ALBUQUERQUE – Forecasters say back-to-back storm systems will pass across New Mexico this week, bringing showers and thunderstorms starting late Tuesday and “treacherous” travel conditions in mountain passes by Thursday.

The National Weather Service says the first system will spread northeast through the state late Tuesday night and Wednesday. Snow levels will fall to near 8,500 feet by Wednesday evening.

The second system will move through the state Thursday, with snow levels as low as 6,000 feet and more than 12 inches of snowfall in higher terrain.