Scattered showers will be around on Tuesday. I'm not expecting much in the way of thunder during the daylight hours because CAPE values are minimal, but by evening I wouldn't rule out an isolated rumble of thunder. Highs will ultimately depend on how much sun we receive tomorrow. Our best chance for breaks in the clouds will be during the late afternoon, especially from the city on south and east, and if this occurs I think we can manage the mid 70s in these areas. North and west of Philadelphia will be cloudier, so upper 60s to perhaps 70 looks more likely up there.
Temperatures will be much warmer behind Tuesday's warm front. Wednesday will feature a mix of sun and clouds and highs in the upper 80s. Thursday and Friday are our best chances at 90 or higher. 90 is still possible on Saturday but there may be more clouds around in the afternoon as a cold front begins approaching from the west. That cold front looks to move through Sunday night and bring us scattered showers and thunderstorms for late Sunday afternoon into Monday, and it will put an end to our possible heat wave (3 days or more at 90 degrees or higher).
7 AM 61 degrees, Plenty of Clouds
Noon 68 degrees, Scattered Showers
5 PM high 74 degrees, Scattered Showers
Sunrise 5:36 AM
Sunset 8:21 PM