Snow still looks likely for Sunday afternoon and Sunday night. Start and stop time, right now, appears to be around noon Sunday to shortly after sunrise Monday. This could adjust as we learn more about the atmospheric conditions…so stay updated on the forecast.
I wanted to take a moment to talk about why I think it will be a fluffy snow. Snow formation is dependent on moisture, temperature and how fast the air is rising. The hardest of those three things to forecast is where the air is rising the fastest. What is easier is the temperature profile in the atmosphere. Snowflakes fall in so many different shapes and those shapes typically happen at different temperatures. The snow flake that produces the most snow is a dendrite. It is a larger snowflake, so as they pile on top each other there is more air between them and the result is deeper snow.
The larger dendrite snowflakes form when the temperatures are between -12C and -18C. The chart below is a forecast sounding (a vertical profile of the atmosphere at a given point and at a given time). The area highlighted in yellow is the -12C to -18C area called the “Dendritic Growth Zone”. The red line is the temperature and the green line is the dewpoint. When they come close, like they are, it means the atmosphere is saturated…cloudy. Now when the atmosphere is saturated in that zone the chance of fluffy snow is good. And the deeper a saturated atmosphere falls in that zone the chance of fluffy snow increases. The depth, on the chart below, is considered very good for dendrites to grow. This is where were can get large snow ratios of 15:1 or 20:1. That means it does’t take a lot of moisture to produce accumulating snow.