Humid and Unsettled Conditions in Place

A stalling back door cold front will stall over the Philadelphia and New York City metropolitan area Tuesday and linger over the region through Thursday leading to the region being bisected between a humid, warm tropical air mass over the Philadelphia metropolitan area and a humid, cool Marine air mass over the New York City metropolitan area.

Tuesday through Thursday, the back door cold front will waver over the region leading to scattered to overcast cloud cover and a threat for scattered showers and thunderstorms.  The thunderstorms will be capable over very heavy downpours, frequent lightning, wind gusts over 40 mph, and hail.  Winds to the east of the boundary will be from the east at 5 to 15 mph and to the west, southwest at 5 to 15 mph.  Temperatures will vary significantly throughout the region.  Low temperatures will range from the lower to mid 50's over Long Island to the upper 50's to lower 60's over southeastern Pennsylvania.  High temperatures will range from the lower to mid 60's over Long Island and southern Connecticut; upper 60's to lower 70's over the New York City metropolitan area, the Hudson River Valley, and coastal New Jersey; mid to upper 70's over the Delaware River Valley, Philadelphia metropolitan area, and northeastern Pennsylvania; and upper 70's to lower 80's over southeastern Pennsylvania.

A powerful cold front will drive through the region on Friday with widespread showers and thunderstorms.  The rainfall from the passage of this cold front will range from one to three inches leading to the threat for urban and flash flooding throughout the region along with very poor driving conditions in the morning and evening.  The slow moving cold front will clear the coast by early Saturday morning and drive the humid air mass into the Atlantic Ocean.  Temperatures on Friday will range from the lower to mid 60's for lows and lower to mid 70's for highs throughout the region.

High pressure will take hold Saturday on through Monday with scattered cloud cover and tranquil weather conditions.  Temperatures will fall back to near to slightly below normal levels with low levels of humidity.  Temperatures will range from the lower to mid 50's for lows and upper 60's to lower 70's for highs.