Offshore propagation of coastal precipitation

Analyses are performed for various heating depths, mountain widths, stability, Coriolis effect, background mean wind, and friction. Calculations reveal how these factors affect the amplitude, dissipation, initiation phase, and propagation speed of the diurnal disturbance. The propagation of precipitation triggered by land–sea breezes is distinguishable from that triggered by a mountain–plains circulation.

Convection resulting purely from mountain heating begins earlier, propagates slower, and damps faster than that of the land–sea breeze. For mountains near a coast, slower propagation and stronger earlier convection result from a resonance-like combination of two dynamical mechanisms. The propagation of precipitation is initially triggered by the mountain breeze near the coastal mountain.

Over the open ocean, the dominant signal propagates as that of the land breeze but with stronger convection.