A line echo on the radar scope is sometimes observed across the Bay of Toyama under the winter monsoon situation. It seems to be related to the orography of the Noto Peninsula to the west and to cause a considerable amount of snowfall to the east. It is found that its appearance has a period of 2-3 hours which characterizes mesoscale disturbances and that a remarkable line echo develops when the mesoscale convergence field comes to influence.The orientation of the row is approximately in the direction of thermal wind. The “convective warming” along the coastal area results in a remarkable temperature gradient within the cloud layer which amounts to as much as 5°C/100km.The fact that this row of cumulus convection takes place in a particular locality strongly suggests the influence of orography.
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