Central Northern/Central/Northeastern/East Central Squall Line of April 6th/7th 1921

The North Central, Central, and Northeastern Squall Line of April 6th/7th, 1921 was the 2nd of 4 highly dangerous squall lines occuring after The Demonic Summer of 1920 known as the 1921 Squall Line Series.

Meteorological History
At 4:21 PM, a weak squall line formed in the North Central World Province, and hit an area of convection, rapidly intensifying into what would today be a derecho at 5:00 PM. Over the course of 8 and a half hours, the line moved South through the North Central and Central provinces, clipping the East Central province. 3 tornados were spawned, 2 weak short lived F-1s and an F-3 that caused quite a bit of damage.

Daily Regional Forecast (NCWS)
Today, the Northwestern portion of the North Central Province is expected to see partly cloudy skies throughout the day. The Southwestern region is expected to see cloudy skies with occasional showers. The North, South, Northeast, and Southeast portions are expected to see thunderstorms today, with possible severe development in the Northeast and Southeast regions.

Daily Regional Forecast (CPWS)
It is expected to be cloudy in areas of the eastern portions of the province, with a chance of thunderstorms. Some of these storms may be strong or severe. The rest of the province is expected to see sunny weather, with southwestern areas expected to be partly cloudy.

Post Storm Report (NCWS)
A dangerous squall line pushed through the region yesterday. It originally started as a weak line of wind storms, and it is believed that it intensified after it hit an area of atmospheric convection. 2 F-1 tornadoes were spun up, but the vast majority of the damage was due to the wind. 7 people in this region died as a result of the system, and about 3 million people are without power just in this region, with more outages expected in the central region.

Post Storm Report (CPWS)
A powerful squall line came south into the region during the early morning hours of April 7th after spawning numerous reports of wind damage in the North Central province. This region was hit the hardest in the entire event, causing 6 million reported power outages, an F-3 tornado that decimated a small town, and the deaths of 9 people.

Post Storm Report (ECWS)
The extreme far western portions of the East Central Province were clipped by a dangerous squall line event during the early hours of April 7th. 2,789 people have lost power, but there is not much wind damage, and no deaths have been reported.

Derecho Reclassification (SWWS, 1961)
Along with 3 other squall lines that occured around the world, the squall line of April 6th/7th, 1921 has been reclassified under a new meteorological term, a derecho. The criteria for a derecho is as follows: the line of storms must last 6 hours or more and have sustained winds of 60 miles per hour throughout the event to be classified as a derecho.