As the astronomical summer begins, an intense heat wave continues to blanket the eastern United States, resembling the scorching dog days of summer. The Ohio Valley, mid-Atlantic, and parts of New England are experiencing soaring temperatures in the 90s Fahrenheit, well above the historical average.

AccuWeather's long-range team of meteorologists has been warning about this prolonged heat since early June, predicting temperatures above the norm throughout the weekend. The sweltering conditions are expected to put a strain on residents and electrical infrastructure.

Cities in the mid-Atlantic region, including Washington, D.C., may even reach record-breaking temperatures of over 100 degrees Fahrenheit by the weekend. On Sunday, the capital city is projected to hit a scorching 101 F, surpassing the previous daily record of 98 F set in the 1980s and marking the first triple-digit temperature since August 2016.

AccuWeather meteorologist Alex Duffus warns that the Ohio Valley and Northeast will see daily temperature records being challenged on Thursday, with high temperatures ranging between 90 and 100 degrees Fahrenheit. The region faces an increased risk of heat-related illnesses.

AccuWeather's exclusive HeatWave Counter and Severity Index™ rates the Raleigh heat wave as "moderate," while both Chicago and Philadelphia face a "strong" heat wave. As the lack of rain persists and humidity increases, the AccuWeather RealFeel™ Temperatures are expected to climb well over 100 F, leading to discomfort for people engaged in outdoor activities.

Residents are advised to stay hydrated and take breaks from the heat while working outside during the day. Overnight temperatures will remain elevated, with some locations in the Northeast struggling to drop below 80 degrees, potentially causing strain on the heart as the body tries to regulate its internal temperature.

The high-pressure zone building over the East is expected to bring little or no rainfall to much of the Eastern Seaboard and mid-Atlantic region, worsening the already sweltering conditions and leading to poor air quality. Forecasts indicate that air quality levels may be unhealthy for vulnerable groups, such as children, older populations, and those with respiratory conditions, throughout the week.

AccuWeather Meteorologist Renee Duff warns of deteriorating air quality along the Interstate 95 corridor from Washington, D.C., to Boston, attributing it mainly to ozone. Residents are urged to stay informed and take necessary precautions during this period.

In the Ohio Valley and interior Northeast, sporadic thunderstorms may provide some relief from the heat and improve air quality levels. However, some of these storms can turn severe, bringing hazards like hail and gusty winds.

Relief from the heat is expected in a few days as a cold front approaches the Ohio Valley and Northeast over the weekend and early next week. This pattern change will bring slightly cooler temperatures and lower humidity levels, assisting in the recovery from this prolonged heat wave. Thunderstorms accompanied by heavy downpours may cause localized flash flooding in some areas.

AccuWeather meteorologist Alex Duffus advises that by late weekend, the cold front will progress eastward across the Great Lakes and New England states, providing relief from the heat and humidity for residents in the Midwest and interior Northeast into early next week.

The AccuWeather team continues to monitor the situation, providing advanced and hyperlocal severe weather alerts through the Premium+ subscription on the AccuWeather app to ensure the safety of subscribers and their families.

Note: This article is based on information provided by AccuWeather and includes additional reporting by AccuWeather meteorology intern Thomas Witte.