Hottest weather of season on tap for Northeast as record-challenging heat wave builds

By Alex Sosnowski, AccuWeather senior meteorologist

As heat expands across the northeastern United States, highs near the century mark will be common, with some locations experiencing dangerously high AccuWeather ReelFeel® Temperatures well above 100 F -- but not before what's left of Barry sweeps through with localized flooding downpours.

While temperatures may be briefly held back in areas that receive a thorough drenching for a day or so, intense July sunshine, combined with a northward retreat of the jet stream will allow an impressive heat wave to build even for midsummer standards.

In the northern U.S., a heat wave is generally that which brings three or more days in a row with highs of 90 F.

"The combination of sunshine, temperature, humidity levels and other factors will push AccuWeather RealFeel® Temperatures well into the danger level past 105 degrees during the late morning and afternoon hours," according to AccuWeather Senior Meteorologist Brett Anderson.

"Actual temperatures in some of the major cities, such as Washington, D.C., Baltimore, Philadelphia and New York City are likely to peak within a few degrees of the century mark at the peak of the heat wave this weekend," Anderson said.

At this level, temperatures will be 10-15 degrees above average even for the middle of the summer.

"Cooling demands will surge with the intense heat wave," according to AccuWeather Lead Long-Range Meteorologist Paul Pastelok.

Among the cities that could break or challenge records on Saturday is Manchester, New Hampshire, which is forecast to hit the century mark. The daily record high in Manchester for July 20 is 94 F set in 1949. Manchester's all-time record is 103, set on July 22, 2011.

Farther south, Newark will challenge its daily record of 100 degrees. The mercury is forecast to soar to 101 there on Saturday. As hot as it will be this weekend in the New York City area, the Big Apple's all-time high temperature record of 106, set on July 9, 1936, is not in danger of falling. With a forecast high of 100, Philadelphia could shatter its daily high of 97 on Saturday.

Washington, D.C., will also swelter with a forecast high of 101, however the nation's capital shouldn't break its daily and all-time high of 106 hit on July 20, 1930, about 12 years after the mercury hit 106 in 1918.

Other spots on the East Coast that will feel the heat and challenge records on Saturday include Atlantic City, New Jersey, which is forecast to hit 100, a temp that would break its record of 98 for the day, and Richmond, Virginia, which is forecast to hit 101. Its record high for the day is 103.

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People should avoid strenuous activity during the peak of the heat and when the sun is high in the sky. Be sure to stay hydrated by consuming non-alcoholic fluids at regular intervals.

The temperature of paved and concrete surfaces can be dozens of degrees higher than the air temperature. Not only does this contribute to a buildup of excessive heat in urban areas, but can be a safety hazard.

The hot pavement can also burn the bare feet of young children and pet's paws.

Motorists on the highway are reminded to reduce their speed during extremely hot weather. Driving at high speed, excessive braking and weaving in and out of traffic during very hot weather can cause the tire temperature to exceed manufacturer's safety limits and lead to a blowout.

There will be rounds of thunderstorms prowling the northern tier of the U.S. through this weekend. It is possible that some communities around the Great Lakes and northern New England get a break every now and then as these storms race through.

The same pattern can bring severe weather in the northern tier as well in the form of long-lived thunderstorm complexes.

"Temperatures are forecast to throttle back to seasonable levels or even slightly below average for a time next week in the East as heat shifts to the western U.S.," Pastelok said. "There should also be a substantial drop in humidity in the Northeast next week."

Highs most days next week will range from the middle 70s over the higher mountains to near 90 in southeastern Virginia.