Alright, let's get right down to business!
There are two parts of the southern stream storm system. We have on in the FL area and another area of scattered precipitation in the Tennessee Valley.
The TN Valley precip looks to be what could bring us a few snowflakes during the day today. Even a snow shower is possible. We'll see the two areas of precip phase over the Valley tonight once the other area moves up the eastern seaboard today.
What we have to watch for - again - is getting in the 'black hole' of no precipitation. Right now amounts look rather light. We could have minor snow accumulation (quick coating) from the TN Valley precip and then icing from the bulk of the southern stream precip - with very little leftover for when temperatures actually get above the freezing mark. I think we need to be on guard from the evening commute all the way through our Tuesday morning commute.
Unfortunately for meteorologists, this is a system that will be heavily "now-casted". Cold air damming situations tend to be more "now-casted" because models have a very hard time catching onto how long the cold lingers in the Valley before temperatures rise above freezing. In addition, we're dealing with another setup where there are two low pressure systems and we have to see how far west the precip extends with the system riding up the eastern seaboard.
I'd say until 8 or 9pm, the main precip type will be snow - afterward, the warm air moves in aloft which could bring a brief period of sleet - but the majority of us will see freezing rain from 11pm-5am. At this point, temperatures will start rising above freezing from south to north, that's why the best chance of ice accumulation is in the northern Valley.
If we see mixing of precipitation types - snow, sleet & freezing rain - we'll see reduced accumulation because there isn't one dominant precipitation type to accumulate. However, total liquid accumulation looks to be .10"-.25" - how that breaks down into each precip type is much harder to say. I think we're looking at less than a tenth of an inch of solid ice - still enough to cause issues - some flurries and then plain ol' rain later in the morning Tuesday.
We definitely need some rain in the Valley, but this doesn't look to be the big one for us. Temperatures and wind flow need to be watched closely tonight into Tuesday morning to see how strong the damming is and how well it is holding up.
Of course there's Event #2 which will come into the area late Tuesday night into Wednesday morning. We'll discuss that more later today. One event at a time! Feel free to ask questions!