A historic tornado onslaught in central U.S.

The U.S. has been hammered by an onslaught of severe weather, as a persistent weather pattern set up a clash of seasons across the central U.S.

The state of play: Epic flooding has also been affecting the Upper Midwest, Plains, central U.S. and Mississippi River Valley this spring, with many locations seeing their highest water levels on record.

• Parts of Oklahoma have picked up more than 400% of their typical May rainfall.
• As of May 29, the Mississippi River in the St. Louis area has been at or above flood levels for over 70 days, according to the National Weather Service.

By the numbers: Meteorologist Sam Lillo broke down some of the tornado statistics on Twitter. During the past 30 days, the U.S. has seen:

• 584 tornado reports.
• 13 straight days with 8 or more tornado reports.
• 10 straight days with 16 or more tornado reports.
• Only 3 days without tornado reports.
• 185 severe weather watches issued by the Storm Prediction Center.

Context: While the heavy rains are consistent with studies showing an increase in heavy precipitation events and stalled, highly amplified weather patterns due to climate change, trends are tougher to discern with tornadoes.

Studies suggest that environments supporting severe weather will increase but become more variable in coming years, leading to potentially bigger tornado outbreaks that are fewer in number. They also project an eastward shift in "Tornado Alley" as the climate warms and storm environment changes.

Go deeper:

• The states where the most tornadoes hit
• The deadliest tornadoes in U.S. history