We have a two-punch storm system coming in over the weekend that will bring another round of mainly rain in the valley (although a few snow showers Saturday is possible) and mountain snow (although a few mountain rain showers are possible Friday.) The first wave arrives Friday morning with snow levels that might start at the Lake elevation, but will likely climb to nearly 7,000’ by the afternoon. In Reno, strong southwest winds will keep us shadowed out for the most part, but some spillover showers could occur on the west side of the valley. The second and colder impulse comes through late Friday night, and snow levels will drop to near the valley floors on Saturday, although little to no valley accumulation is expected. Highs in the 50s Friday will drop to the 40s Saturday and Sunday before rebounding to the 50s with a drier outlook next week.
So how do you get freezing rain? In general (and perhaps obviously) you need to have warm air aloft on top of cold air at the surface… along with (again obviously) some rain. This can occur a couple of different ways. A warm front will always shove warm air up over colder surface air, and is a relatively common way to get freezing rain in the central plains states. Here in Nevada, these cold air inversions that we have been having can also trap enough cold air in the valleys to create freezing rain, although it is fairly rare.