Basic Offshore Weather with Les Chesneau

Saturday morning will consist of a weather primer. It will introduce mariners to weather basics including definitions, different layers of the atmosphere, how the atmosphere is heated, cloud formation and identification, and the concepts of pressure which provides a foundation for reading weather maps and 500 Mb upper air charts. This primer will provide knowledge of weather fundamentals enabling mariners to become self-reliant in their own weather forecasting.

Saturday afternoon will focus on understanding weather surface maps. We will start with the all important discussion of the marine advisory and warning system. We will then look at the scales of weather systems and how each affects the cruising sailor. A significant amount of time will be spent discussing synoptic scale weather systems and their associated fronts. There will be discussion on non-frontal troughs, ridges and squall lines. We will then discuss how to read and interpret surface pressure weather maps and how to avoid the heaviest weather. Lee will talk about understanding how forecasts are documented and the challenges of comparing 48 – 96 hour surface pressure forecasts. There will be a short discussion on receiving weather information at sea, followed by Questions and Answers.

Sunday all day will be spent putting this theory to practice. Students will use weather maps and other information to prepare weather forecasts and make strategic decisions. This day of forecasting practice under Lee’s guidance is perhaps the most valuable aspect of this weekend course.