Finally, the event to break our snow drought is here

With the massive storm that is bearing down on DC, Baltimore, and Philly this weekend, it's the perfect time for the next storm to sneak under the radar and affect us...

Finally, for the first time in a while this winter, it appears that two systems will fully phase, allowing it to track further north than previous systems, and therefore affect us. The forecast models are in strong agreement on dropping an upper level low down from the Hudson Bay area and phasing it with a southern stream wave. This full phase will allow this system to track further north than the last two systems, despite another energy transfer occurring. This time around, the primary low pressure system will likely track from Mississippi to Michigan, before transferring energy to a secondary low that will move up the east coast.

What this means is that we will finally get some snow. And probably a decent amount of it, at that. The last four runs of the GFS model have been consistent in putting out a decent amount of precipitation for our area. Other models, such as the ECMWF and GGEM, are in agreement with our area getting a decent amount of snow out of this system.

Exactly how much snow we will get with this storm remains highly up in the air. If the low pressure system tracks directly over us, we will get dryslotted after the initial band of snow, which will cut down on accumulations. That was what the forecast models showed earlier, but they have trended a bit to the SE, putting us in the deformation band (heavier band) of snow, which would maximize our accumulations. The former is the worst option and the latter is the best option. The middle of the road option is that the low tracks even further to the SE, putting us out of the deformation band but also out of the dryslot. For the first time in a while, I can say that a large NW shift is fairly unlikely with this storm.

Likely helping us out with our accumulations will be favorable snow-to-water ratios. The typical snow-to-water ratio is 10 inches of snow for every 1 inch of water that falls, referred to as a 10:1 ratio. With this storm, ratios may start around 10:1, but will increase throughout the storm as cold air gets pulled into the storm, resulting in higher accumulation totals. (As a basic example [this won't necessarily be exactly what happens with this storm], if we got .5" of water falling with 10:1 ratios, that would result in 5" of snow. .5 of water falling with 20:1 ratios would result in 10" of snow.)

So, depending on the track of this storm, I could see anywhere from as little as 4" of snow (if we get dryslotted) to as many as 10" of snow (if we get the deformation band) falling in our area. As we get closer to the event, accumulations will obviously get locked in more than they are now.

Finally, on to the snow day chance. This will likely be a long duration storm, starting around noontime on Tuesday and ending sometime Wednesday morning. Currently, I'm focusing on Wednesday for the best chance of a snow day with this storm. For being 5 days out, I'm liking the chances of a snow day on Wednesday. For one thing, the timeframe is favorable, as it will still probably be snowing Wednesday morning. For another thing, considering the fact that it's February and we haven't had a snow day yet, I tend to feel that 5" or more will get us a snow day at this point. I also tend to feel that our area will probably get 5" or more with this storm, but at the same time, I recognize the fact that a lot can change between now and Wednesday, so I will conservatively put the initial snow day grade at a "C" (50/50 chance, things could break either way as we get closer to the event). I'm really liking this storm though.