Saturday 11:30 PM Update : the models over-predicted the showers today. Tonight’s models have some showers late morning into afternoon Sunday, as the main cold front moves through. High temp only 59.
Again, upper air lows and associated showers and clouds are often poorly modeled. A low confidence forecast .
The bright spots we’re having this morning were expected and predicted.
The models have more low level cloudiness moving back in by this afternoon, with an increase in areal coverage of spotty showers during late morning and afternoon.
Exact placement and timing of showers with an upper air low pressure system is nearly impossible to predict. Instability of the atmosphere is high and any breaks of sunshine become “self-destructive” with the cold pool of air present in the upper atmosphere interacting with the sun-warmed rising air from the damp ground surface.
Update 10AM: More sun than expected today. High temperatures around 71.
As expected, the easterly flow behind the cold front that dropped down Saturday evening has resulted in considerable low-level cloudiness for today, Sunday.
The cloud layer will not be thick, so brightening skies are possible early afternoon, but overall, expect cloudy skies and cool temperatures. Some reduction in cloudiness is possible early evening. High temperatures around 67.
The warm front moved through earlier this morning, but an east-west orientation of the front may allow another batch of showers and thunderstorms to move in here about 11AM-12 PM today. These showers are currently in Lancaster and the HRRR and GFS LAMPS show their making it into the PHL area before dissipating. (They may dissipate before getting here; we’ll see how good the models are.) They will be fast-moving, lasting less than an hour.
The front returns as a cold front later today.
It does appear that the easterly flow on Sunday will result in significant low level cloudiness with some brights spots.
