USA National Forecast

Midwest, Mid-Atlantic Threaten Record Highs Sunday As Heat Relief Arrives In New England

At a Glance

A heat dome will threaten record highs from the Midwest to the mid-Atlantic.
Above-average highs combined with the humidity and little overnight relief is leading to dangerous heat conditions.
Temperatures will drop in the Great Lakes by Sunday.

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A dangerous heat wave will threaten record highs in the mid-Atlantic Sunday as parts of New England and the Great Lakes see relief. Some communities in the mid-Atlantic could hit 100 degrees.

Highs Will Set More Records, But Relief Has Arrived For Some

Heat alerts have been issued by the National Weather Service in portions of the Midwest and mid-Atlantic for the dangerously hot conditions. Heat illnesses are most likely in areas shaded in pink, including Philadelphia, Pittsburgh, and Fort Wayne, Indiana.

Some of the hottest conditions will arrive Sunday in the mid-Atlantic.

Relief has begun to arrive in portions of the Great Lakes, New England and upstate New York, and that will last through the weekend. A slow-moving frontal boundary will drift from the Upper Midwest to the mid-Atlantic by Sunday. Thunderstorms are expected along this front.

By Sunday, the Interstate 95 corridor from Philadelphia to Washington, D.C. could see highs approaching 100 degrees in what could be the hottest day of the summer so far.

Several daily record highs are expected. A few cities that could threaten records through the weekend include Baltimore; New York City; Philadelphia; and Washington, D.C.

The southern Great Lakes and Ohio Valley will see a temperature drop Sunday, and the mid-Atlantic might see temperatures trend downward a bit by Monday or Tuesday. That said, it will still feel plenty like summertime.

The Heat Index Is Reaching Triple Digits

Dew points have also increased, meaning it feels sticky and humid. When the humidity is added to the hotter-than-average temperatures, "feels-like" temperatures are even higher. In some areas that means the heat index will rise into the upper 90s or even lower 100s. A few spots around the Potomac could see feels like temperatures in the mid 100s.

Cooler and drier air will arrive in the Great Lakes and Ohio Valley by late Sunday into Monday.

This Heat Will Be Dangerous

The hot daytime temperatures over several days, when combined with very warm low temperatures and humid conditions, is raising the risk of heat illness.

On the map below, areas in orange indicate where people sensitive to heat may be affected Sunday. The red areas are where anyone without effective cooling and/or adequate hydration could be impacted. Purple areas are of the most concern and show where the excessive heat may have wider impacts.

You can see the heat risk maps for other days this week at this link.

Heat illness is a serious concern. Please take necessary precautions to be ready for the upcoming heat.

Linda Lam is a lead meteorologist at weather.com. Growing up in Massachusetts she developed a fascination for winter storms and hurricanes that led her to pursue a career in meteorology.