This morning's low clouds in the Delaware Valley is a sign that high pressure's influence over our region is starting to wane slightly. The dry air that the high was funneling into our region is now moistening up a bit with a more consistent onshore flow, which resulted in deck of low clouds pushing inland off of the Atlantic last night. We're still enjoying relatively fair weather but the core of high pressure is no longer overhead as the center of high pressure is nudging farther into the Atlantic. Despite an onshore flow the past few days, the high's influence was able to mitigate the influence of Atlantic moisture and thus was allowing for nice days.
That's no longer the case...
The result is that the next couple of mornings are likely to bring us a deck of low clouds, perhaps some fog in spots, as moisture streams in off of the Atlantic overnight. That push of moisture will likely be more pronounced on Tuesday (see the bottom map) than it will be tomorrow morning for people in Central and Western Pennsylvania -- but as far as we're concerned it does mean the next couple of mornings will likely be cloudy as the influence of the Atlantic rules the roost. The increased influence of the Atlantic on our weather will likely mean clouds will be slower to burn each of the next two days...with Tuesday holding a higher risk of remaining cloudy most of the day.
We're watching that cutoff low in the Southeast as it rambles towards us for later Tuesday and Wednesday. Showers will spread towards us for later Tuesday and Wednesday, with some thunder possible as the upper low moves nearby. By the time it reaches us, the low will not be as cold aloft as it was over the South as the low will be a good bit weaker; however, it will still have enough pop with it to produce showers and storms as it moves through. So, no record lows or record cold highs for our foreseeable future...but a bit more cloudcover and an increased shower risk as we move towards midweek.