The discussion below is a little technical and more wordy than the normal discussions I issue. This was created for a forecasting class at UNC Charlotte. It is for the snowstorm 2/12-2/14 and was written the evening of 2/11.
A significant winter storm will impact the Charlotte area during the next few days. Monday evening, a surface front was situated off the coast of SC and NC. A 1036mb high was situated over the northern Great Plains. This high will move east, and help funnel cold air into the region aloft as cold air damming occurs.
On Tuesday, models vary as to what amount of precipitation overruns the cold air and moves into our area. The NAM keeps most of the moisture south, while the GFS brings moisture into the whole region, with around a half of an inch of QPF. GFS appears to pick up on an area of upper level energy moving through, which helps enhance lift and cause the precipitation. BUFKIT sounding profiles support snow across the region, even while surface temperatures are a degree or two above freezing. Ground temperatures are still rather warm, so if precip falls tomorrow some should originally melt. However, it should be noted than extended period of snow could add up, potentially up to a half inch or inch of snow through Midnight Wed if the GFS is right.
On Wednesday, the big event takes shape with heavy precip amounts and an extended period of precipitation. Miller A storm track with surface low pressure forming in the Gulf of Mexico and moving up the coast. Precip should move into the area from the southwest as we go into early Wed morning. There is surprisingly good consensus in midday runs in terms of QPF, however, evening runs vary with the NAM being nearly an inch higher in QPF than the GFS. We’ll need to watch future model runs to see how QPF varies and how models depict precip type events.
In terms of precip type, the 18z NAM shifted freezing rain and sleet further west, with almost a five hour period of freezing rain Wed evening due to a warm nose at 900 to 850mb. If this happens, power outages would become an issue when you combine the potential for heavy snow and ice. The 0z NAM-4 also supports this icing potential. The GFS on the other hand keeps the primary precip type as snow, with only a brief period of freezing rain very early Thu morning. The inversion on the GFS isn’t as significant, and leads me to think it could easily be overcome due to heavy snow rates. Obviously, models have been flip flopping run over run and as I mentioned above in terms of QPF though, shifts in the track of the low will need be watched over the next 24 hrs as these shifts could be critical in determining what type of precip we see and how much.
Heavy snowfall accumulations look to occur regardless of icing. Afternoon runs of the GFS and NAM both displayed snowfall amounts around 7 inches. SREF plumes mean average is around 7 to 8 inches as well. The question is, where does the deformation zone set up? Where this heavy band of snow forms may have a large impact on totals. If the heavy band sets up over Charlotte, a foot of snow may not be out of the question. Taking a blend of models, and factoring in the potential for icing, I feel as if a 6-10″ range for snowfall accumulations in Charlotte is not out of the question, with the low range being if we see more icing and the higher end being if we see more snow.
Precip looks to continue into Thu, eventually tapering off late Thu morning as freezing rain or drizzle as the low pulls away to the northeast. High pressure builds back in for the weekend, with a few weak cold front moving through the area Friday night and Sunday. Precipitation at this time from those systems seems limited.