The alert means there is an increased health risk to vulnerable people.
Up to 5cm of fresh snow was possible after wintry showers moving into the south of the region, most likely on higher ground, the Met Office said.
A yellow warning means severe weather is expected and it could cause disruption
A spokeswoman added: “Icy stretches are expected to form on untreated surfaces during Thursday evening and overnight into Friday morning as temperatures drop below freezing, especially following any showers.”
There was some disruption earlier in the week caused by the country’s first snowfall of winter, which affected public transport and roads across the North West.
The Met Office has advised people to check road conditions if driving or bus and train timetables.
The affected areas are: