First came the “polar vortex” — now it’s the “pollen vortex.”

Forced to lie dormant by the long, brutal winter, trees are now set to start reproducing like crazy — and create a massive amount of pollen that could wallop your sinuses this weekend.

Pollen count in the Northeast will soar to “high levels” Saturday and Sunday, when warm temperatures will prompt plants to create the sniffle-inducing substance, reports Pollen.com, which offers allergy “forecasts.”

In New York City, where the temps could hit 70 degrees Saturday, allergy symptoms will “become more severe,” the site says.

April is generally the worst month of allergy season, but the pollen count this month has so far been the lowest in the past decade, likely due to chilly temperatures, the online magazine Slate reported.

Pollen levels will drop to “medium-high” by Tuesday, Pollen.com predicts.

“DC tree pollen spiking . . . count is 412 grains/cubic meter . . . almost double yesterday’s level,” Capital Weather Gang, which tracks Washington, DC, weather, tweeted Friday.