While this article will not be nearly as extensive and detailed as the one from the other day, I did want to do a brief update on the latest trends, and I will have a much bigger and detailed update on Thursday night.
The biggest issue right now is still trying to pin down the exact track of the low pressure system that is going to develop along the Gulf Coast, which will then move off the Southeast coast (and potentially up the coast some, depending on certain factors).
There are some differences on strength of a northern stream system that will be moving over the Great Lakes region. The other uncertainty remains to be with timing of the vigorous shortwave feature that will be moving into the West Coast and triggering the development of the winter storm that will eventually impact the Southeast.
The models are beginning to come into better agreement, however there are still some differences on the northern extent of the moisture, which makes this forecast still particularly challenging.
The European model isn’t too bullish on bringing adequate moisture into the northern half of Mississippi and Alabama, while the GFS model is somewhat more aggressive. This is one area that is going to have to be watched still, and the threat zone might have to be moved some south. The map that Christopher Nunley put out on Firsthand Weather last night is still a good indication of where wintry precipitation could fall. The big question right now for that region is how much precipitation will move into the region and how heavy it will be. We might actually have a better handle on that by tonight.
The low pressure system is really going to ramp up as it begins to move off the Southeast storm. This could actually be a big winter storm for the Carolinas, and I expect that one stretch will get at least over 4 to 6 inches of snow. The system is going to deepen as it enters into the right entrance of a jet streak that will be located along and just off the Mid-Atlantic coast. The atmosphere should be primed for the strengthening of this cyclone. Northern and central Georgia remains to be a bit of a question mark too because of uncertainties on northern moisture extent. The Weather Prediction Center has gone particularly aggressive with snowfall potentials over northern Georgia and far western South Carolina for Friday night, so it is a region to watch closely. All regions that were mentioned in my last article need to still remain alert. Depending on later trends, I may have to add parts of the Carolina beaches in the threat zone but will hold off on that until tonight or tomorrow.
Figure 1: Forecast for Friday and Friday night courtesy of the Weather Prediction Center
As you can see below, both the latest GFS and European call for a sizable winter storm across the Carolinas, but pinning down the regions that will receive heaviest snowfall amounts is challenging and honestly impossible at this point.
Figure 2: Latest snowfall projections from the European model through Saturday night
Figure 3: Latest snowfall projections from the GFS model through Saturday night (important note: totals are likely elevated in southernmost regions due to sleet/freezing rain possibly skewing totals)
A potentially significant winter storm is looking more likely for the Carolinas. I am also keeping the northern half of Georgia and southern portions of Virginia in a high risk zone for this event, too. I expect some impacts for north-central portions of Mississippi and Alabama, but that is very much contingent on moisture. Extreme southern and extreme eastern parts of Tennessee could see some impacts, too. Christopher Nunley is covering the potential impacts from this system west of the mentioned areas, and Rob Millette is going to cover regions north of that zone.
Figure 4: The probability that a region will get at least 4 inches of snow (blue circle indicates probability greater than 10%, green circle indicates probability greater than 40%)
One last note. . .a region from the Central Plains over to northern Tennessee, Kentucky and extending into parts of Ohio, West Virginia, Virginia and to the coast (I didn’t name all regions) could get some snowfall tomorrow into early Friday with possible accumulations from a much weaker system ahead of the main storm system. Be sure not to get the two systems confused!
Again, these are just some quick thoughts, and I’ll have a much more extensive update Thursday night including timing, additional details on precipitation type and maps.