PHILADELPHIA (WPVI) --TONIGHT: Partly cloudy and very warm. You will also feel an increase in the humidity as the night progresses. Lows in the 60s.
FRIDAY: You will certainly notice the high dewpoints when you step out in the morning, but as we go through the day drier air should one again mix down and limit the extent of afternoon humidity. Highs tomorrow will reach 90 and with a weak disturbance in the upper levels of the atmosphere passing by to our northwest, we could see some pop-up t'storms in those areas come the afternoon. Highs at the shore only in the mid 70s with a refreshing sea breeze.
SATURDAY & SUNDAY: We keep the sunshine and the heat with just a few clouds mixing in. The peak of our heat will come Saturday with a high of 92 and we'll notch things down just a touch heading into Sunday with a high of 90. Both days are mainly dry, but a pop-up t'storm in far northern areas due to terrain effects is possible. Highs at the shore will be much cooler: in the low to mid 70s.
MONDAY (MEMORIAL DAY): The problems arise on Memorial Day as a subtropical or tropical low pressure moves into the southeastern U.S. To the north of it we will fetch southeasterly winds that will bring in clouds, higher humidity, and the threat of showers/t'storms. While it doesn't look like a complete washout at this point, there will be very little in the way of sun and showers off and on through the day. Temps will be much cooler---only 79 in Philadelphia with upper 60s at the shore.
TUESDAY: Clouds stick around with a little more sun peeking through after the unsettled holiday. There could be an isolated shower or downpour around, but far less than Monday. Highs jump back up to 85.