Weather! Some additional thoughts on this weekend

As Roanoke.com’s Kevin Myatt put it, “We’re entering that period of time when the hype can outrun the reality for a potential winter storm.” I’ve had the chance to digest another 12 hours’ worth of model outputs, and I’m just as ready to pull my hair out now as I was then. (I apologize if […]

December 23, 2010; 2:56 AM • by Weather Dan

As Roanoke.com’s Kevin Myatt put it, “We’re entering that period of time when the hype can outrun the reality for a potential winter storm.”

I’ve had the chance to digest another 12 hours’ worth of model outputs, and I’m just as ready to pull my hair out now as I was then.

(I apologize if some of the discussion seems a bit confusing at times; there’s an Ask Weather Dan on the models coming soon!)

One of the advantages of waiting to make a decision on a system like this is that we get to bring additional model solutions into the equation. The North American Model (or NAM) only provides a solution out to 84 hours. Up until now, our event was still too far out for the NAM to be totally helpful; now we’re almost entirely within that 84-hour window from the initialization time of the model to be able to get some useful information about the timing and track of our low.

When I left you this morning, the biggest question was about model consensus – would we see a track shift among the different models to bring them all in line with a certain path? Would the Euro stick close to the coast? Would the GFS continue bringing the low out to sea?

We got a pretty good answer from the remainder of Wednesday’s model runs. The Euro has crept away from the coast enough to put a big dent in some of the historic snow totals that have been mentioned so far. The GFS on the other hand, has decided to track back to the west fairly significantly. It’s not as close to the coast as the Euro still wants to bring it, and the GFS has now become the faster of the two solutions. Throwing the Nam, the GGEM (a Canadian model), the CMC (another Canadian model) and the UKMET in the mix, we get a consensus that still keeps a majority of the precipitation offshore.

It’s important to highlight here that the European model solution is still just as possible to occur as any of the others, and while though I’m not giving it a significant amount of attention here, there’s still the chance that we see near-historic snowfall from this system.The biggest strike against this possibility right now is that the Euro is the only model that supports anything of this magnitude so close to the coast.

With regards to timing, the peak hours for any precipitation are looking to be between Saturday afternoon and Sunday evening, depending on exactly where you are. Of course, this also depends on whether or not we’re going to actually SEE any precipitation, which is still quite the question.

My hope is that the we’ll see further agreement among the major models today. They all seem to have a handle on some of those delicate meteorological factors I mentioned, and so now the question becomes a matter of precipitation intensity, timing, and location. In other words, the same three questions we’ve been struggling to answer.

December 23, 2010 2:56 AM 1