Will the Dangerous Heat Building in Northeast Last Into August?

By Alex Sosnowski, AccuWeather.com Senior Meteorologist

July 28,2015; 11:18PM,EDT

 

A heat wave will build, then recede in the East this week with the most humid air focused on the Interstate-95 corridor.
The heat may be second only to that of just a little over a week ago, spanning July 19-21.

East Heat on High Much of this Week

The combination of 85-95 F air, high humidity, light winds and intense sunshine will push AccuWeather RealFeel® Temperatures to the triple digits in many locations of the I-95 corridor and the Ohio Valley.
In much of the Northeast, the peak of the heat and humidity will be on Wednesday.

These conditions will make it risky for extended, strenuous physical activity outdoors and can pose a danger for the elderly and those with respiratory problems.
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For some cities in the Northeast, this will not be the first heat wave of the year. A heat wave in the northern states constitutes three days in a row with temperatures hitting 90 F or higher. In part of the New York City area, this will be the second heat wave of the summer season. In Philadelphia, it will be the third. In Washington, D.C., it is the fourth with a month's worth of 90-degree days since early May.
Boston has yet to have a heat wave this year and has struggled to hit 90.
According to AccuWeather Long Range Expert Paul Pastelok, a series of fronts will gradually trim humidity and temperatures across the Midwest and into the Appalachians starting later this week and continuing into the middle of August.

"While humidity levels will drop along the I-95 corridor, daytime temperatures are likely to still climb well into the 80s to the lower 90s after the humidity departs by Friday," Pastelok said. "The most noticeable cooling will occur from the Midwest to the Appalachians."
Less humid air moving into the coastal Northeast this weekend will allow the nights to cool a bit, especially in the suburbs.
In the South, some cooling will reach the southern Appalachians at times, but no lasting relief from hot and humid conditions is likely toward the Gulf of Mexico and Atlantic Coast.
No heat waves are likely from much of the Great Lakes to the coastal Northeast during the first couple of weeks of August.

"There can be a brief spike in temperature and humidity from the Midwest to the Northeast during the first couple of weeks of August," Pastelok said. "These spikes will tend to occur the day of or just ahead of a frontal passage."
The weather during the first part of August will still be warm enough for swimming most days along the Atlantic Seaboard, but perhaps on the cool side around the Great Lakes. High temperatures from New York City to Washington, D.C., will generally be in the 80s beyond this weekend into mid-August. High temperatures around the Great Lakes region will tend to be in the 70s to lower 80s most days during the first two weeks of August.
Ahead of each front will be a round of showers and thunderstorms, including in New England, where pockets of drought continue. Overall though, most places from the Midwest to the mid-Atlantic states will have fewer rainy days during early August, when compared to June and early July.
Pastelok stated that his team will be monitoring the potential for Gulf of Mexico and Atlantic moisture to feed up from the South during the first week of August, and it may be a concern for flooding rain along the I-95 corridor of the mid-Atlantic and Carolinas.