Vertical profile of the atmosphere.. rain vs. snow

Here on the Cape it is a different weather world. Our winds blow off the water, and poof! what should have been snow, sometimes is rain. Even in the great Blizzard of 78' we managed in some parts to escape, and yet last winter we had nearly 100" of snow. What about this weekend. Well, one tool to use is called a "sounding" or vertical profile of the atmosphere. When look at it, you can see warm layers of air that may intrude. Here on the Cape though, it is the lowest layer that is usually indicative of the warm marine air. Let's see what it is "supposed" to look like during the storm this weekend. I used Chatham to try to get the warmest possible reading from the storm. If you CLICK ON the chart you will see that only the very lowest layer of the atmosphere, (you are looking at the atmosphere top to bottom on this chart, the red line is temperature) is above freezing. That means that if it snows hard enough, it should wipe out the warmth and bring us a wet snow. However, often when storms move closer than expected this changes and we become too warm anyway. This is a real toss-up at this point for the outer cape... as we are sure it is cold enough "aloft" for snow, the only wild card is right near the surface itself. To find out how to read soundings and weather maps off the links on this page, purchase WEATHERMAPS, 3rd edition by Peter Chaston available here.