You've heard about the massive snow totals in the Denver area but what can we expect in the D.C area. this weekend?
Black Hawk, CO - 28.5 inches Pinecliffe, CO - 34.5 inches
Denver, CO - 10.5 inches Conifer, CO - 27 inches
The snow will finally come to an end there by tomorrow morning and that same system will move across the Central Plains and into the Mississippi Valley region tonight. Ok, enough about Denver, I know you all want to know about our very own chances for snow closer to home.
There are a few things at play here that will bring the chance for snow into the D.C. area. The first is that area of low pressure and associated moisture currently over the Plains states. The other is oddly enough a disturbance over parts of Northern Canada that is expected to reach the Mid Atlantic region by Sunday morning. It will be the interaction of the two that ultimately determines the duration and amount of snow we recieve in the D.C. area.
The latest guidance depicts the chance for rain beginning in the evening hours on Saturday before changing over late Saturday night and early Sunday morning to light snow. It appears light snow would then be possible through the remainder of the day on Sunday with temperatures in the mid 30s by the afternoon. Let's take a look at one of the thermal profiles, this one being the forecast from the 12Z mm5 model.
- 925mb Temps, SLP and 10m Winds
Notice at 925mb how cold it is. 925mb is about 2500 feet. This is not at surface level but very important as you like to get an idea of how deep the layer of cold air is aloft. I have drawn a nice yellow line denoting the 32 degree line, showing the entire D.C. area below freezing at that level by 8am Sunday morning. This is interesting as precipitation appears likely at that time period and it should more than likely fall in the form of snow. That same model brings about a 50% chance for frozen precipitation at that time period. I'm thinking that is about right. The northeasterly winds will ensure cold air is being pushed into the region as the weak high spins over the northeast.
With precipitation possible through the late afternoon hours on Sunday, the chance for measurable snowfall appears likely. HPC places the region in an area of about a quarter to a half inch of precipitation. If this were all snow, that could mean up to 5 inches of snow for the region but since rain will mix in, we think there is more of an opportunity for a couple of sloppy inches. Remember this is still early in the game so changes will be likely, but these are our thoughts for now. Here's a nice idea from one of our models of how much snow COULD fall by Sunday evening.
- Our 18Z Microcast forecast snow accumulation