GOOD MORNING, Prices are lower as more organized rainfall hits key growing areas across Minnesota, Illinois, Missouri, and Iowa.   Heavy showers pushed through the St. Louis area yesterday, dropping temperatures by 20 degrees.  Today, the extreme heat is back.  With the late plantings, the peak pollination period for corn appears to fall from July 20th to August 10th, much later than the usual July 4th period.   Weather maps are not in full agreement as to extended forecasts, but this week will continue to feature some of the hottest temperatures of the year.   Grains are leading in terms of weakness with longs liquidating part of their overall position.   ANNOUNCEMENTS It was reported...