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EZTip No. 19 - Icing forecasts on the EZRoute Profile with an inversion present

There will be times in the EZWxBrief progressive web app where you may see icing probability (and severity) depicted below the freezing level in the EZRoute Profile or Meteogram. That usually means there's a temperature inversion present near the surface. Notice below on this route from the Cumberland Municipal Airport (KUBE) in Cumberland, Wisconsin to Charles B. Wheeler Downtown Airport (KMKC) in Kansas City, Missouri that the freezing level (0°C isotherm) varies from the surface near KUBE (on the left) to nearly 10,000 feet MSL at the destination (on the right). Most of the middle part of the route, however, the freezing level is shown to be around 5,000 feet MSL. But you likely also notice that there's icing probability depicted immediately below the freezing level through most of the latter part of the route. What's going on?

First, this is a clear indication that multiple freezing levels exist. The EZWxBrief app only shows the highest freezing level in most cases. For example, looking approximately 100 nm along this route, the 2-hour forecast sounding from the Austin Municipal Airport (KAUM) in Austin, Minnesota clearly shows two freezing levels with the highest freezing level near 5,000 feet MSL that is shown in the EZRoute Profile view above.