A severe weather threat looms across the south-central U.S. on Monday, with 40 million people under flood watches due to potentially heavy rainfall.

ABC News’ chief meteorologist Ginger Zee is tracking the rain as millions brace for more severe weather and a flash flood threat.

Heavy rains were continuing to lash Puerto Rico and flash flood warnings persisted across the U.S. territory, submerging streets, stranding families and causing at least one death

Damaging wind gusts, large hail and the potential for tornadoes are all possible throughout Sunday and into Monday.

Damaging winds, large hail, and isolated tornadoes are possible.

More than 25 million people are under threat of damaging winds and possible tornadoes.

At least seven people have died in Oklahoma amid heavy rain and dangerous flooding. Sarah Greeley, who was at the vet when the weather started to pick up, joins ABC News to share her story.

At least one person was injured and five homes were damaged after a tornado ripped through Texas Hill Country and two people died during dangerous flash flooding in Oklahoma.

For the fourth night, dangerous storms with record-breaking, deadly flooding are slamming the Midwest.

Severe weather and flash flooding continue to threaten much of the central and eastern U.S. on Thursday, disrupting Americans' travel plans.

Americans from Texas to the Ohio Valley are on alert for possible tornadoes, hail and flash flooding as the severe weather leaves hundreds of thousands without power and causes chaos for air travel.

Four people died during storms in Pennsylvania on Tuesday night, authorities said.

The U.K. is set for its hottest day of the year so far, and forecasters say temperatures could hit 30 degrees Celsius (86 degrees Fahrenheit) at the earliest recorded point in the calendar

The damaging storm system stretching from Texas to New York has left more than 500,000 without power and has killed at least four people.

ABC News’ Ginger Zee has the latest on the damage after vicious storms caused reports of flash flooding, hail and winds up to 90 miles per hour.

Powerful storms are barreling across hundreds of miles from Texas to western New York, with wind gusts up to 90 mph and tornadoes shearing through buildings in some regions.

Forty-five million people from Texas to New York are on alert for severe weather on Tuesday.

More than 36 million Americans are on alert for severe weather in the Midwest, with thunderstorms, large hail and a tornado outbreak possible on Monday.

ABC News’ Ginger Zee tracks the latest path and timing of the severe weather as tornadoes, hail and thunderstorms threaten millions across the Midwest.

More than 50 million Americans are on alert for severe weather.

Tornadoes have already caused significant damage in Texas, and flash floods have turned deadly in Oklahoma, as severe weather slams parts of the United States.

More than 30 million Americans on alert for severe weather over Easter weekend.

A storm system centered over the central United States continues to bring a multi-day stretch of severe weather across parts of the Plains and Midwest.

Meteorologist Greg Dutra from ABC News' WLS station reports on the slow-moving storm system from Texas to the heartland of America.

More than 30 million people are on alert for multiple rounds of severe storms that are slamming parts of the plains and Midwest, including tornadoes, large hail and damaging winds.

More than 50 million residents are on alert for severe weather heading into the holiday Easter weekend.

More than 6 million people in multiple states across the Southwest and South Plains are under red flag warnings on Thursday.

ABC News’ Sam Champion has the latest on the fire threat in parts of the Southwest and Southern Plains.

Snow and rain persist in the Northeast as summer temperatures move into the West

The extreme flooding across parts of the South and Midwest was caused by a stalled storm system that hovered over the same area for long periods of time.

Flood alerts remain in effect in the wake of days of deadly storms that devastated the central U.S. with catastrophic rainfall and destructive tornadoes.

Significant severe weather and life-threatening flash flooding continue to impact much of the mid-South up through the Ohio River Valley.

The mother of a 9-year-old boy is speaking out after he was swept away and killed by floodwaters in Kentucky.

ABC News’ Alex Perez reports on the widespread flooding in the wake of deadly storms that have devastated the South and Midwest.

ABC News’ Ginger Zee is tracking the latest on the flooding after deadly severe weather swept across multiple states over the last several days.

The same system that spawned over 150 reported tornadoes brought one final punch of rain and thunderstorms to the Southeast, and a cold blast from the Midwest to the Northeast triggered freeze alerts.

At least 20 people have died since last Wednesday, as catastrophic flooding and severe storms swept across multiple states.

ABC News’ Ginger Zee has more as the storm moves toward the Southeast and has the latest on the spring cold blast on the way for millions.

ABC's Morgan Norwood reported on a once-in-a-generation storm that moved across the United States in the past week, killing at least 18 people.

More than a foot of rain has fallen in some areas as a series of powerful and deadly storms move through the South.

Relentless storms hit the South for a fourth straight day leaving more than 50 million people on alert. In Arkansas, three months of rain fell in three days.

​​A four-day, once-in-a-generation weather event is pounding the middle of the U.S. with destructive tornadoes and life-threatening flooding.

Texas in the bullseye for tornadoes overnight amid dangerous flash flooding across parts of the south.

The massive storm system that's spawned tornadoes and flooding is threatening millions from Kentucky to Texas.

ABC News’ Ginger Zee tracks the latest storm path and what’s ahead for the battered region.

The same states in the Midwest and South that were slammed by deadly tornadoes braced for round two as a once-in-a-generation weather event strikes again.

Amid a multi-day event, millions are facing a severe weather outbreak and flooding rain from Texas to West Virginia.

Multiple tornadoes reported across the South and Midwest have caused “catastrophic” damage.

A once-in-a generation extreme weather event is beginning Wednesday with a tornado outbreak and will continue into the weekend with dangerous, life-threatening flooding.

At least 32 million Americans from Arkansas to Ohio are under flash flood threats. Strong tornadoes, large hail and damaging winds are also possible from Little Rock into southern Indiana.