|Slide 37 of 44|
Eta forecast sounding at BGM valid 10/25 17z.
The 5 hour forecast showed that the boundary layer would cool to just below freezing as the heaviest precipitation fell at BGM around 17z. As a result the Bourgoiun algorithm was forecasting snow at this time (indicated by the 4 blue dots). Note the deep layer that is near or just below freezing on the sounding. This is a classic signature for heavy, wet snow, as cooling due to melting results in cooling of a deep layer of the sounding to near freezing. Once the sounding cools to freezing, the melting stops, and the thermal profile remains near freezing.