After a quiet but brief dry weather period in portions of the Mid Atlantic the last two days, a new potent storm is expected to arrive and bring with it very heavy rain. While showers and storms will move into portions of the Mid Atlantic later today, the best chance of heavy rainfall will be from Friday afternoon through to Saturday afternoon. The heaviest rain is expected over New Jersey, Pennsylvania, Maryland, and Delaware.
Areas that were impacted by heavy rainfall earlier this week will be particularly vulnerable to another round of flash flooding. Additionally, a few thunderstorms may become severe with
the primary threat being damaging winds. It now appears this system will move a bit slower than originally thought; rather than clearing out for early Saturday morning, clouds and showers may linger for a good part of the day, especially along the coast.
Overall, total rainfall when all is done will be around 1-2″ over northern New Jersey and the Lehigh Valley of Pennsylvania, 2-3″ inches over the Delaware Valley and southern New Jersey, and 3-3.5″ inches over the DelMarVa region. Beyond these healthy amounts, thunderstorms may bring locally higher totals to some areas; amounts over 4″ are possible in this region. Because of this heavy rain threat, the National Weather Service office responsible for the Philadelphia metro area says, “eventually, flood watches may be issued for parts of the region, so pay attention to future forecasts.”
With abundant clouds and heavy precipitation, temperatures will be mostly below normal Friday and into the weekend.