Lunchtime Update: What are the Variables?

Some snow is a near certainty for the DC area.  So what will local mets be freaking out about for the next 50-60 hours before the first flakes start to fall in the DC metro?

1. Storm Speed:  when will the first flakes actually fly.  Of course, this has monster implications in terms of local commuting (just think if the snow starts at 3 PM on Friday...can you imagine the traffic issues?) and in terms of having the road crews ready to get rid of the snow once it falls.  Models tend to forecast storms moving too quickly at first so local mets are likely expecting things to start a little later than modeled.  For us, that would be sometime Friday afternoon.
2. Storm Track:  this is really the big deal...the difference between some snow, lots of snow and biblical snow.  And here's where the models are still disagreeing.  Some indications are that sleet could mix with the snow here in the DC area for a period of time on Saturday.  This would cut our accumulations from "crippling" to "significant".  There are currently models that suggest 8-12 inches because mixing takes place and others that suggest no mixing and totals more in the 18-24 inch range.  This will be the hardest thing to forecast and may really only become clear as the storm begins to increase in power on Saturday.  Obviously, there's a big psychological difference between 8-12 and 18-24 but there's a pretty big operational difference between 8 and 24.  8 inches is an average "big" snowfall around here.  2 feet is crippling for airports, roads, etc.  I'll be using the models as best I can to figure out what the final track will be.

Right now, significant snow is still expected, mixing could become an issue, crippling snow still possible.

More to come.