Short‐period variations in surface pressure and wind

Periodic variations in surface pressure and wind velocity recorded by autographic instruments on 5 July 1952 are related to wave motion along a horizontal temperature discontinuity. The wave motion is considered to have been set up when the outflow of cold air from an intense outbreak of thunderstorms over the western English Channel temporarily blocked the north‐easterly airstream beneath an inversion over southern England and the Midlands. The oscillation was propagated upstream of the lower current and across the upper south‐easterly current for over 250 mi, with an amplitude approaching 200 m in the earlier stage.