Rare Level 4 out of 5 threat issued ahead of major severe weather outbreak stretching 1,000 miles on Monday

Parts of Kansas stretching up into Nebraska face a rare level 4/5 severe storm threat as the atmosphere will be primed for violent storms producing tornadoes and huge hail.

Millions of Americans across 1,000 miles of the Plains and Upper-Midwest are bracing for an extremely dangerous severe weather outbreak on Monday, just hours after strong storms slammed the region on Sunday.

Starting Monday, parts of central and northeastern Kansas stretching up into southeastern Nebraska are under a rare level 4/5 severe storm threat as the atmosphere will be primed for violent storms producing tornadoes and huge hail. 

Monday's setup comes as a strong upper-level storm system moving out of the Southwest U.S. will collide with a surge of hot and humid air across the middle of the country.

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A highly volatile atmospheric powder keg will ignite, unleashing a severe weather outbreak including intense tornadoes just hours after Sunday's storms slammed the same region. 

Central Kansas, stretching through southeastern Nebraska, southwestern Iowa, and Northwestern Missouri, will be the primary threat zone for the strongest storms on Monday, as warm, humid temperatures fuel these conditions.

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By Monday afternoon, an atmospheric "lid" is expected to trigger explosive thunderstorm development along a cold front and dryline, according to the FOX Forecast Center. 

The initial storms will quickly intensify into rotating supercells in a primed environment that could be the perfect set of conditions to produce violent, long-track tornadoes.

As a result of the severe weather, large hail ranging from baseball to softball-sized is possible due to these supercells.

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The intense conditions are expected to persist into the overnight hours on Monday as a wall of heavy rain and strong winds that will impact at least a dozen states. 

Severe weather threat pushes into Tuesday

As storms continue into Tuesday, severe storms will expand into the Ohio Valley, where a level 2/5 severe storm threat has been issued. 

Tuesday's storms will pack widespread 1–2 inches of rain from Northern Minnesota through northeast Texas, where a minor risk of flash flooding is possible as well as these storms push east. 

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The multi-day severe weather threat wraps up by the end of Tuesday, before the wet weather returns for millions of Americans headed into Memorial Day weekend.