Winter Storm Update Saturday Jan 8

The latest trends continue to be stronger with the upper low coming into Texas early Sunday. One of the reasons for the uncertainty in amounts is the degree of decay of the upper low, and as it turns out, like 3 of our previous big upper lows this Winter, the RUC model continues to maintaining the strengthening all the way into Texas and all short range models today have caught on to this idea, yet still decay the strong Vort as gets drawn northeastward across the Deep South Sunday night and Monday.  The SREF model continues to inch the higher amounts northward each run, and looking at Satellite, its obvious the Northeast system will be pulling out and the southern system is going to close off again. Like most systems so far this Winter, the models are underforecasting the precip amounts and the omega west of the Appalachians. It now appears Tennessee will get fully into Snowfall underneath the right entrence of the divergence and tremendous southern 5H advection ahead of the slowly decaying and spreading vort. This will allow an area of 2 maximums in precip, one along the gulf coast associated with the weak Gulf low, and another along the path of the PVA crossing the Mid South, which likely will be very strong until atleast the central Carolinas, when it is fully absorbed into the (by then) Georgia developing coastal.  The Carolina coastal off HAT could intensify rapidly with the ushering trailing vort, but where it occurs exactly will make a big difference on throwback snowfall in eastern NC and then up the East Coast by early Tuesday. Its too early to say if the storm turns into a major Midatlantic and Northeast snowstorm.
One question mark regarding dynamic cooling for northeast Texas and northern Louisiana and southern Arkansas, the Arklatex region. The strength of the vort there may overcome marginal temps, and combined with strong lift and dynamics, a suprise heavy snowfall could occur in and around Dallas Fort Worth or somewhere east northeast toward the Arklatex.  I expect enough lift and high snow ratios early  on to deliver a large 6" snowfall in parts of northern Mississippi and around southwest Tennessee, and again in and around northern Georgia or the Southern Appalachian region where very cold air will reside for the bulk of the lift and moisture. There's still question how much snow falls into the piedmont of NC but all models have been upping the amounts there, yet still have a relative minimum north of Charlotte, however that may be an error due to the models not recognizing the strength of the fading 5H system that still will be strong and has weak shortwave ridging across an open omega field. In fact, with northeast and easterly flow from the surface to 950, and southeasterly flow at 850 for the duration, some foothills enhancement could show up in meso banding around the Upstate of South Carolina and western NC between Charlotte Hickory and Anderson. Unfortunately, we can only predict that type of occurrence when its imminent.
After the snow ends for northeastern GA and much of the interior of the Carolinas, residual moisture will be wrung out in the form of freezing drizzle for a 6 hour duration or even longer. The snow pack should be crusted over with a glaze over a very large region of Piedmont between Atlanta and Raleigh.  For the eastern Carolinas, the timing of good moisture and the retreating cold air aloft make it a race as to how much snow occurs before the changeover, and all models are still close to call with the complicated southern stream possibly being reinforced late Monday night or early Tuesday, and incoming colder air aloft.  If the Upper low holds stronger as I suspect, the snow will streak further east than I have shown and cover much of NC in snow, but its too uncertain to forecast how much with any certainty further east toward the Coastal Plain. Sleet could actually be a bigger accumulator than snow the further east yet get in the Carolinas because of the loss of low 850 temps and a possible resurgance of lift and moisture. Further south into central Georgia and east Central Alabama to central South Carolina, a significant and in some cases, major, Ice storm could evolve.

Local Forecast: For the Upstate , Western NC,and northeast GA:

Snow spreading into northeast Georgia late Sunday evening around midnight and overspreading the western Carolinas by daybreak Monday. Temperatures holding in the 20's Monday and the snow changes to sleet briefly then freezing drizzle very late.