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.
Any signs the dry pattern may break and give us some much needed rain?
This is beginning to remind me of the drought that we had that started in May 2000. Then again, climatology is not my forte.
There’s a front that moves through on Wednesday, possibly with some showers.
The first real chance of rain is Friday into Saturday. Some models have as much as 1 inch of rain, some less than 1/2 inch. Way too early to be sure. I was planning to post a Memorial Day weekend outlook post by end of day Tuesday.
We’re definitely in a dry pattern here and these patterns can become well-entrenched and self-perpetuating. A lack of soil moisture can become a negative feedback loop for thundershower formation. We may need to wait for some tropical system to shake up the pattern.
(Last year, we were dealing with drenching 3-6 inch rains and severe thunderstorms May and June!)