As I write this column late Monday afternoon there are uncertainties in the next 48 to 72 hours as our cold spell evolves. Cold air east of the Rockies and in Canada that we have been chatting about the past week is on the move southward and most importantly, slightly westward.
At 5 p.m. Monday temperatures had fallen to the freezing point in Bellingham with dew points in the upper teens, which is a sign of cold modified arctic air. I always say when we begin a situation like this, watch the dew points.
Further east in Omak, it was 25 degrees, the dew point was only 3 degrees above zero — dry air. I expect the leading edge of cold air will cover all of Eastern Washington today. It will deepen in the Columbia Basin with sharp increases in barometric pressure.
Eventually east winds will transport the leading edge of the cold and dry air some time Wednesday into Clark County. As winds pick up out of the Fraser River Canyon into Bellingham, the cold air will seep west and south to cover the Washington coastline. If the cold air settles in long enough the coast will have its coldest low temperatures of the season.
