At least 20 states are under a frost or freeze guard, warning or advisory Saturday morning. Although most of these states are in the Midwest or Northeast, the advisers extend all the way to Georgia and South Carolina.
In some northeastern states, it will feel more like the beginning of March than May. A system that began in the Great Lakes region will bring gusty winds and 6 to 12 inches of wet snow to New England.
"It looks like inland New England will see significant amounts of wet snow with northern winds getting stronger and gusty late Friday night through Saturday morning," said the Weather Prediction Center.
For cities like New York, Albany and Hartford, cold rain will be the main focus, but some snow can be blended.
Blame the polar vortex
These winds tend to keep the bitter cold air locked in the Arctic regions of the northern hemisphere. Sometimes the vortex may be distorted and dip further south, allowing cold air to spill south.
But it didn't spill out in the US this winter. That is why spring and winter have been mild and large east coast towns have such low snowfall.
Now, the polar vortex is weakening, allowing Arctic air to spill – leading to falling temperatures in the east this weekend.