A series of disturbances will move through our area during the first half of the week which will cause unsettled weather. On Monday, May 21, there will be plenty of moisture flowing through the Delaware Valley, so some periods of heavy rain will be possible. There is a 60 percent chance of showers and thunderstorms, and the high will be in the lower 70s.
A front will approach on Tuesday, May 22, so again there is a 60 percent chance of showers and thunderstorms. However, it will be about 5 degrees warmer, in the upper 70s.
The front will remain over us on Wednesday, May 23, but the atmosphere won't be quite as unstable, so the chance of showers and thunderstorms is a bit lower at 40 percent. I expect to see some periods of hazy sun on Wednesday which will push temperatures up close to 80 degrees.
As the front moves toward the south on Thursday, May 24, hazy sun is expected again with just a 30 percent chance of thunderstorms popping up. The high on Thursday will be near 80 degrees.
High pressure starts to build in on Friday, May 25, and should last through Memorial Day weekend. Clouds will give way to sun on Friday, and it will be warmer, in the lower to mid-80s.
Saturday, May 26, looks mostly sunny and very warm with a high in the mid to upper 80s. It will be a bit cooler on Sunday, May 27, but still a nice day, with a high temperature in the upper 70s.
We do need to keep an eye on Tropical Storm Alberto which formed off the South Carolina coast on May 19. Current forecast models show the storm eventually moving toward the northeast and weakening by midweek, keeping it away from our area. If the storm moves farther west, it could impact us with some showers or thunderstorms in the middle of the week. For now, we'll stick with the current model trends and keep Alberto away from the Delaware Valley.
Be sure to check in with Phillyweather.net all week long for updates on Tropical Storm Alberto.