An active, unsettled, humid, and warm weather pattern will lock in over the Philadelphia and New York City metropolitan areas today on through this week as a series of weakening low pressure systems will run into a powerful upper level low over the northwestern Atlantic. As a result, showers and thunderstorms capable of very heavy downpours will be in place throughout the region while temperatures will vary from east to west from the 70's to upper 80's for highs.
Today, a weakening area of low pressure will drive to the east and collapse before reaching the New Jersey coast. Periods of rain this morning will give way to scattered cloud cover by this afternoon. An isolated shower or thunderstorm will remains a threat this afternoon as mid level disturbances lift through. Winds will be from the south at 5 to 10 mph. Temperatures will rise into the mid to upper 70's along the coast and upper 70's to lower 80's throughout the rest of the region, especially in the Delaware River Valley.
Tonight, broken to overcast cloud cover can be expected with some fog possible towards morning. A few widely scattered to isolated showers or thunderstorms are a threat. Winds will be from the south at 5 to 10 mph. Temperatures will fall into the mid 60's for lows.
Tomorrow on through Friday, a series of weakening low pressure systems will lift through the region with a stalling warm front. Scattered to broken cloud cover can be expected with periods of showers and thunderstorms. The thunderstorms will be capable of very heavy downpours, frequent lightning, hail, and wind gusts over 40 mph. Low temperatures will be in the mid to upper 60's through the period. High temperatures will be in the mid to upper 70's over Long Island, lower to mid 80's over the New York City metropolitan area and the New Jersey coast, and mid to upper 80's over the Philadelphia metropolitan areas.
High pressure will return for Saturday and Sunday with clear skies to scattered clouds. Temperatures will range from the mid to upper 60's for lows and lower to mid 80's for highs.