Winter Storm Warning for Whatcom County as storm promises snow, freezing rain
Whatcom County may have not had much snow during our recent Christmas storm, but they're going to try to make up a bit for it Wednesday evening.
An approaching storm is set to bring rain to much of Western Washington, but with lingering cold air in Whatcom County filtering in through the Fraser River Valley, the storm will begin as snow. But of more concern, the snow is expected to change to a period of freezing rain late Wednesday night into early Thursday morning, coating everything in as much as 1/4 inch of ice -- especially inland away from the water.
A Winter Storm Warning is in effect from 6 p.m. Wednesday through noon Thursday for areas including Bellingham, Ferndale, Blaine and Lynden.
Freezing rain will make travel especially treacherous with layers of ice possible on sidewalks and roads.
For everyone else, it's a simple rain event as the storm brings in milder air. However, Whatcom County is a special case because arctic air is still leaking into that region via a northeast wind through the Fraser River Valley.
At first, the lower atmosphere will be cold enough to support snow in that localized area, but as the air mass warms, snow aloft will melt into rain. But the arctic wind will keep the air near the surface at or below freezing, turning that rain into super cooled rain droplets that will freeze on impact, creating layers of ice.
Forecast models are uncertain when it'll warm up enough to change to rain on Thursday, so areas around there should plan on perhaps several hours of light freezing rain until the midday or afternoon hours -- again most likely away from the water like Sumas and Lynden.
A second, strong storm arrives on Friday but will be sufficiently warm enough that all lowland areas are just rain -- although the mountain passes are likely to get heavy snow.