Trainers of some Kentucky Derby (gr. I) horses were altering plans this past weekend, juggling work schedules to avoid the rain. If the National Weather Service is correct, no one should have to worry come Derby day.The forecast for Saturday is partly cloudy skies and a high of 77. That follows a Kentucky Oaks day Friday forecast to be partly cloudy with a high of 75. There is a slight chance of showers on Thursday.Last year, it was dreadful on Derby day, with a thunderstorm and heavy, blowing winds causing patrons to scurry for cover. Smarty Jones won the Derby on a track labeled sloppy.