April 7th-9th, 2020 Tornado Outbreak

The tornado outbreak of April 7th and April 8th, 2020 was a historic event that set new records. The outbreak impacted the states of Iowa, Missouri, Arkansas, Wisconsin, Illinois, Indiana, Michigan, Ohio, Kentucky, Tennessee, and Pennsylvania; and was the worst outbreak of the Hoosier Alley since 2013. In all, it marked the beginning of a violent future for tornadoes.

Meteorological Synopsis
During the late morning hours of April 7th, 2020, a strong lower level trough hovered over the Midwestern states, forcing an impressively deep surface low into Missouri. This deep low combined with a notably strong jet stream set up significant instability in the atmosphere, creating a deadly mix of conditions that would produce multiple violent tornadoes across the Midwest for the next two days.

On April 1st, the Storm Prediction Center had issued a 15% severe weather risk area stretching from western Illinois to eastern Indiana on days 6 and 7 of the SPC Convective Weather Outlook. On the approach of April 3rd, the Storm Prediction Center issued a 30% severe weather risk area stretching from central Illinois to a small portion of western Indiana, while expanding the 15% severe weather risk area from Missouri to Ohio. As of April 6th, outlook day 2 showed a high risk over eastern Missouri and outlook day 3 showed a moderate risk stretching from far eastern Illinois to Ohio. On the approach of April 7th, outlook days 1 and 2 showed back-to-back high risks stretching from central Illinois to eastern Ohio with CAPE ranging from 4000J/kg-5000J/kg, a worst case scenario.

April 7th -
Over the early morning hours, a moist, rainy air mass tracked a deep surface low over the states of Montana and Wyoming. As the clock struck noon, the air mass swung down into Nebraska, Kansas, and Oklahoma, and storms were already firing. As the storm system crossed into Missouri, supercells began dropping tornadoes across Arkansas, Missouri, and Iowa. By 4:00PM, more supercells erupted and tornado activity brought in storm chasers and media coverage from all over the country.

April 8th -
At about 11:00AM, supercells began flaring up east of Columbia up and down the state of Missouri, blasting east-northeast at 70MPH and producing 6 tornadoes. At around noon, the supercells crossed the Missouri/Illinois border, dropping 7 more tornadoes before reaching central Illinois, where activity picked up immensely.