Hi Megan,

A blocking high pressure refers to an area of higher than normal atmospheric pressure that acts like a big mountain in the atmosphere. It blocks storms from going through and instead slows down the storms as they try to find their way around.

As for why the northeast keeps getting hit by Nor'Easters, the atmosphere has been stuck in a pretty consistent pattern over the last several weeks which is consistent with a bunch of nor'easters moving up the east coast. Once that pattern breaks, the onslaught of storms will too.

And lastly, Atmospheric Rivers are narrow streams of moisture flowing directly from the humid tropics. The West Coast relies on these events for around half of their precipitation during the winter wet season.