Snow Monday Night, then something bigger brewing later in the week?

It is finally time to pay attention to the possibility of accumulating snow in Lake Orion, as we will likely get a quick inch of snow tomorrow night, and a decent shot at getting our first notable accumulation of the 2009-10 snow season with a storm system later in the week.

First, I'd like to give a quick mention to a system tomorrow night that will move through and more than likely give us our first measurable snowfall of the year. It's not going to be anything too big - just a quick half inch or inch of snow ending by sunrise Tuesday morning - but it's still worth mentioning as it will be the first measurable snow of the season.





More notable is going to be a system that will affect us late Wednesday Night and through the day on Thursday. There is fairly good consistency among the different forecast models w/ regards to the track of this system, considering that it is still 4 days away.

Take a look at the forecasted position of this system Thursday Morning from 4 different forecast models (from top to bottom, the GFS, ECMWF, GGEM, and UKMET). They all support a track along or just west of the spine of the Appalachian Mountains. Personally, I prefer a track just west of the spine as I think it would be unreasonable to expect the northern stream trough to phase (combine with) the upper level low in the Southern U.S. so late that the track would be up the spine of the Appalachians. (More on this subject two paragraphs down)









Considering a track just west of the spine of the Appalachians, I would say it is fairly reasonable to expect that we will get some accumulating snow on Thursday. The projected track is a pretty good winter storm track for our area, but the cold air does not look to be in place until after the precipitation starts. Therefore I would say it's reasonable to expect precipitation starting as a cold rain on Wednesday Night before turning over to snow Thursday Morning and dropping a small to moderate amount of accumulation before departing the area Thursday Afternoon.

This is a fairly advanced subject that is more than what is usually covered on the evening news, but I figure it's in my best interest to point it out anyways, so I will say that one thing to note that could potentially change the track is that there is a "northern stream" trough that will phase (combine with) an upper low pressure system across the Southern U.S., giving us our storm system. Currently, this is not expected to happen until Wednesday Night. However, if this phasing happened earlier, it would also happen further west, and the storm system would thusly track further west, which would likely give us more rain, with a later changeover to snow, and therefore less snow accumulation. If it does appear that the systems will phase together earlier, I will mention it in a future post and adjust my forecast as such.

However, the bottom line is that I currently expect a few inches of accumulation with this system. It doesn't have a very good shot at giving us a snow day, but it has a decent shot at being our first notable accumulation of the season.