The Met Office alert - which includes Derbyshire and Nottinghamshire - was issued at 11am today and is valid until 2am tomorrow.
A Met Office spokesman said: "Further spells of rain, heavy and thundery at times, will affect parts of southern Scotland and northern England through the rest of Wednesday and into early Thursday.
"There is a risk of more severe thunderstorms breaking out over parts of the Midlands, northern England and north Wales from late Wednesday afternoon onwards into Wednesday night, leading to torrential downpours, frequent lightning, very large hail and strong gusts of wind.
"This could result in some disruption, more likely from late Wednesday afternoon, which may include sudden localised flooding of transport routes, homes and businesses.
"Frequent lightning in association with the heaviest rain may also temporarily disrupt power supplies - while damage from large hail could occur on a very localised scale.
"However, many places will likely miss the worst of the storms and see little or no impact."