Diurnal Convective Precipitation in Lee Side of the Canadian Rockies

Convective precipitation is significant over the lee side of the foothills at high latitudes, particularly in summertime, when conditions such as an unstable atmosphere, a convergence zone along the foothills and enough moisture supply are present. At the lee side of the Canadian Rockies convective initiation have been associated with the boundary layer development from land use transition and the propagation of drylines. The propagation of the storms using Hovmöller diagrams shows a preferential eastward direction from the Rockies to the Prairies. In this work we examined the convective precipitation east of the Canadian Rockies, emphasized on the diurnal cycle. For this, a harmonic analysis to identify the diurnal and semidiurnal forcings is first applied. Along with a cluster analysis to identify the spatial transition of the phase and amplitude of the harmonics. This work is based on surface station observations and a continental scale 4km WRF modelling for 11 years from 2000 to 2011, which give us a different perspective to characterize the convective mechanisms in this region.->