© KMOVTornado damage in Perryville, Mo.
The reclassification is an upgrade from preliminary estimates that the tornado was an EF-3, according to an update Saturday from the weather service.
The Joplin, Mo., tornado in May 2011 that killed 161 people and injured more than 1,000 was an EF-5, with winds estimated at more than 200 mph.
In Tuesday's tornado, wind bursts reached 180 mph. The tornado was six-tenths of a mile wide and traveled 50.4 miles, the longest track of a tornado in the weather service's Paducah, Ky., coverage area in 25 years.
The coverage area includes parts of southeast Missouri, Southern Illinois, western Kentucky and southwestern Indiana.
The tornado started about 5 miles northwest of Perryville and ended about 2 miles southwest of Christopher, Ill.
The weather service said there were signs of multiple vortexes near the easternmost part of Perry County near the Mississippi River, where the tornado reached its greatest width.
Travis M. Koenig, 24, of Perryville, was killed when the tornado tossed his truck 100 yards from I-55. Twelve people were injured in that area.
At least 100 homes had moderate to major damage, many more were leveled and the National Weather Service said thousands of trees were uprooted.
Meanwhile, Perryville police said Friday night that the city will not accept any more donations of physical goods, other than pet items through a local pet store and animal rescue group. Those volunteers can be reached at 573-517-8027.
"Due to the generous donations that have poured into our community since the Tuesday evening tornado and associated storms, we have determined that all physical needs have been met," the department said in a news release.
Comment: Not only was the twister the longest-track tornado in the region since 1981 - spending an incredible one hour and 2 minutes on the ground - but its parent supercell thunderstorm also followed a similar path to that of the 1925 Tri-State tornado (the deadliest tornado in U.S. history) according to the NWS.