Scudding clouds

When they say "The clouds were scudding along ... " this is what they mean. These low-lying cumulus clouds are  "scudding" along driven by the brisk winds.

scud  (skd)*

intr.v. scud·dedscud·dingscuds
1. To run or skim along swiftly and easily: dark clouds scudding by.
2. Nautical To run before a gale with little or no sail set.
1. The act of scudding.
    a. Wind-driven clouds, mist, or rain.
    b. Ragged low clouds, moving rapidly beneath another cloud layer.