For one scientist, climate change in the Northeast announces itself in the abnormal appearances of warm-water fish – an abundance of mahi-mahi and unprecedented sightings in January of Gulf Stream flounder and juvenile black sea bass in shallow waters off the New England coast.
“Nobody had ever seen that before,” said Glen Gawarkiewicz, an oceanographer from the Woods Hole Oceanographic Institution in Massachusetts.
For another scientist, the phenomenon materializes in ocean temperatures, which have been rising for more than a generation, influencing coastal weather and pushing snowfall farther inland.
“Our winters now are not like our winters before,” said Lenny Giuliano, the state meteorologist in Rhode Island.
As water temperatures rise in the Atlantic Ocean and its connected gulfs and bays, the warmth may spread inland and generate temperature variations at the county level.
The water-to-land effect appears along the Great Lakes, which also are warming, said Mark Wysocki, New York state climatologist and a professor at Cornell University.
“There’s a very strong connection,” Wysocki said.
Though the Southwest saw the greatest rise in average air temperatures during the past five decades, data from the National Oceanic and Atmospheric Administration shows the Northeast warmed the most over both longer and shorter time spans.
Nowhere more so than Rhode Island: The state’s average temperature has increased 3.64 degrees compared with its 20th-century norm, according to NOAA records dating back to 1895.
Other states trail closely: New Jersey came in 3.49 degrees warmer; Connecticut, 3.22; Maine, 3.17; Massachusetts, 3.05; and New Hampshire, 2.93.
In the short term, Delaware and New Jersey were tied for the highest increase in average temperature among the lower 48 states, according to NOAA records for a five-year period ending in October. Closely behind were Rhode Island and Connecticut, followed by Arizona, California and Florida.
States could be seeing a “troughing” effect, in which cold air drops from the north and draws warmer air up the coast, said David Robinson, the New Jersey state climatologist at Rutgers University.
Such an effect caused 50 mph wind gusts on Halloween night in New Jersey, Robinson said. He linked it to a tornado in Morris County, about 25 miles west of New York City.