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SUNY (Syracuse): "Preliminary investigation of WSR-88D data for winter hydrometeorological events in upstate New York"

Final Report

Precipitation in the form of snow typically accounts for about 40% of the total annual precipitation in upstate New York watersheds. Accurate snow accumulation and snow water equivalent data are needed for short-term (1-3 day) hydropower scheduling decisions, intermediate term (3-5 day) flooding forecasts and longer term (seasonal) water resource management decisions. Realtime measurement of snow precipitation will also allow earlier forecast or warning of severe snowfall measurements.

The purpose of this project was to examine the performance of the WSR-88D Doppler radar for tracking regions of localized snowfall during the winter seasons of 1994-1995 and 1995-1996. A snow gauging network was established in the Heiberg Forest, Tully, NY, and hourly snow accumulation (S) and snow water equivalent (W) measurements were made for eight snowfall events. Concurrent WSR-88D reflectivity versus snow accumulation (Z-S) and snow water equivalent (Z-W) relationships are currently being developed for the data set. A preliminary finding is that such reflectivity-snow relationships differ as a function of storm (and hence snow) characteristics.

The quantitative examination of radar returns and snowfall/snow water equivalent rates has highlighted for the NWSO Binghamton forecasters the important role played by atmospheric thermal and moisture variables. As a result, forecasters have been able to anticipate how certain snowfall rates would be depicted on radar by evaluating model forecasts of the vertical temperature and moisture profile. Improved understanding of Z-S relationships has also helped the forecasters issue more detailed and more accurate short- term forecasts.