Megastorm may bring blizzards, tornadoes, flooding and even fires across much of US: Where, when it will hit

More than 100 million people in the U.S. will be in the path of an intense March storm starting Friday as the sprawling multi-day system threatens fires, blizzards, tornadoes, and flooding as it tracks eastward across the Great Plains.

Scientists said the storm's strength and potential for far-reaching impacts is notable, but its timing isn't particularly unusual. Extreme weather can pop up in spring because storms feed on big temperature differences between the warmth that’s starting to show up and the lingering chill of winter.

“If there’s a time of the year where a storm like this can deliver these coast-to-coast impacts, we are in it," said Benjamin Reppert, meteorologist at Penn State University.

The National Weather Service forecast strong winds stretching Friday from the Canadian border to the Rio Grande, with gusts up to 80 mph, which creates a significant fire risk in Texas, New Mexico, and Oklahoma. Meanwhile, a winter blast was expected farther north in parts of the Rockies and Northern Plains, with possible blizzard conditions in the Dakotas and Minnesota.

The central region from the Gulf Coast to Wisconsin is at risk of severe thunderstorms that could spawn tornadoes and hail. On Saturday, severe storms are forecast to move toward Louisiana, Mississippi, Alabama, Tennessee and then into Florida. Potential flooding was a concern from the Central Gulf Coast through the upper Ohio Valley.

The turbulent weather is expected to arrive on the East Coast Sunday with strong winds and a flash flooding risk in localized areas. Heavy rain was forecast along the Interstate 95 corridor south to Jacksonville, Florida.

Reppert noted that temperatures in the upper atmosphere in much of the central and eastern U.S. are close to record levels for this time of year, while a cool air mass behind the storm in the western states is one of the coolest on record for that region and this time of year. He said that combination could be behind part of this storm’s expected strength.

Russ Schumacher, a climatologist at Colorado State University, said the storm could become a bomb cyclone Friday afternoon or evening — a designation given when a storm intensifies so rapidly that atmospheric pressure drops a certain amount in a 24-hour period. That would mean higher winds and more intense rainfall.

In addition to fuel from big temperature swings, the storm will be shaped by the jet stream. In a fairly typical position for this time of year, it's diving south across the U.S. and will help lift air and moisture into the atmosphere to fall back as rain.

The storm also will tap into heat and moisture from the Gulf of Mexico, also referred to as the Gulf of America as declared by President Donald Trump, which is 2 to 4 degrees Fahrenheit (1.1 to 2.2 degrees Celsius) warmer than historic averages.

“You kind of have this Goldilocks situation,” said Ryan Torn, professor of atmospheric and environmental sciences at the University at Albany, referring to the mix of ingredients in the atmosphere that will add to the storm’s strength.