Heat index values at 10 a.m. Friday The entire mid-Atlantic and Northeast I-95 corridor already had heat indices above 100, with Washington, D.C. leading the way at 108. Map courtesy Weather.com - click here for latest hourly update. ( )

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On Thursday, extreme heat and humidity stretched from the Texas/Mexico border to Boston. Weather Underground reported heat indices passed 110 in at least 50 cities. Washington, D.C.’s heat index reached 112, its highest in more than 10 years.

168 record highs were tied or set along with 317 record high low temperatures. St. Louis (103), Chicago (99), Indianapolis (100), Detroit (100), Newark (103), Syracuse (101) and Burlington (97) all set record highs. Emira, New York which climbed to 104, had its hottest day since September 4, 1953.

Graphic illustrating the heat dome the covered a huge expanse of the U.S. Thursday. (Bonnie Berkowitz and Jason Samenow, Washington Post)

The giant area of high pressure - or heat dome - which spawled across such a large part of nation Thursday is getting a south and eastward push by the jet stream today. Interior New England and portions of the upper Midwest get relief, but not the central U.S. and eastern seaboard.

Many cities along the East Coast will soar past 100 today. Weather Underground’s Angela Fritz listed the following cities forecast to come within five degrees of their all-time record highs today:

Boston, Mass.—100°F (forecast) 104°F (record, 1911)
Newark, N.J.—102°F (forecast) 105°F (record, 1966)
Washington D.C.—103°F (forecast) 106°F (record, 1930)
Dulles Airport, Va.—103°F (forecast) 104°F (record, 1988)
Central Park, N.Y.—102°F (forecast) 106°F (record, 1936)
Providence, R.I.—100°F (forecast) 104°F (record, 1975)

The Weather Channel has a nice interactive map highlighting locations forecast to near or pass record highs - focused on the I-95 corridor from Richmond to Boston. Already today, New York’s JFK Airport and Newark have set records for the date, hitting 100 and 102, respectively according to reports.

In addition to stifling heat and humidity in the mid-Atlantic and Northeast, bad air quality is forecast. Code red levels - unhealthy for general population - cover the Washington, D.C./Baltimore region, whereas code orange levels - unhealthy for sensitive groups - stretch from central North Carolina to southern New England.

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