Forecasters predict ocean effect snow Tuesday

Low pressure colliding with an Arctic air mass will produce four to eight inches of ocean effect snow on Martha’s Vineyard beginning Tuesday afternoon, according to National Weather Service forecasters.

The weather service issued a winter storm watch Monday, for the period from Tuesday afternoon through Wednesday morning.

“Low pressure developing well south of New England during Tuesday will combine with Arctic air moving across the region to cause ocean effect snows,” forecasters wrote in the advisory. “Temperatures will be very cold, ranging from the teens across the interior to around the mid-20s across outer Cape Cod. This will mean that the snow will pile up rather quickly, especially along south coastal areas.”

The predicted snow will not come from a traditional storm, but from the effect of very cold air flowing across the relatively warmer ocean waters, producing snow along the coastline. The weather phenomenon is more common near the Great Lakes, where the prevailing northeast winds often produce lake effect snow.

Forecasters predict winds will average 15 to 20 miles per hour, with gusts up to 35 miles per hour, causing reduced visibility because of blowing snow. The weather service expects clearing by Thursday, but temperatures will remain very cold.