is going to rain for most of the day.