The Euro was a madhouse-- with literally 15-25 inches of snow from Roanoke to Lynchburg with maybe close to 30 inches in places NW of Richmond.
Don't take this literal-- at all, yet. Potential has certainly grown and we could be staring down a potentially historic weather event. We've moved away from a full phase event where two vort maxes merge near our region and more towards just a strong closed upper air low being pushed south of our region and slowing down due to the stronger blocking. The low gets vertically stacked which means the surface low and upper air low are on top of each other and it's a beautiful event.
Here's a link to an article about the Ash Wednesday storm. This guy was up towards Massanutten, but it conveys how intense that storm was. This storm, 51 years later, would fall on Ash Wednesday. Lynchburg had almost 18 inches of snow from this event that stalled off the VA coast for day and was one of the costliest storms ever in terms of coastal beach erosion.
http://www.glenallenweather.com/links/digest/greatestsnow.htm
What could go wrong??
We are still 100 hours away. There will be changes in the final solutions.. Here's a quick guide to ways to sabotage our winter event.
1. Temp profiles are not horrible, but March with sun and no cold air advecting. In our region of the state, with a late afternoon Tuesday start, it may start as rain. Models are tad warm at the surface and this is always a concern. Taken literal, the EURO has rain in Danville for HOURS after it's snow in Lynchburg and Roanoke. Models TEND to be a bit cold at this time frame in general. So, we could get the BIG event, but too much rain that limits it.
Further, if we don't get quite as heavy stuff--we could get what many refer to as "white rain" where it snows for hours but doesn't lay. The
Once we get under the "deformation zone" we should get plenty cold-- but deformation = banding. I've mentioned before how banding can be hit or miss. This could start and end as rain-- once the storm occludes, it quits making cold air.
2. The upper air low doesn't dig as much. This would cause both temperature issues AND less precipitation. From my experience, you want the upper air low to travel about along 1-40 in North Carolina to max things out here. This is a very strong low and moves from North Central South Carolina NE towards let's say Kill Devils Hill on the Outer Banks. That's an incredible track. Until we hit the 72 hour mark, I'm not sure this willing to bet on a track like that. If it slides NORTH,we are warmer and a less hours under the "heavy" bands. This issue comes in if it DOESN'T dig down into South Carolina- what if it's only North East Tennessee. This can't be ruled out yet.
3. It doesn't slow as much-- Very possible. Spring is notorious for slow moving upper air lows-- and I'd love to see it but this looks extreme on the EC. A faster solution could yield a nice event, let's say 6-12 inches, but not historic.
4. Snow ratio's are horrible. On the January 17th event this year. Near my place on Timberlake rd, we had close to 4 inches from about .7 liquid. So, it was close to a 5-1 ration. Normal ratio is 10-1 or so. Between warmer temps, slower spells that could mix with rain, even if we get the 2.5 liquid as modeled. Ratio's could be as low as 6-1. That would be 14-15 inches of the heaviest concrete snow you'd ever seen in your life.
Vegas odds-
1. Over 2 inches of snow 75%
2. Over 6 inches of snow 50%
3. Over 12 inches of snow 25%
4. Over 18 inches of snow 5%.
I'd love to show the vorticity maps I get from a vendor, but I'm not willing to risk that. However, here is a qpf map from another site I found on FB. It shows one of the 6 hour snap shots of how much precipitation falls in 6 hours. MOST of VA has at least .5, places in the east exceed an inch. The model has 2 time frames like this plus another not far off.
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