A strong zonal (west to east) flow will drive a low pressure system towards the Alaska Panhandle today. A fairly strong warm front will move onto the Central and North Coasts bringing heavy precipitation, strong winds and rising freezing levels.
On Monday and Tuesday a ridge of high pressure builds from the south and a series of systems will be aimed largely at the North Coast. A moist, sub-tropical moisture stream will feed these systems so expect moderate to heavy precip through the week.
A dry, warm airmass will remain over southern BC.
Late Tuesday and early Wednesday, a weak upper trough passes and distrupts the tropical feed. This sends a weakening cold front down the coast but only light precipitation is forecast before the ridge rebuilds.
Models are in good agreement through the forecast period, so confidence is high in the evolution of the synoptic pattern.
There is some uncertainty between models with the weakening front late Tuesday and how far south the precipitation will spread. At this point the Canadian solution seems reasonable.