High pressure is analyzed to the east of New England and just south of the Canadian maritimes, while a warm front has stalled across central Pennsylvania. The ridging has been slow to break which has suppressed the onset and even allowed some sunshine to begin the day for part of the state. Southeasterly winds between these two features continues to advect in a plume of low level moisture in and the column will begin to saturate this afternoon.
As warm moist air advects in with the approaching warm front, rain showers will develop by late morning. A few downpours will develop this afternoon with the help of a mid level shortwave trough passing through and some modest instability (about 100j/kg of mu cape) nosing in during the afternoon.
Weak forcing from an approaching warm front will continue tonight while additional waves of energy work through the area in the mid levels of the atmosphere. Light winds and deep low level moisture will favor areas of fog and drizzle tonight in addition to any lingering showers this evening.
This activity will slowly taper off Saturday morning as a warm front eventually lifts north of the area by midday. The weekend looks mostly dry, with milder and more humid air taking over beginning late Saturday into Sunday. The area will lie in the warm sector of an area of low pressure located northwest of New England – on the periphery of a large western Atlantic ridge. Any shower activity during this period will be isolated at best and more likely farther NW towards the New York Hudson valley and western Massachusetts.
A cold front will eventually sweep through late Monday with a round of strong to severe storms with a second frontal passage likely Wednesday night. Drier weather will make a return by late next week.