Rain clouds will threaten all holiday weekend, starting Saturday morning.
A line of thunderstorms started sweeping to the D.C region early, starting from the north and tracking south to southwest against the usual storm pattern. Rain will drop across the area until early afternoon. The National Weather Service warned of strong thunderstorms with accompanying lightning across Frederick, Montgomery, Loudoun, Prince William, Fairfax and Fauquier counties for Saturday morning.
After those storms pass, temperatures will be into the mid-80's and air will stay humid. On Sunday, the main rain threat will come with afternoon thunderstorms. If showers do develop, they will be sporadic. Chance of rain late day Sunday is around 30 percent.
For Monday, Labor Day, Chuck Bell says the weather will be "slippery at best." There is at least a 60 percent chance of showers that day. For those planning outdoor picnics, it would be prudent to come up with a backup plan.
Following the long weekend, fall's first week is shaping up to be a wet one. The approach of a cold front from the Midwest and a plume of tropical moisture from the Gulf of Mexico means our rain chances will climb substantially. Tuesday and Wednesday, with 1" to 3" of rain possible during that time.