Correlation of Radar Reflectivity and Snowfall Rate during Moderate to Heavy Snow

Radar reflectivity in falling snow varies slightly with prevailing types of snow crystals. Experimental results in major New England snowstorms indicate that the most significant difference in determining the rate of snowfall by radar reflectivity occurs between wet and dry snow. In dry snow surface temperature below freezing, the correlation coefficient between radar returns and snowfall rate runs as high as r 0.85. However, in wet snow surface temperature above freezing with bright band characteristics, the correlation coefficient is very poor, as low as r 0.35. In spite of this anticipated problem, radar is a reliable means of determining dry snowfall rates and provides a potential technique for snowfall forecast improvement. Author