【Snow Squall Short-Term Forecast】Strong echoes rescue the dry zone operation

I believe many of you noticed this morning that the snowfall forecast seemed off? This is actually a limitation of weather models: they cannot properly identify the "false echoes" caused by dry areas near the ground.

Although the warm and moist cloud layer aloft has arrived (forming high-altitude echoes), the earlier dry and cold air mass has left a dry zone with relatively low humidity near the surface, which appears on radar as a "echo hole" around the radar station (Figure 1). Snow falling from aloft must pass the test of the dry zone to reach the ground, and must not be sublimated.

The only way for warm and moist air to break through the dry zone is continuous "moistening" by strong echoes, and this process has already partially succeeded: light snow is falling. According to current radar extrapolation, a stronger yellow echo around 12:30 PM will completely eliminate the dry zone over Thunder Bay, and the real heavy snow is about to arrive.