Wednesday, March 8, 2017 9:59 PM

Weekend Snow Update–Trending South

Christopher Nunley

Here is a brief update on the weekend system that may bring snow to parts of the Midwest, Tennessee Valley, Carolinas, and Mid-Atlantic. Confidence is increasing that these areas will see snow over the weekend, and the latest numerical guidance has trended south with the snow over the past 48 hours. This means the Tennessee Valley and parts of the Carolinas are now in ‘play’ for snow. So what’s the setup?

Initially, a cold front will move through this region on Friday. This will provide the cold surface temperatures necessary for wintry precipitation. Behind the cold front, a potent shortwave will dive into the Southern Plains and eventually move into the South. This shortwave appears it will merge with another piece of energy moving out of Texas to form a surface-low. This surface-low will develop somewhere across the Gulf States, probably Mississippi/Alabama, which will aid in wrapping cold air into the precipitation. The evolution of this low and track are crucial in which areas see precipitation, how much precipitation areas receive, and which areas see snow. The low will trek towards the East Coast by Sunday. So what’s the timing?

The initial shortwave diving southeast across the Plains will aid in snow for parts of the Plains and Midwest late Friday into Saturday. The snow chances will then increase for the Tennessee Valley on Saturday, and the Mid-Atlantic and Carolinas late Saturday into Sunday. What are the uncertainties?

The evolution and track of the low are uncertain at this point. The strength and tack are crucial because it will have large implications on what type of precipitation areas receive. The vertical temperature profile is uncertain at this time, too, as well as an warm-nose that may develop. If the low rapidly deepens, a strong warm-nose could evolve. Snowfall accumulation amounts are also uncertain at this time. There is high confidence in accumulations, but not exact amounts at this point. Marginal surface temperatures and the sun-angle of March could allow for fast melting in areas that do not receive heavy snow.

Again, this is a few days out and a lot may change. This map below shows which areas have the best chance to see wet snow. Please keep checking back for updates!