Harvey will cost the equivalent of 1 percent of the nation’s GDP — about $190 billion — and every American will be feeling the pinch at least through the end of the year, an ­expert said Friday.

The catastrophe “is just beginning in certain areas, said AccuWeather President and Chairman Joel Myers, in revising his original $160 billion cost upward.

“This is the costliest and worst natural disaster in American history,” he said.

Myers said the storm’s cost is equal to those of Hurricanes Katrina and Sandy combined.