The potential for frosty starts in portions of the region on Monday and Tuesday morning continues to show up in modeling. Both mornings will be pretty crisp across the region, with the potential for a frost greater to our north and west tonight while it will be possible event to the south of the city on Monday night into Tuesday morning as low temperatures could flirt with freezing down into Delaware or interior portions of South Jersey.
Frost advisories are out for tonight for the Lehigh Valley, Berks County, and the Poconos, with probably a similar if not a bit more expansive advisory makeup in the works for tomorrow night.
Above are the projected lows from the NAM computer model for tomorrow morning, with the Tuesday morning temperatures below. Both are quite cold, with the city likely barely above 40 both mornings (the record low for Tuesday in the city is 40) and 30's across the suburbs. Patchy frost looms as a distinct possibility west of the Blue Route and north of the PA Turnpike across the suburbs in Pennsylvania for Tuesday morning, with Monday morning's threat confined mainly to the outer parts of the Philadelphia suburbs (Quakertown, Allentown, Reading, Pottstown, western Chester County). The saving grace for Sunday night could be just enough breeze through the night to prevent temperatures from bottoming out.
Some record lows could be approached the next couple of mornings -- Trenton's record tomorrow is 39, Reading's record low is 36. Wilmington's record low on Tuesday is 36 and we already mentioned Philadelphia's 40. Any of those could be flirted with over the next couple of mornings as one last cold shot for spring meanders on through.