The blocking pattern that has given us the extended mild and dry pattern will weaken a bit but continue to block the progress of a frontal boundary and will likely also block the northeast movement of tropical storm Joaquin.

Heavy rain for tonight (Tues) will  likely be more focused west and north of Philadelphia, but we will still receive some moderate to heavy rain, tapering Wednesday afternoon.

The front stalls to our south  and areas of low pressure move along the front, bringing more rain Thursday into Friday.

Tropical storm Joaquin may strengthen to hurricane status before moving into the Carolinas or even Delaware sometime between Friday and Sunday.    This situation needs to be watched, since heavy rain and high winds are possible.