Building heat and humidity will create a tropical steambath for the Ohio Valley and East as June transitions to July.
The return of 90-degree heat is in the offing for many communities across the Ohio Valley, Carolinas and mid-Atlantic to start the week of Independence Day.
Even parts of the Northeast will crack the 90-degree mark during the first couple days of July.
All of the Northeast, however, will join the rest of the East and Ohio Valley in enduring oppressive humidity, which will add to the discomfort and danger of the soaring temperatures.
The building heat and humidity will come after an area of high pressure keeps humidity levels comfortably low in the Northeast and mid-Atlantic this weekend with widespread highs in the 80s.
The exception to the low humidity will be places toward the eastern Great Lakes with steamy air already present this weekend throughout the Ohio Valley and Midwest, helping to fuel daily thunderstorms.
Highs in the 80s will also dominate the Ohio Valley this weekend.
As the high shifts eastward, the door will open for warmer and more humid air to pour toward the East Coast. At the same time, tropical development will continue to be monitored off the coast of the Southeast.
Tropical is actually how some will describe the upcoming weather in the Ohio Valley and East.
With high humidity already in place, 90-degree heat will become widespread throughout the Ohio Valley Monday and Tuesday.
Humidity will steadily increase across the East from Monday through Wednesday. Highs in the 90s will build over the Carolinas on Monday, then the mid-Atlantic and parts of the Northeast Tuesday and Wednesday.
New York City will come close to recording its first 90-degree day of the year Tuesday and Wednesday. The current record for the latest such occurrence is July 26, 1877.
However, when the humidity is factored in, AccuWeather.com RealFeel® temperatures at midweek may be approaching 100 F in New York City.
Dangerous triple-digit RealFeel temperatures are also in store for Philadelphia; Washington, D.C.; Baltimore; Roanoke and Richmond, Virginia; Raleigh and Charlotte, North Carolina; Charleston and Huntington, West Virginia; Louisville, Kentucky; and Nashville, Tennessee, for the first part of the new week.
While actual temperatures will fail to do so in many Northeast communities, RealFeel temperatures will have no trouble cracking the 90-degree mark to start July.
The heat and oppressive humidity will create dangerous conditions for those planning to engage in strenuous outdoor activities. Remember to drink plenty of water, wear light clothing and avoid such activities during the midday and afternoon hours (the hottest time of the day).
When the blazing sun is shining, remember that vehicles can become death traps for children and pets.
As is the case over the Ohio Valley this weekend, cooling thunderstorms will be around daily across most of the East and Ohio Valley to help ease the heat.
However, the threat of severe weather will shift from the central Plains and western Great Lakes on Monday to the Ohio Valley on Tuesday as a cold front slices into the tropical steambath.
AccuWeather.com meteorologists will be monitoring the potential for drenching and gusty thunderstorms to reach the East at midweek as the front pushes toward the coast.
Latest indications point toward the front clearing the Northeast and mid-Atlantic coasts by Friday, giving way to a comfortable Independence Day for both these regions and the Ohio Valley.