Sun 07:15 PM Forecast Review — Having gone with last night’s CMC, NBM and ICON models, my forecast high was not reached. The high temperature was about 91-92º today. The low probability of light scattered showers continues; most areas will be dry.
A cold front will move through Sunday evening. Before that time, high temperatures may reach 94º-95º in the Philadelphia area today around 3-4 PM. Still low dew points near 60º or less, keeping it more comfortable than a typical summertime ninety degree day in Philadelphia.
Some models (HREF, Canadian HRDPS) have a low probability of a widely scattered shower or thundershower making it into Philadelphia between 6 and 9 PM. There’s just enough convective available potential energy (CAPE), marginal instability and available moisture. Most areas won’t see any rain.
Sun 08:35 PM Forecast Review — The thunderstorms came through close to schedule about 6:45 PM . This afternoon’s models only showed CAPE values of 580 joules/kg, not the 1300 predicted by yesterday’s HRRR. So storms were typical, not severe.
from yesterday …
The forecast is on track with rain on Sunday, starting between 6 AM and 8 AM.
Most models have the rain becoming more episodic in the afternoon, with lines of showers moving through with breaks in the rain . Heaviest rain is now expected west of the Philadelphia area. QPF about 0.6 inches for Blue Bell. It will become WINDY. High near 68º
A final line of showers and thunderstorms appears to be timed between 5-7 PM in the immediate PHL area with the cold front passage. Available thermodynamic energy (“CAPE”) values may exceed 1300 joules/kg which could cause some strong storms from Philadephia and eastward.
