Updated for New Model Look; Big Snow On the Way Oklahoma-Virginia

***Added a comment based on a look at the new BAMS 3KM Model run see below in (*)***

Confidence is on the high side that a major snow event is ready to take place from the Panhandles of Texas to Virginia. A wide swath of 6 to 12 inches will be expected with some spots may see up to 18 inches. The heaviest is expected across the Panhandles of Texas/Oklahoma, northern Arkansas/southern Missouri and the mountains of Virginia/North Carolina and southeastern Kentucky.

Still have questions has to how far south icing problems will be a concern. Could it make it as far south as U.S. 72 in Alabama and U. S. 278 in Mississippi? Maybe. I know that doesn't help out much but confidence on southern boundary of icing remains tough to pin down as of now. ECMWF (Euro) model is remaining the furthest south with the main surface system and in turn allows the freezing line to sink further south. The US models are both trending back further north as is the Canadian but I am not convinced which will be correct yet. My big concern is the nature of Arctic air.

The airmass sinking south through the eastern U.S. is of true Arctic nature. Cold air is denser than warm air. The colder the air the more dense it is. This air will be cold and dense, although it will modify a bit on its southern track the next day or so. I am concerned that once temperatures reach 32 or below it will be very difficult to rise much again for those of you in northern Mississippi through northern Alabama into northern Georgia. In addition, with the surface low forecast to remain along or south of I-20, and possibly as far south as the northern Gulf coast, the surface winds will be east to northeast and will only be advecting (or advancing) the Arctic air into the region and not the warmer gulf air. While a loft into the atmosphere, the warm Gulf air will glide upward over the top of the cold air at the surface. This sets up the potential for freezing rain to form. The exact location of the freezing rain versus the plain old cold rain will strongly be determined by the eventual track of the surface storm system.

In addition, could there be convection or thunderstorms embedded into the precipitation shield? The answer is yes. Already today, thunderstorms are occurring along the cold front in Texas with temperatures within a couple degrees the freezing line, in both directions. This could produce a period of thunder freezing rain or sleet. However, I believe most of the convection will become confined over time to the I-20 corridor, south of the potential freezing zone Friday into Saturday.

I am going to take another look at things later this evening and provide another update. I hope my gut feeling is stronger.

FYI, I still would not encourage travel along and within 50 miles of the I-40 corridor from New Mexico to Virginia through Saturday. New Mexico DOT & the Texas DOT have already CLOSED portions of I-40 due to snow. If you are going to brave the weather, here are some links for road information for certain states:

• New Mexico
  
• Oklahoma
  
• Texas
  
• Kansas
  
• Missouri
  
• Arkansas
  
• Tennessee
  
• Kentucky
  
• North Carolina
  
• Virginia
  
• Illinois
  
• Alabama
  
• Mississippi
  

***For those in northern Mississippi and northern Alabama, I just looked at the most recent high resolution (3-KM) BAMS model (Baron Services) run and it has remained consistent with a burst of convective precipitation changing over to a burst of heavy snow late tomorrow afternoon. For the TN Valley it forecasts this occurrence between about 5 and 7 pm. It is again just one of many possible solutions but it is the highest model run available for the TN Valley and it has remained consistent for the past several days with this type of solution. If it would be correct, tomorrow's evening rush may be a bit tricking. For those in the Valley, tune into tonight to WAAY 31 for the very latest forecast and depiction of this model.***