AccuWeather: Historic heat wave begins

PHILADELPHIA (WPVI) -- Highs are forecast to climb above 100 degrees for three days in a row this week.

TUESDAY: Clouds mix with sunshine, high 92.

WEDNESDAY: A steamy start to July. It's hot and humid, high 98. An Extreme Heat Watch begins with heat index values likely between 100-105 degrees.

THURSDAY: Another very hot day with humidity still elevated, high 103. The Extreme Heat Watch continues, with heat index values likely between 105-110 degrees.

FRIDAY: High heat and humidity, high 103. Heat index values once again between 105-110 degrees. An isolated thunderstorm can't be ruled out.

SATURDAY (4TH OF JULY): Hot and humid with the threat for thunderstorms later in the day, high 100. The Extreme Heat Watch continues with heat indices likely near 105 degrees.

SUNDAY: Clouds some sun. With some late-day storms. It stays hot, high 95.

MONDAY: Scattered storms, high 89.