Abstract
A description is given of two striking examples of diurnal variation in the movement of surface cold fronts in central Honshu associated with slowly moving synoptic-scale frontal systems in the warm season. In these cases, the surface cold front was intensified along the coast due to the daytime heating over the land and moved inland during the afternoon on two successive days, displaying a recurrent or oscillatory movement for more than one diurnal cycle. As a result, part of the region experienced two frontal passages repeated at an interval of about 24 hours. A number of similar examples can be found for this type of diurnal variation, indicating that it is not a rare event.
