Unusually cold water has appeared along the United State’s Atlantic coast this summer, chilling swimmers and bringing fish that don’t usually appear until the onset of fall. Thermometers in the surf near Nags Head, North Carolina, show a temperature of 60 degrees Farenheit—it’s typically close to 80 at the end of July. There are a handful of theories to explain the strange conditions: winds are blowing warm surface waters out to sea, forcing cold water from the ocean depths to upwell along the coast; a current is carrying cold water from the north; increased stream runoff from the summer’s high rainfall is cooling the ocean surface; or the absence of warm-water eddies which normally spin off from the Gulf Stream. NOAA scientists are currently studying data from satellites and ocean buoys, hoping to find an explanation, while many beachgoers sunbathe instead of swimming.
This image from Moderate Resolution Imaging Spectroradiometer (MODIS) data shows the current water temperature (July 20, 2003) compared to an average July. Blue areas are colder than normal, while red regions are warmer.
Image by Jesse Allen, Earth Observatory, NASA GSFC