The hype of Sandy--

In the era of easy access computer models, about everyone heard of the "possible" mega event In short, a tropical system has formed well south of Jamaica and will move north towards the Bahamas. At the same time, a STRONG STRONG arctic front approaches from the west and a block forms to the north in NE Canada. As a result, the upper energy grabs the tropical system and quickly transfers it to a non tropical storm and as the cold air undercuts and HEAVY snow falls over much of WV, VA, MD and PA. Pretty wild stuff on the modes and about 99.8 % unlikely. It would be a once in 500 year even if anything remotely close happened. 

My long time reads now I love eye candy-- and here is the snowfall map based on 10-1 ratio over the area.

Pretty extreme map-- year, that is 48 inches over that inner circle and the 1-6 inch line is south fo 460. Because of the dynamics of the system, it was near Virginia Beach and ends up near Lake Erie per this model run. Amazing thing is as the storm moves NW our cold air is riding in on south and southwest winds. 

I'd say the odds of a BIG event is likely, but nothing remotely close to this. It's rare, but snow on the backside of Hurricanes does happen as moisture over runs or lingers behind as colder air comes in. There was an event in fall 2005 that had backside snow over central PA from a hurricane and I can recall another storm in the 80's. 

In summary, Sandy will interact with the arctic front and I imagine there will be snow and snow showers on the backside, but nothing remotely close to this extreme run. I think we will miss the bulk of the rain, have some colder temps and Mountain Snow showers after the cold front passes. (In Central and Western VA)

Take out the tropical part and the November 1950 is the closest event to what was modeled last night. NWS Blacksburg did a nice write up on this event in a newsletter last fall. There was a very tight gradient of snow to no snow where Roanoke and Martinsville had 5-6 inches and Danville and Lynchburg had a coating to an inch. 

http://www.erh.noaa.gov/er/rnk/Newsletter/Fall_2011/Fall_2011_Newsletter.pdf