LaCrosse Tribune: National Weather Service radar captured a hatch of mayflies May 29 along the Mississippi River. Flowers bloomed in a month better known for showers. Sap stopped flowing in March, and mayflies hatched in May. It was the second-warmest meteorological spring on record for La Crosse and the driest since 1996, according to the National Weather Service. It also was the first spring without snow in 127 years of modern observation. “It’s been a very strange spring,” said Karl …