The Government Flood Information Service issued the warning at 6.30pm today.
River levels are forecast to rise at the Ashford river gauge as a result of persistent heavy rainfall.
Consequently, flooding of roads and farmland is expected to begin between 8pm and 10pm today, Tuesday August 25.
Areas most at risk are low-lying agricultural land and roads including Ashford and Bakewell areas.
Further heavy rainfall is forecast over the next 12 hours.
The warning adds: “We expect river levels to begin rising at 19:00 on 25/08/20.
“We are closely monitoring the situation. Please avoid using low-lying footpaths near local watercourses and plan driving routes to avoid low-lying roads near rivers, which may be flooded.
"This message will be updated in 8 hours, or as the situation changes.”