Ana pays a visit
April showers, the cruelest month, or the tax man cometh all speak to the volatile nature of April weather. We are watching this first hand with delightful weather on the weekend bringing temperatures near 80 degrees. Warm southerly winds brought the warm temperatures. Much colder air is advancing from the west, however, and a surprise is in the forecast for snow in the Adirondacks.
We use the term cold front to describe this rapid shift and the name describes it well. They are frequent visitors but this particular type of front is more common during the spring months when there are significantly different air masses colliding. It is described as an ANA front because the wind shift occurs before the new air mass arrives. Imagine a conveyor belt transporting warm air to our region form the Gulf of Mexico. To our west, the cold air is pushing toward the Atlantic and because cold air is heavier it forces the warm air up into the sky where it cools off and the moisture condenses, resulting in rain.
Frequently the show is over as soon as the temperature changes on the ground and the cold air arrives but with ANA, there is enough moisture still available to allow the rain to continue. Rather than dry air following the front the rains will continue — if it becomes cold enough it will turn to snow. As in any weather related event, this is a model and circumstances can change the picture but it will be interesting to watch the wind vane and the thermometer during the day. Be prepared for the winter wear in the morning!