The 50/50 low comes into play when forecasting weather in WNC and across the Southeast periodically. Its occurrence allows cold air to rush towards the East Coast. But what is a 50/50 low? The 50/50 portion refers to the location geographically where the low pressure strengthens.. Thus, 50N & 50W are the latitude and longitude of where the low typically comes to fruition. This is around the Newfoundland Province of Canada. Below you can see a depiction of a model that develops a 50/50 low, and how that helps aid cold air in reaching the Southeast.
On occasion, a low pressure will develop near the Mexico/Texas border, and that can produce wintery weather in WNC, and even other portions of the Southeast. When forecasting for the long range, the consistent presence of a 50/50 low manifesting indicates that there is a high probability of below normal temperatures flooding the East. As this cold air meets warmer air, precipitation develops. Depending on how strong the cold air is, and where the high pressure to the north moves determines how much, if any, wintry precipitation falls in the South.