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Weekly Weather Event -Week of April 6

April 10, 2020

Thursday April 9th into April 10th brought spring snows to many parts of the northern United States. Portions of New England received 6-12 inches of snow, totals which are more common in January than early April. The Upper Midwest, including Madison, saw rapidly changing weather patterns over the course of the day. Scattered snow and rain showers moved through southern portions of the state, and winds peaked at 52 miles per hours at Milwaukee- General Mitchell Airport. Over the course of the day, snow and graupel accumulated on the ground for a couple of minutes, melted as the sun came out, and repeated.

Sometimes called snow pellets or soft hail, graupel resembles small clusters of snow or easily breakable hail stones. This lesser-known type of frozen precipitation is formed when a snow crystal falls through a layer of water droplets with a temperature below freezing. These supercooled water droplets easily freeze to the falling snow crystal, building up a layer of ice around the snow crystal in a process called riming. Graupel typically remains under .2 inches (5 millimeters) in size, though it can grow to the size of a quarter coin under the right conditions.

Thursday and Friday’s snow showers are a precursor to the rest of Easter weekend, expecting to bring colder than usual temperatures to the northern Rockies, Great Plains, and Midwest. The cold weather is also expected to bring snow with some portions of Wisconsin expecting up to 6 inches of snow by Monday.