There are times when I ignore the forecast altogether. If the predicted weather is not matching what is actually happening, alarm bells should go off and you should go back to fundamentals. If the legs are short, the dominant factor is likely to be fleet positioning and geographic effects, not something you can divine from the forecast. Even on racecourses with longer legs, strategic or local effects can often override the forecast. For example, the forecast calls for a slow right-hand shift through the day, say 15 degrees over 5 hours. However, the left side is always better because there is a shoreline bending the wind. This effect is stronger than the slow righty, so you want to go left, even though the forecast would suggest right!