Philadelphia will narrowly miss summerlike heat Thursday and Friday, but it turn noticeably warmer for Mother's Day weekend.
Temperatures will surge into the 80s over much of Virginia, western Maryland and western and central Pennsylvania Thursday into Friday. The Philadelphia area and points to the east will be under the influence of a cool, damp flow of air from the Atlantic Ocean and the Delaware Bay.
A stalled front will be responsible for the temperature split and it will also spark a shower or thunderstorm each day.
The warmth will push in from the southwest this weekend, but right around the same time, moisture will arrive from the Gulf of Mexico.
As a storm system moves along in the warm, humid air from the Gulf, locally drenching showers and thunderstorms are in the offing, along with 80-degree temperatures.
Enough rain could fall in a short time to cause flash and urban flooding problems Saturday.
The wet weather will fade Saturday night as it turns drier just in time for Mother's Day. Sunshine will mix with clouds on Sunday as highs soar into the lower 80s.
Content contributed by Andy Mussoline, AccuWeather Meteorologist
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Residents of the southeastern United States may feel like the calendar has flipped ahead to Memorial Day with warm and muggy weather in place for the start of May.
May is picking up where April left off with record-challenging warmth surging back into the northwestern United States.
Dry days will be hard to come by in the northeastern United States for the first week of May as storm systems bring frequent rain to the region.
Torrential rain triggered flooding across southern Louisiana over the weekend, submerging streets and closing major highways.
Eastern U.S. (1812)
May snowstorm swept from Philadelphia northeastward to Maine. Snow covered ground in New York City; 12" accumulated near Keene, New Hampshire, 9" fell at Waltham, Mass., near Boston.
Severe snowstorm: 33.8" in Havre (24.8 inches of which fell in 24 hours).
New Orleans, LA (1978)
Persistent thunderstorms caused worst flooding in 30 years at New Orleans; lightning ignited an oil storage tank at Covent, LA.