Coast discussion: The recent runs of the GEM (00 and 06) show a similar track and precip envelope to yesterday’s model runs. The GFS is similar and the UKMet slightly faster.
The bulk of the moisture moves across VI from West to East beginning later today/tonight. Scattered flurries are possible today ahead of the steadier precipitation. The steady precip reaches Vancouver by midnight or just after. There’s a lot of warm air indicated with freezing levels likely to rise quickly on Monday morning to somewhere near of 1000 to 1200 metres.
The window for snowfall for the South Coast remains brief: roughly 6 to 9 hours for YVR. The dry air near at low levels will take time to saturate, and by the time it does and snow begins accumulating, the warm air will be ready to flood in. There’s just not enough time to allow for a major snowfall event in Van. Amounts of 2 to 5 cm are expected. The exception is the eastern FV near Hope and in Howe Sound and WAE. Up to 10 cm is possible in WSK and WAE.
Freezing rain is also possible over Metro Van, but the window for freezing rain is also brief. There is a better chance over the FV and WSK as well as inland sections of VI.
A fairly disorganized circulation can be seen on sat pix near the developing low well off VrIsl. This is the system that will produce modest warm overrunning on the South Coast late tonight into Monday. Challenging phase issues are associated with the low QPFs. Because of the very dry, cold air in the boundary layer and active outflow winds, we could see hours of virga tonight before the precipitation starts reaching the ground.