The Effects of Lake Breezes On Weather (ELBOW) 2001 was a field study conducted by the Meteorological Research Branch (MRB) of the Meteorological Service of Canada in association with several Ontario Universities including York University. One of the goals of the project was to study lake breeze fronts to determine the role that such convergence lines play in generating severe weather. It also offered a unique opportunity to test the utility of the issuance of subjective Probabilistic Quantitative Precipitation Forecasts (PQPF) for several point locations within the field study domain over a large part of southwestern Ontario. The ELBOW 1997 field study (King and Sills, 1998) and other works identified that many excessive rainfall producing quasistationary Mesoscale Convective Systems (MCS) in southwestern Ontario are largely governed by the development and propagation effects of lake breeze boundaries. Previous research has also demonstrated the value and merit of PQPF as valuable guidance for flood forecasting and risk management in small to medium sized watersheds (Krzysztofowicz, 1998).

The experimental PQPF products for ELBOW 2001 are described as well as the preliminary verification results. It is hoped that the knowledge gained from this real-time experiment will be valuable to future endeavors in PQPF. Several of these findings are also presented.