A strong winter storm, nicknamed Winter Storm Nyla by The Weather Channel, produced significant impacts across the United States. Notably, a strong blizzard occurred over the High Plains and Midwest, where winter weather and blizzard warnings were issued. Thunderstorm development created the risk for severe weather and tornadoes, especially in northern Illinois and Indiana, spawning 15 tornadoes on March 19.
On March 17, the NWS forecasted that a relatively strong upper-level trough would move into California by the afternoon, with updrafts strong enough and instability high enough to produce lightning and small hail. That day, lightning, snow, and hail up to an inch in diameter were reported across northern California. The trough passed through California and the Great Basin area throughout the afternoon of the 18th, placing the system over the Midwest by the late evening. Moisture was present in the air, but due to limited atmospheric instability, the primary threat would be potentially severe hail centered over Iowa in the overnight and morning hours. On the morning of the 19th, large amounts of up to quarter-sized hail fell across parts of Iowa. Additionally, large amounts of snow fell in a relatively narrow band stretching from Kansas to Wisconsin. Coupled with high winds, whiteout conditions were created in some of these areas. Thundersnow was reported in these areas.
By the afternoon of the 19th, atmospheric destabilization occurred ahead of a cold front and dry line, allowing for widespread thunderstorm development over central Illinois. High winds brought by the system allowed for supercell development, although their strength was limited due to relatively low instability and moisture in the air following a larger outbreak days earlier. However, the environment remained volatile and tornadoes, potentially strong, remained a possibility throughout the afternoon. 15 tornadoes were confirmed, including three that passed through Gary, Indiana and one EF2 tornado, the strongest of the outbreak. The strongest of the Gary tornadoes, rated EF1, caused an injury when a roof collapsed on a woman.
An intense dirty rain event was caused by the system; dust, as well as wildfire smoke, was lofted into the atmosphere by the system, which fell as rain over a large region. Dirty rain was reported in Chicago, Illinois, Des Moines, Iowa, Nashville, Tennessee, and Toledo, Ohio.
Blizzard conditions and downed power lines from strong winds forced parts Interstate 70 and Interstate 80 to shut down. Dust transported from northern Mexico and Texas caused poor air quality as far away as Iowa. Over 250,000 people across the country have been left without power due to the storm.
At least 38 wildfires have broken out across Arkansas, causing the obstruction or closure of many roads.
Three tornadoes struck Gary, Indiana on March 19. Damage was sustained to the McCullough Academy, a public school, as a tornado sheared its roof and damaged several classrooms and the gymnasium. Another tornado injured a woman after her roof collapsed. A shelter was established at the Monroe Center for those displaced by the tornadoes.