Blizzard conditions confirmed in Massachusetts

(WHDH) — The National Weather Service says blizzard conditions have been confirmed in Boston, Hyannis, Falmouth and Plymouth.

The weather service defines a blizzard as three or more hours of sustained wind or frequent gusts to 35 mph or greater; and falling or blowing snow that reduces visibility frequently to less than one-quarter of a mile.

Parts of Southeastern Massachusetts are supposed to see 20 inches of snow.