There have been a ton of questions flooding into the Firsthand Weather inbox about the potential for wintry weather this week across the Southeast. Let’s address this fluid forecast that has many questions. We are closely monitoring the potential for wintry weather this week across parts of the South & Southeast. There are two shots for a wintry mixture across the regions. The first shot at a wintry mixture begins the first-half of Thursday for far southern & eastern Tennessee, far northern Mississippi, far northern Alabama & northern Georgia. A modified Arctic airmass will move south through the region late-Tuesday into Wednesday allowing temperatures to quickly tumble.
A general uptick in precipitation begins late-Wednesday as two upper-level disturbances approaching the South. A southern-stream shortwave will move in from the southwest at the same time a northern-stream trough will drop toward the southeast. This will help aid in the development of a large shield of precipitation across the South. This shield of precipitation will advance east overnight Wednesday into Thursday. As the precipitation advances east, an Arctic high will build in from the north, helping to reinforce the cold air. With this reinforcement of cold air, will be extremely dry air throughout the entire column of the atmosphere; acting to help shut down precipitation chances. The main question: is there enough moisture left as the cold air moves in to support wintry weather? This is the classic race of moisture vs. cold air. It does appear there may be enough moisture around to allow a brief rain/snow mixture across far southern Tennessee & far northern Mississippi early Thursday before spreading east into eastern Tennessee, far northern Alabama & northern Georgia later in the day on Thursday. There are still a lot of questions so it’s too early to address accumulations. With that said, it appears no major accumulations are expected.
The second shot for snow exists farther east across the Southeast. The same upper-level disturbance will move east throughout Thursday. This trough will allow a surface low to develop just off of the South Carolina coast. This low should be close enough to the coast to pull moisture into the Carolinas late-Thursday. At the same time, the Arctic high will build in, allowing cold air to possibly undercut the moisture. One tricky detail is just how much the terrain slows down this reinforcing cold airmass. Arctic airmasses are dense, thus shallow, meaning terrain can drastically slow down the movement. This could protect the Carolinas from wintry weather. Right now, however, it does appear enough moisture will be in place as the cold air moves in to generate a rain/snow mixture across Upstate South Carolina & North Carolina. It is too early to forecast accumulations for this area.
To sum it up: yes, there is growing concern that parts of the South & Southeast may see snow Thursday. The best chance will be across far northern Mississippi, far northern Alabama, northern Georgia, far southern & eastern Tennessee, Upstate South Carolina & North Carolina. It is too early to address accumulations at this point so keep checking back for updates.
The images provided should be used as a tool to evaluate the timing & expanse of the precipitation shield, and is simply output from ONE model. Other models are showing a similar output. Keep checking back as this will be updated as the event nears.