The Philadelphia and New York City metropolitan areas finally have a morning that starts out with clear skies, light winds, and comfortable temperatures as the region gets a break break in unsettled conditions. Unfortunately, these pleasant weather conditions will not last long.
Clouds will be slowly on the increase through this afternoon as temperatures rise to near normal levels into the lower to mid 70’s over the interior and upper 70’s to around 80 degrees for a high today. Winds will be light from the southwest. However, trouble is already brewing over the Great Lakes that will lead to very unsettled conditions for the northern Mid Atlantic this weekend.
A strong upper level disturbance over the central Great Lakes down through the Tennessee River Valley will intensify and form an upper level low this evening over Virginia. The formation of this upper level low pressure system will lead to a surface low pressure system to take shape off the Delaware coast this evening. As a result, clouds will rapidly increase over the Philadelphia and New York City metropolitan area with scattered showers developing along the coast. These showers will initially be weak but will be capable of heavy downpours later tonight as the upper low intensifies.
This upper level low pressure system will continue to mature and intensify while sitting over the Philadelphia and New York City metropolitan areas tomorrow on through Monday morning while the surface low pressure system meanders over the New Jersey coastal waters before tracking into the northern Hudson Valley by Monday morning. This pattern will lead to variable to overcast cloud cover and periods of scattered showers. Depending on the development of upper level disturbances around the upper level low, some locations will experience long periods of rainfall while other areas will remain cloudy but dry. This forecast period is highly volatile as a result. What isn’t in question is the cool temperatures as a maritime northern Atlantic air mass invades tonight and remains in place through this weekend. Temperatures will range from the upper 40’s to mid 50’s for lows and mid 50’s to mid 60’s for highs through the weekend.
By Monday afternoon, high pressure over Quebec will build south and take control of the weather pattern through much of next week. This high pressure system will produce tranquil weather conditions with temperatures averaging near to slightly below normal. Temperatures will range from the upper 40’s to mid 50’s for lows and mid 60’s to mid 70’s for highs.