The prize for an oppressively hot, humid and rainy Sunday was a spectacular sunset that cast a peculiar glow over the Philadelphia area and beyond.
Sunday's dusk stood out because of the unusual mammatus clouds that hovered in the sky after the storm broke. They form when cold air condenses at the base of a rain cloud. Heavy water and ice particles sink and heat up, leading to the appearance of drooping bulbs on the underside of the large storm cloud, according to the UCAR Center for Science Education.
If the timing is just right with a sunset, it can produce the brilliant effect seen Sunday night in much of the Delaware Valley and South Jersey.
The ominous appearance of mammatus clouds is generally a sign that the worst of a storm has passed, although the instability in the atmosphere could still mean lightning, rain and hail are possible. The clouds are often associated with turbulence during flights. Sunday's storms contributed to disruptions and delays at Philadelphia International Airport.
On the bright side, people from across the region took stunning photos and videos of the sunset.
Here's a look at the National Weather Service forecast for the week.
Monday: Mostly sunny, with a high near 81. North winds around 15 mph, with gusts as high as 25 mph. At night, mostly clear with a low around 64.
Tuesday: Sunny with a high near 86. At night, partly cloudy with a low around 63.
Wednesday: Mostly sunny with a high near 86. At night, partly cloudy with a low around 70.
Thursday (Fourth of July): A chance of showers and thunderstorms after 2 p.m. Partly sunny, with a high near 92. Chance of precipitation is 30%. At night, mostly cloudy with a low around 74. A chance of showers and thunderstorms.
Friday: A chance of showers and thunderstorms after 2 p.m. Partly sunny with a high near 91. Chance of precipitation is 40%. At night, mostly cloudy with a low around 75.
Saturday: A chance of showers and thunderstorms. Mostly sunny with a high near 93. At night, a chance of showers and thunderstorms. Mostly cloudy, with a low around 74.
Sunday: A chance of showers and thunderstorms. Mostly cloudy with a low around 74. Mostly sunny with a high near 91. Chance of precipitation is 30%.