Enroute Icing

### Produced by The COMET® Program

### Step 1: Diagnosing Locations of Icing » NWP Analyses » Model Soundings - Data

#### Question

Here’s the RUC2 analysis sounding for the nearest grid column to Davenport IA (DVN). Using the same criteria you’d use for Skew-Ts, enclose the area with a risk of icing.

Use the pen to enclose the area with a risk of icing.

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An atmospheric layer from about 700 hPa to the surface is near saturation, with temperatures around -10°C. The sounding looks almost identical to the radiosonde from DVN taken at the same time. It lends more confidence to the NWP analysis near DVN and the model forecast for later forecast hours. Forecasters using BUFKIT software to plot RUC or NAM soundings can overlay vertical motion (Omega). This allows quick identification of upward vertical motion (negative Omega values) in moist layers, which correlates to higher icing potential and severity.