As heat peaks for most of East, these cities are set to hit 100 degrees

More than 150 million people in the eastern U.S. are under heat alerts as of early Tuesday – including about 75 million under extreme heat warnings from North Carolina to Maine.

It will be the peak day of this heat wave for much of the Interstate 95 corridor, with a rather large swath of the region at risk for near or above 100-degree temperatures Tuesday afternoon.

Cities that could reach the century mark include Boston; Hartford, Connecticut; New York; Philadelphia; Baltimore; D.C.; and Raleigh, North Carolina. Portions of a dozen eastern states are forecast to see temperatures of 100 or higher.

Highs should be a bit warmer than Monday’s in most locations in the mid-Atlantic and Northeast, while they’ll be a little lower over the Ohio Valley. Extreme HeatRisk will be widespread across all of these regions, with a focus from Indiana and Ohio to the coastal Mid-Atlantic.

Among the hottest spots on Monday afternoon was Newark, New Jersey, where it reached 101 degrees. Highs of 100-plus also made it all the way to northern New York as high humidity swamped the region.

Where it doesn’t hit 100 in this stretch, it’ll be close and will feel like it got there. Numerous records are probable again Tuesday after dozens were set Monday. Similar conditions are expected Wednesday before the heat wave begins to abate.

Many locations should approach or surpass 100 on Tuesday afternoon.

The focus of the most intense heat is along the I-95 corridor. The day could offer some truly astounding temperatures for locations that rarely see it get so hot, such as coastal Massachusetts.

If the forecast is realized, Tuesday will be the hottest day on record for June in Hartford. In Boston, a high of 102 would also set the record for hottest day in June and become one of the hottest days in any month. Philadelphia’s record for June is 102, which could be tied if temperatures there overperform the forecast.

When factoring in the high humidity, thanks to stifling dew points at or above 70, heat index values will rise about 10 degrees higher than the actual temperature. That equates to widespread apparent temperatures of 105 to 115 during the afternoon from Florida to Maine and across parts of the Ohio and Tennessee valleys.

It’s also some of the hottest weather in the country. Only a couple of locations in the Desert Southwest will be as hot or hotter, and with lower humidity.

Potential record highs ranging from the mid- to upper 90s will surround the hottest locations on Tuesday.

Even in the high country of the Appalachians, there won’t be much escape. Mountainous locations in West Virginia through North Carolina should mainly reach the low and mid-90s.

In Vermont, a high temperature of 97 is forecast for Burlington in the far north of the state. On Monday, it hit a record 99 there while dew points rose to near 80 – basically unheard of in the region.

In addition to the dozens of record highs, more than 100 warm record lows were set early Tuesday, as long as they hold through the whole day.

Temperatures remained in the 70s to above 80 across most of the same zones. Lack of overnight cooling is a stark signal of human-caused climate change and can quickly make heat waves more dangerous since it removes the opportunity for the body to easily cool while at rest.

Over the past week, much of the country has witnessed their hottest temperatures of the year so far.

The heat ramped up in the intermountain west late last week before shifting eastward.

On Monday, Plattsburgh in far northern New York and Lebanon in New Hampshire both tied their all-time highs for any month with 101 and 98, respectively.

Newark, just outside New York City, reached 101 on Monday, a record for the date. The cities of Westfield, Massachusetts, and Raleigh are among the handful of additional locations that reached 100.

This follows 100-degree readings as far north as South Dakota, Minnesota and the northern Ohio Valley during this country-crossing heat wave.

The most intense heat will get squashed farther to the south and east Wednesday. Record high potential should focus from around New Jersey south to the Carolinas.

The footprint of 100s should shrink considerably compared to Tuesday, but a corridor of 100-plus could focus on eastern North Carolina to southeast Virginia, with the potential for a smattering of century marks elsewhere.

Philadelphia and Washington should see highs in the mid-90s to around 100, which could set some additional regional daily high-temperature records.