If you’re heading out to a barbecue Monday or to other Independence Day festivities make sure you bring your umbrella and maybe plan on getting an early start. Widespread rain could put a damper on the July 4th holiday.
"If you're interested in barbecuing I recommend the earliest start you can get away with," said NBC10 First Alert Weather chief meteorologist Glenn "Hurricane" Schwartz. "Everyone is going to have a rainy night."
A Flash Flood Watch was put into effect for much of the Philadelphia region as clouds built Monday afternoon. Rain began moving in from southwest to northeast by later Monday afternoon into evening as temps push toward 80.
Showers moved into southern Delaware by early afternoon and could spread into Philadelphia as well as south and east of the city by 4 p.m.
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The NBC10 Weather Team recommends that anyone heading outdoors for a barbecue or another event in Philly or south and east of the city be prepared to possibly get wet.
"You should have the umbrella ready to go," NBC10 meteorologist Erika Martin.
With conditions soupy, heavy thunderstorms could strike Delaware and other parts of the region by early evening but overall this should be a mostly rain event.
"Every hour that goes by after, let's say 5 o'clock, the chance of rain gets higher, the chance of more significant rain gets higher," said Glenn. "We're not talking about downpours but it's going to be a whole lot nicer at 4 o'clock than it will be around 8 o'clock."
With the potential for embedded thunderstorms Monday evening/night, there is the concern for thunder and lightning.
"Everybody will see rain, it will probably get heavier in Delaware than it does elsewhere," said Glenn.
The threat of rain caused some municipalities to postpone fireworks for Monday night.
The Wawa Welcome America July 4th fireworks on the Benjamin Franklin Parkway remain scheduled for 10 p.m. Organizers have a strict protocol in place in case of lightning. If there is a lightning strike within 10 miles of the venue, stage technicians will be placed on alert. If there is a lightning strike within eight miles, rigging, lighting and camera tower staff will be moved to ground level and performances will be temporarily halted. A Public Safety Policy Group will then gather to discuss a possible Parkway evacuation depending on the severity of the storm.
The event also has a high wind policy. If winds reach higher than 40 mph, all show operations will cease and the stage area will be evacuated. If they reach higher than 50 mph the entire venue will be evacuated.
For those attending the concert, you're allowed to bring umbrellas as long as they're not beach umbrellas or have a sharp or pointy top. Tents, canopies and camping equipment are also not allowed.
The showers will continue on and off overnight into Tuesday morning -- with the potential for severe storms between 4 to 7 a.m. -- before the system finally moves out Tuesday afternoon. After the rain the next issue will be the heat.
"We could have some of the hottest, most excessive heat we’ve seen Wednesday through Saturday," meteorologist Karen Thomas said.
Wednesday’s high is expected to push toward 90. More 90s are expected through Saturday. Stay with NBC10.com for the latest updates on 4th of July weather.