Numerous examples of events wherein the heliospheric magnetic field (HMF) measured at a fixed point in space remains nearly radial for many hours have been reported in the literature. Such events are observed both in the normal solar wind and within disturbances driven by coronal mass ejections (CMEs). A very large fraction of these extended, nearly radial HMF intervals, whose average duration increases with increasing distance from the Sun, occur at times when the solar wind flow speed is declining gradually. Typically, when mapped back to the Sun using a constant speed-with-distance approximation, all portions of a given radial field event appear to have left the Sun at approximately the same time. Here we propose that these nearly radial HMF events result from temporally abrupt and semipermanent decreases in solar wind flow speed on these same field lines close to the Sun. The abrupt flow speed changes may be the result of an interchange reconnection of field lines that extend into the heliosphere with closed coronal loops. In our kinematic model a radially directed kink in the magnetic field connects the different spirals associated with the faster and slower flows immediately preceding and following the temporal flow speed discontinuity. With increasing heliocentric distance the length of the kink grows while the temporal flow speed discontinuity that produces it evolves into a gradual spatial flow speed decline.