The BIG storm: What we know..... and what we don't know??

Social Media has been blowing up all day about the POSSIBLE big storm. Let's break down the details with What we know...and what we don't know??


What we know!

1. Cold Monday and Tuesday where temps don't get above Freezing most areas.
2. We will have a storm Thursday into Saturday Time Frame.
3. I expect Lynchburg, Danville, Roanoke and Blacksburg to have at least an inch of liquid fall (Could be snow, ice, rain)
4. Starting time could be as early as 9pm Thursday evening far western regions and as late as 9am Friday far eastern regions.

What we don't know??

1. Snow amounts. Social media will be flooded with maps from XYZ run of whatever model. There are so many issues with them I don't know where to start. 5 days out, we don't know yet. Remember, now we look broad and get specific as the event gets closer.
2. Exact storm track.. This is HUGE and ties into number one. Remember we want to be on the cold side of the low. This means the north and west side.. the model runs that take the low into Kentucky are NOT great for our region. My guess is a somewhere into Georgia, reforming near Myrtle Beach, but that's an educated guess. If a primary low drives UP into Kentucky, we are icy and rainy.
3, Exactly how much cold air will be in place and then reinforcing during the event. Antecedent cold air is very important for a big storm. However, getting cold air funneled in as the storm progresses is also important. Remember our Presidents day storm last year. We had snow and 12 degrees and it changed to sleet-- we had no cold air reinforcing the mid levels. Model data has trended a bit colder and I think this may continue for another day.


Wow, you said a lot of nothing...

YES I DID! 

I can speculate a little. This is speculation and will change. My goal will be to create a framework and then fill in the fine details as the event gets closer.

1. I believe the models will trend colder over the next day and give a decent idea of what to expect. The warmer models have stepped towards the colder models and the colder models conceded a few points and it's slowly coming together. The ensembles (same model run at lower resolution with some intentional changes added to weed out biases) have been more south and colder than the "operational" runs.

2. Once the models bottom out cold/south track wise- we see what corrections will be made back north and warmer.

3. Basement and ceiling for main locations...

Roanoke/Blacksburg- Lumped in together because this has some marks of an I-81 special. The floor of snow and ice accumulations is 2 inches with a ton of ice and freezing rain mixed in. The ceiling is a storm of over a foot or maybe more. Their odds of over a foot of snow is HIGHEST at this point. I'd estimate 40% at this point.

Lynchburg-  Basement is the same 2 inches of sleet, snow and slush. Ceiling is also over a foot of snow or more but the odds are much lower at only 25 %. Their 40% number is 8 inches.

Danville and Southside- Basement is a coating of slush and sleet, ceiling is also a foot but odds are down at under 10%. Their 40% number is 6 inches.

As we move closer, I will update and refine to give more details. We will be moving from broad to specific.
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I'll continue to live tweet thoughts and progression during model run times. Feel free to retweet or ask me questions.