Not an easy forecast to make, so I am glad there are some days left to sort it out. The NWS has taken off the mention of snow in their long range forecast, but in their recent meteorologist discussion they stated: "CONFIDENCE IN WED/THU FORECAST IS LOW. BUT THERMAL PROFILE MAY BE COLD ENUF TO SUPPORT SOME SNOW MIXING IN...ESPECIALLY AT HIGHER ELEVATIONS WED NIGHT." Meaning, they are uncertain about how well their current Wed/Thurs forecast will fair given the uncertainty of the data. Before people get upset with the NWS, keep in mind that they are an agency with protocols in place to ensure standards in forecasting since they are the official forecast and many people depend on them. Also, they cannot make unsubstantiated predictions which may panic people necessarily. Therefore, their forecasts are more conservative. I on the other hand can be a bit more liberal in my predictions. So this is why the NWS may not always predict snow until the last moment, even though I, and others, have seen it for days previous.
All that said to make my point that even though the official forecast does not yet call for snow, the NWS has been trending their temps downward for the end of the week, and do appear to be extending the precip possibility a bit later into the week as well. What I currently see is a snow chance somewhere between Wed - Fri. But this is only a chance, and I am not as yet sold on this solution. Here are some concerns of mine:
1. Will the temps drop enough for the precip to turn to snow?
2. What will the exact position of the Low be? Currently the Low is predicted to ride along the coast. For a substantial snowfall we need the Low to move just off of the coast.
3. Are the ground temps cold enough to sustain accumulations?
4. Will the NAO go negative?
These are my top concerns, and unless they are answered favorably, we will be looking at some cold rain the end of the week. I will say though that the current data trend has the Low in a position where DC, Balt, Philly could see snow, leaving most of S. MD with either rain or nothing. But a slight shift of the Low to the east and we get a better shot at snow, even for S MD. That's if the precip and the cold air are in place at the same time. That is yet to be seen. The model data is all over the place, so I don't want to just look at that, but also recognize how our current surface conditions can effect what will happen. And the fact that Monday and possibly Wed will be unseasonably warm don't bode well for snow development Wed night into Thurs. Not to say it cant happen.
So, bottom line, I do see a possibility for snow later in the week, but am just not as yet convinced of it. I know many of you want a definitive, but I hope, through this discussion, you can appreciate the bind I am in. Give me another day or so and I will have more definitive language for you, whether or not the NWS picks up on this.
Follow me daily on Twitter (@wxmanmd) and I will update my Weather Phone as needed (443-470-9804)
