Millions of Americans face Memorial-holiday travel chaos as forecasters warn to brace of yet another spate of storms.
Towns devastated by weeks of torrential rain, thunder, and powerful tornadoes are back in the firing line this week.
National weather warnings are in force through the start of the week as volatile weather conditions plough the country.
Some 44 million hitting the roads on Memorial Day, according to the American Automobile Association (AAA), are urged to check forecasts and take extra care.
Weather Channel meteorologist Chris Dolce said: “The weather may have a say in people’s Memorial Day holiday plans.
“There will be significant threat of severe storms from the mid-Mississippi, Ohio and Tennessee valleys.
“The risk of thunderstorms may extend into parts of the Great Lakes, Appalachians, and a few spotty storms can't be ruled out in the mid-Atlantic and Southeast.”
The National Weather Service (NOAA) has ‘tornado watch’ warnings in force in Missouri, Illinois, Arkansas and Tennessee.
Separate severe weather advisories are in place across Michigan, with flood alerts in force in across central-eastern states, Iowa, Minnesota, Dakota, Montana and Wyoming.
A NOAA ‘special weather statement’ has been released for strong thunderstorms and hail in New England, New York, Maine and the north east.
A spokesman said: “The chance of severe weather and heavy rain shifts into the Mid-Mississippi, Ohio and Tennessee valleys before progressing into the Mid-Atlantic, Southeast, and Gulf Coast on Memorial Day.
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“Damaging wind gusts, large hail, and tornadoes are possible while heavy rain may lead to scattered instances of flash flooding with this initial burst of thunderstorms.”
The storm centre will move over the Great Lakes later on Monday pulling the risk of severe weather across southern and eastern states, he said.
He added: “Damaging wind gusts and hail are the primary potential hazards.
“Residents and visitors planning to enjoy outdoor holiday barbecues and parties should remain weather aware and have multiple ways to receive warnings.”
A ‘huge’ low-pressure system moving across the United States will prolong a bout of storm misery which has gripped the US for weeks.
In the wake of a killer tornado which struck Iowa last week, twisters churning out giant hailstones will bulldoze central states through the start of this week.
A collision of hot weather to the south and cooler air to the north will drive the assault, experts warn.
Jim Dale, meteorologist for British Weather Services and US correspondent, said: “There is a huge area of low pressure that is moving over the Great Lakes this weekend.
“This will be powered by hot air to the south clashing with cooler air to the north, and on its southern flank, there will be a growing risk of thunder, tornadoes and big hailstorms.
“This is looking like another severe storm, similar to last week.”
AccuWeather chief on-air meteorologist Bernie Rayno added: “We can’t seem to get rid of this severe weather; it has been relentless over the past month.
“We are entering a very stormy period that coincides with the first unofficial weekend of summer.”