Added on: April 1, 2011
When flying under instrument flight rules (IFR), knowing the freezing level before you depart is paramount no matter what the calendar says. But it is especially important to monitor the freezing level closely during the spring and fall when it tends to change the most on a day to day basis. Also during this time of the year, it is quite common for there to be two or more altitudes where the temperature crosses the 0 degrees Celsius isotherm. This is more commonly referred to as multiple freezing levels. Multiple freezing levels are a common characteristic of freezing rain events that typically produce supercooled large drop (SLD) icing at the surface and aloft. In this workshop we will look at several forecast products to evaluate the presence of multiple freezing levels.