The U.S. economy grew by 3.2% in the first quarter of 2019, according to a government release on Friday morning.

The 3.2% rise in gross domestic product was more than twice the 1.5% consensus expected by economic experts in two separate surveys conducted by Blue Chip Financial Forecasts and The Wall Street Journal just three weeks ago.

The growth surprise announced by the Bureau of Economic Analysis on Friday morning immediately set off speculation about whether the strong growth was sustainable and exactly which fundamental factors drove the burst of strength in the government's official first-quarter initial estimate of GDP growth.