Heat wave latest: How long the dangerous temperatures will last

The first-ever excessive heat warning was issued in Caribou, Maine.

Dangerously high temperatures are hitting 14 states across the Midwest and Northeast on Wednesday as an unrelenting heat wave continues.

Record highs were shattered in the Northeast on Tuesday, including a scorching 97 degrees in Manchester, New Hampshire, and 94 degrees in Scranton, Pennsylvania.

On Wednesday, temperatures are forecast to soar to 94 degrees in Detroit and Pittsburgh; 95 degrees in Syracuse, New York; 93 degrees in Boston; and 97 degrees in Concord, New Hampshire.

The extreme heat will even stretch as far north as Maine. In Caribou, Maine, where the temperature is forecast to hit 96 degrees, the National Weather Service issued its first-ever excessive heat warning. If it does reach 96 degrees in Caribou, it would tie a record for the hottest day ever in the month of June, a record that dates back to June 29, 1944.

The record heat will continue in the Northeast over the next few days, with Thursday forecast to be the hottest day along the Interstate 95 corridor.

The dome of high pressure that is causing all the record heat will then move back into the Ohio Vally by the end of the week and into the weekend. This will bring back the dangerous temperatures to cities like Chicago, which is forecast to reach 96 degrees on Saturday.

There are hundreds of deaths each year in the U.S. due to excessive heat, according to CDC WONDER, an online database, and scientists caution that the actual number of heat-related deaths is likely higher.

Click here for tips on how to stay safe in the heat.