An intense heat wave is set to blanket the eastern half of the United States, with dangerously high temperatures expected to persist for an extended period. Beginning late this week and peaking next week, this heat wave has the potential to break records and pose a significant risk to vulnerable individuals.

The heat wave will first impact the southern Plains, South, and Midwest, with widespread highs in the mid-90s to around 100 degrees Fahrenheit, surpassing normal temperatures by 10 to 20 degrees. By Monday, the scorching temperatures will spread to the Ohio Valley before making their way to the Mid-Atlantic and Northeast shortly thereafter.

Weather forecasters attribute the source of this oppressive heat to a sprawling heat dome centered over northern Mexico and the southwest United States. This heat dome, characterized by a strong zone of high pressure, is currently causing record-breaking high temperatures in some areas and is expected to shift eastward over the weekend. By next week, it will move toward the Mid-Atlantic, intensifying and expanding in all directions.

Some weather models even predict that this heat dome could attain historic strength for this time of year. The European weather model simulation indicates that its intensity may surpass the heat dome of June 29, 2012, during which Washington experienced a scorching June record of 104 degrees Fahrenheit. Similarly, Nashville recorded 109 degrees and Raleigh, N.C., reached 105 degrees on that same day.

While the eastern region of the country has already experienced one of the warmest years on record due to a mild winter and spring, the most extreme heat has been concentrated in the West. However, this is about to change dramatically.

As the heat dome shifts and recalibrates over the South and southeast, record-breaking temperatures are expected as early as Friday in cities like Atlanta and Raleigh, where temperatures could climb to near 100 degrees Fahrenheit. Over the weekend, record highs above 100 degrees are anticipated from Arkansas to coastal Georgia.

As the heat dome progresses northward, the Ohio Valley is likely to witness record-breaking heat on Monday, followed by the Mid-Atlantic on Tuesday. Subsequently, more record-breaking heat is expected in the East.

To evaluate the potential threat of these predicted temperatures, the National Weather Service has devised a new HeatRisk product, which assigns levels from 0 to 4. Most areas in the Lower 48 states are projected to experience at least Level 2 or 3 HeatRisk over the next week as the heat dome evolves.

The most extreme conditions, classified as Level 4 or "extreme," are expected in large portions of Missouri, Illinois, Indiana, Kansas, Iowa, Michigan, Ohio, West Virginia, and Georgia. Cities such as Des Moines, St. Louis, Chicago, Indianapolis, and Atlanta fall into this category.

Meanwhile, a Level 3 or "major" HeatRisk level is forecasted for Pittsburgh, New York City, Washington, Nashville, Little Rock, and Wichita. These HeatRisk levels take into account the unusualness of the heat, its duration, and its potential health effects. The Weather Service stresses that individuals without adequate cooling and hydration, such as outdoor workers, the homeless, older adults, and those without access to air conditioning, are particularly at risk.

It's not just the high temperatures but also the humidity that make this episode potentially hazardous. Heat indexes, which factor in humidity to determine how hot it feels, are predicted to reach 100 to 110 degrees across the South by the weekend, potentially exceeding 110 degrees in areas near the Gulf of Mexico. The heat dome will generate multiple days of heat indexes exceeding 100 degrees in regions stretching from Texas to Washington, and even as far north as Iowa and the lower Great Lakes.

This heat dome, which formed in May and has already exhibited stubborn persistence and unseasonable intensity, has contributed to historic heat in Mexico, the Desert Southwest, Texas, and Florida. The outlook ahead suggests that this heat dome will continue to influence most of the Lower 48 states, resulting in warmer to much warmer than normal weather until at least the end of June.

As this intense heat wave takes hold, it is crucial for individuals to stay hydrated, stay indoors if possible, and take necessary precautions to protect themselves from the scorching temperatures.