From the Washington Post
http://voices.washingtonpost.com/capitalweathergang/2010/12/white_christmas_odds_good_not.htmlScenario 1The southern storm is strong enough and passes close enough to bring enough moisture into the metro region to produce a light, accumulating snow event Christmas day into Christmas night. However, it does not combine with a disturbance to the northwest in time to produce big snows. The models supporting this scenario include the Canadian model and many of the GFS ensemble members, including the operational GFS. In this scenario, there would be a slight possibility the northern disturbance would combine with the southern disturbance in time to produce heavy snow over New England.
Scenario 2The southern storm is too weak and passes too far south to produce much more than light snow or flurries (if that) and/or dry flow from the north eats away at the moisture arriving from the southwest. It does not combine with the disturbance to the north for a big storm anywhere along the East Coast. Just a few of the GFS ensemble members and last night's UK Met model suggest this possibility.
Scenario 3The latest European run shows a huge storm for the entire East Coast, but on December 26 into December 27 as opposed to Christmas day. Essentially, it slows the progress of the southern storm allowing it to completely phase (or combine) with the northern storm. The result is a major snow/wind storm (blizzard) in this simulation. However, this model has a bias of being too slow with disturbances along the southern branch of the jet stream - so we'd like to see other models trend toward this solution before buying it. If this model were to move the southern storm faster, it would simulate a lot less snow (maybe not even any - as it might go out to sea rather than merge with northern storm).
Which Track seems suitable?
