If you're at the beach, I'm sure you're aware of the level of chill that's in place in the water in many Shore towns as ocean temperatures in the 50's and 60's are common along the South and even Central Jersey coastlines. This is also an issue down into Delaware, Maryland, and the Virginia Capes, although not to the level of extreme that the Jersey Shore is dealing with.
Upwelling, the process of colder water being pulled to the surface while warmer water pushes away, has been at work for much of the summer thanks to a persistent southwest and southerly flow along the coastline over the past four weeks, parallel to the coastline. This scenario provides a path for warmer water to escape and cooler water to bubble to the surface...which is why the Shore has been as chilly as it has been in some locations.
The localized chill in the water at the Shore is the exception, not the rule, in terms of the Atlantic. Much of the Atlantic is running warmer than average this year, some places by as much as two or three degrees Fahrenheit. There are pockets of "cooler" water out there -- particularly just north of the Caribbean islands as well as near Florida -- but the waters around Bermuda and to the Carolinas are running pretty warm for this time of the year.
The upwelling issue will subside somewhat when the mean wind flow at the surface shifts more to an onshore flow (easterly wind of some sort) for a couple of days. This will help ease the persistent upwelling along the coast and help warm that water up at the immediate coastline. It may take a few days to get those water temperatures warmed up if such a regime change takes place in the wind. There are some indications that with the cool frontal boundary passage tomorrow night winds may nudge in that direction at the Shore. This should help ease the upwelling and begin to push warmer water back towards the coast.