A recent study at McGill University provides new insights into how winter storms develop in the St. Lawrence River Valley, findings that could potentially improve the accuracy of winter weather forecasts in the region.
"These findings are essential because even small temperature shifts, as little as one degree, can drastically change the type of precipitation, turning rain into freezing rain or snow," said Juliann Wray, lead author and PhD student in the Department of Atmospheric and Oceanic Sciences.
"This has huge implications for public safety, especially during winter storms."
The study makes use of data collected for the WINTRE-MIX (Winter Precipitation Type Research Multi-scale Experiment) field program in 2022 at stations across northern Vermont and Southern Quebec, including at the state-of-the-art Earth Observing System lab at McGill's Gault Nature Reserve.
The research focused on identifying key features of weather fronts in the St. Lawrence River Valley and understanding how they influence precipitation types and amounts.
Researchers observed that the region's unique terrain contributed to an increase in local precipitation.
Detailed data showed key differences in temperature at different heights in the atmosphere, which led to mixed precipitation events, such as freezing rain, snow, and rain, conditions that current weather models struggle to predict accurately.
The WINTRE-MIX program used a wide range of tools, including aircraft, upper air and remote-sensing instrumentation and surface weather stations, to gather high-resolution data during significant winter weather events. This comprehensive approach yielded a deeper understanding of how these complex weather systems form and behave.
About the study
Frontal Processes in the Saint Lawrence River Valley During the WINTRE-MIX Field Program was Juliann Wray's master's thesis, completed in August 2023, under the supervision of Professor John Gyakum.
