Breaking down how we get big snow storms in Southwest Virginia

By Jonathan Kegges - Meteorologist

ROANOKE (WSLS 10) - Meteorologically known as cold air damming, in winter, the wedge can mean the difference from plain old rain to the "big one" when we have a storm coming at us from the south.

Rain, sleet, snow, ice. We have it all in Southwest and Central Virginia.

Because of our topography, the wedge has a big influence on what type of precipitation we get.

During summer, is brings us relief from the heat and in winter, it provides us with that classic setup for the big one, as was the case back in January.

High pressure over New England induces the wedge setup, which brings us a northeasterly wind and supplies us with that cooler air down the spine of the Appalachians from the north. That cold air gets trapped against the mountains and stays trapped until that area of high pressure moves away from the sweet spot over the New England states and changes our wind direction.

As the air runs into the mountains we get the upslope effect as the air has nowhere to go but up. The air rises, cools and condenses and we get clouds. Often times rain and drizzle accompany the clouds. If it's cold enough, we can see freezing drizzle, freezing rain, and even snow.

So will we see a lot of that this winter?

On Friday at 5 p.m. on WSLS 10, we'll let you know how much snow you could potentially see in your backyard this winter.

Copyright by WSLS - All rights reserved