Throughout the afternoon and evening hours yesterday, widespread showers and thunderstorms developed across Pennsylvania and New Jersey, slowly expanding and spreading northward into New York along and north of a stalled frontal boundary over the area. These storms were generally non severe but produced heavy rainfall, with radar estimates showing 3/4 to 1.5 inches of rain in most of northern NJ, locally up to 2-3 inches especially in Morris county. Locations east of NYC, however, have yet to see more than a few isolated storms.
Most of the heavy rain and storm activity shifted north into NY state as expected, although a severe thunderstorm developed over southeastern PA and is slowly tracking northeast towards western-central New Jersey. The stalled frontal boundary is currently located near northern NJ into NYC on a west-east axis, and the storm is expected to weaken in severity once approaching NYC, although it will be capable of producing heavy rainfall over the next few hours especially west and southwest of NYC, with gusty winds also a risk.
The frontal boundary will gradually lift north as the wave of low pressure organizes over the region and tracks northeast, with occasional showers/storms continuing through the mid-late morning, mostly north/west of NYC, while the heaviest rain stays north of the area. Another 1/2 to 1 inch of rain is expected north and west of NYC, with less than 1/2 inch to the east. Most of the current heavy rain activity should clear the region in the morning, although additional scattered storms are expected to develop in the afternoon and evening, which also may be capable of locally heavy rain. The next update will be posted later this morning.