Weather lore also choppy and unpleasant. Seagulls huddled on the ground may be a sign that the weather is already bad. Cows prefer not to have the wind blowing in their faces, and so typically stand with their backs to the wind. Since westerly winds typically mean arriving or continuing fair weather and easterly winds usually indicate arriving or continuing unsettled weather, a cowvane is as good a way as any of knowing what the weather will be up to for the next few hours. While it is true that cats and dogs eat grass, it has nothing to do with the
Weather window than 72 hours can be defined as weather-limited operations. These operations can be planned independently of statistical data and based only on weather forecasts. For weather-limited operations, critical factors such as forces, movements and acceleration shall be calculated in a rather worse weather condition (design criterion) than the weather in which it is planned to perform the operation (operational criterion). This is due to the unreliability of weather forecasts. The longer the planned operation lasts, the greater the difference between the operational criterion and the design criterion. The relationship between the operational criterion and the design criterion is defined as