Mostly sunny skies will continue into early this afternoon, before some clouds increase ahead of an approaching cold front and upper-level trough later today. Enough lift and ascent will likely result in some showers and thunderstorms late this afternoon or this evening. High temperatures will reach the lower to middle 70s away from the coast by early this afternoon. Over Long Island and Connecticut coastal southerly winds will keep high temperatures in the middle to upper 60s.
Organized severe thunderstorms are not anticipated due to a lack of low-level moisture or instability. A more stable marine airmass from sea-breezes later this afternoon may also cause thunderstorms to weaken as they approach the coast. But strong, unidirectional shear and steep low and mid-level lapse rates could cause a few strong thunderstorms with some gusty winds. An isolated damaging wind gust is possible, especially over the Delaware River Valley. Heavy downpours, cloud to ground lightning, and small hail are also possible.
Any showers and thunderstorms will come to an end during the late evening hours, with the cold front passing east of the region. As a result, a much cooler airmass will be moving into the region. Skies will become clear overnight with temperatures dropping into the 40s late tonight.
Tomorrow, an anomalous upper-level low will bring a much cooler airmass into region. Plenty of sunshine during the morning hours will mix with more clouds in the afternoon. Some instability with passing upper-level disturbance north of the region could cause a few widely scattered showers or sprinkles during the late afternoon hours, especially northwest of New York City. High temperatures will be in the upper 50s to lower 60s.