Snow in the Southeast 2/16-2/18?
The question has been posed and the models have answered.
First post of this blog and I would like to say thank you if you are reading. This will be a bit more of a technical and delve more into the longer range than the Northeast Georgia Weather Information page on Facebook does, plus I will be covering all of North Georgia instead of a having a specific emphasis on just Northeast Georgia.
Lets get started with the topic of this first post which happens to be snow. In the southeast. Next week. Certainly this is a long range forecast so take it with a grain of salt, but I am growing more confident in a storm next weekend.
This won’t be the first storm to affect us next week. In fact, it will be the third. The NWS has issued a Hydrology Outlook for the first of next week when 2-5″ of rain could fall across the area (Mon/Tue). Below are forecast totals from the 18z run of the NAM for the next 84 hours, followed by the GFS through Wednesday.
The next system moves in for the Valentines Day period (Wed/Thu) and we could see some snow out of it on the backside but surface temperatures look to be a bit of a problem and the best moisture will likely be gone before the colder air gets here. However, as this system accelerates up the east coast (possibly bringing even more snow to the NE) it will drag in some very cold air behind it ahead of the next storm system swinging in right on its heels. Needless to say we are headed into a very active, dynamic pattern that has big-time potential to produce something wintry. First lets take a look at the 12z European WRF model. This is the 500mb geopotential height valid early morning of next Sunday. As you can see, there is a strong closed low across central/southern AL/GA with the associated surface low shown in the next photo just off the SC/GA coast.
Prior to this point in the run, the model shows the low develop and strengthen in the gulf, dragging down a lot of cold air and bringing snow nearly to the gulf coast. Accumulations range from a 2-6″ across all of MS and most of northern/central AL/GA into SC and NC. This is the perfect track for a system to produce a lot of snow for a lot of people, and the Euro ensembles seem to back up this operational run with the ensembles showing a deep eastern trough supportive of this type of system. Now on to the GFS.
The 12z run of the GFS today developed a low similar to the Euro’s although it tracked farther south bringing some snow to only parts of central GA and into the Piedmont of SC. The odd-hour 18z run showed a much more Euro-like solution with the low coming in farther north allowing northern/central MS, northern AL, extreme north GA, and all of TN to really cash in on some big totals as seen below.
Glancing over the rest of the models, there is a general agreement of a storm in this time period, and most global models are developing a pattern conductive to such a storm. Ultimately what you want to get snow in the SE is a tall PNA (Pacific-North American) ridge right on the west coast with a negative west-based NAO. The Euro and its ensembles are really honking at both of these things through most of next week as well as the GFS/ensembles, and the daily SOI (Southern Oscillation Index) has plummeted again which will certainly help to keep storms rolling through the area on a regular basis for the next probably several weeks. In addition, the dynamic models and official forecast all move the MJO (Madden Julian Oscillation) through phases 1/2/3 which are all historically conductive for an eastern trough and below normal temps with above normal precipitation.
This is still a week out and a lot can and will change, but I am growing slowly and slightly more confident in a big storm for someone in the SE next week/weekend.