Severe thunderstorm outbreak with hurricane-force wind gusts underway in Eastern US

A severe weather outbreak is underway on Monday as thunderstorms unleashed damaging wind gusts, hail, drenching rainfall and even a few tornadoes.

Live updates: Damaging storms racing across Eastern US

Accounting for every level of severe storm risk, around 120 million people in the Eastern US could be impacted by damaging weather Monday and Monday night as a potent storm system, especially for August, crosses the region.

Wind gusts in the strongest storms could reach speeds of 60 to 80 mph. The upper end of this range is equivalent to hurricane-force wind gusts and can cause significant damage.

Power outages and flight cancellations mounted as storms slammed several states with strong winds.

More than 170,000 customers were without power on Monday afternoon across the East, with the majority of outages in Tennessee, Georgia and West Virginia, according to PowerOutage.us.

Over 1,000 flights were canceled Monday with 4,500 additional delays as storms disrupted flight paths to major hubs like Atlanta, according to data from FlightAware.

A Level 4 of 5, moderate risk of severe thunderstorms is in place Monday - the first Level 4 issued in the US since June 29 and the first for Washington D.C., in over a decade. People who live or work in the area should have a plan in place to take shelter if warnings are issued.

The greatest risk of widespread, potentially destructive winds will center along a more confined corridor from western Virginia to far southern Pennsylvania as storms roar to life Monday afternoon. Home to more than 13 million people, the corridor includes major population centers like Washington, D.C., and Baltimore.

Damaging winds will also be the most prevalent impact anywhere from Alabama and Georgia northward into New York and New Jersey. Some major cities at risk include Atlanta and Philadelphia.

Robust winds may damage property, snap tree branches and bring down power lines which could leave some residents without power or air conditioning after high temperatures reach into the 80s and 90s in the East Monday afternoon.

A few tornadoes are also possible from portions of the Southeast to the Northeast. Several tornado watches were issued by Monday afternoon, covering around 40 million people across a large area from western Tennessee and Kentucky eastward into portions of North Carolina, Virginia, Maryland, Pennsylvania, New Jersey and New York. The greatest risk of tornadoes on Monday will stretch from eastern Kentucky into central Maryland.

Tornadoes may spin up quickly in the same lines of storms bringing damaging winds, giving little time to get to safety.

Heavy downpours can accompany any storm, but the greatest risk for rainfall leading to flash flooding will be in place across the mid-Atlantic and Northeast. Flash flooding can quickly turn safe roadways into raging rivers.

While parts of the East brace for hail and heavy rain, cities from Arizona to Florida will continue to deal with dangerous heat this week.

"Numerous record high temperatures and record high morning minimum temperatures are likely over the next few days with no end in sight going into the later part of this week," the National Weather Service said.

Excessive heat warnings and heat advisories in effect across the southern part of the country, from southeast California into Florida, will likely remain in effect "for the foreseeable future as there is no relief in sight to the heat for the remainder of the week across these areas," the weather service said.

About 65 records were set or tied over the weekend across cities in Arizona, Louisiana, Mississippi, New Mexico and Texas. Dozens more could be set through Tuesday.

Austin, Texas, hit 105 degrees Sunday, marking the 30th consecutive day with a high temperature over 100 degrees.

Albuquerque reached a high of 102 Saturday - breaking the prior record of 98 degrees set in 1995. This is also the hottest August day ever in the city.

In New Orleans - where city officials warned that high humidity levels will result in high heat index temperatures of 115 degrees or higher - cooling centers were open for residents in need of respite from the heat, officials said.

"The forecasted excessive heat warning for Monday, Aug. 7 will mark the 17th excessive heat warning issued for 2023 so far, beating the previous record of five warnings in 2021," New Orleans officials said in a news release.

CNN Meteorologist Gene Norman and CNN's Raja Razek contributed to this report.