WASHINGTON — The faltering US job market has prompted economists to take a much dimmer view of the country’s growth prospects. That’s a shift from just a few weeks ago, when many were upgrading their forecasts.

Friday’s surprisingly bleak jobs report for May followed a spate of disappointing data. Manufacturing activity slowed, an index of home sales fell and consumer confidence tumbled. Mounting troubles in Europe and elsewhere have heightened economists’ concerns.

JPMorgan Chase sharply reduced its growth forecast for the July-September quarter to a two per cent annual rate, down from three per cent. It cited the weaker US hiring and a likely drop in US exports related to slower growth overseas.

And JPMorgan Chase now forecasts growth of 2.1 per cent for 2012, down from 2.3 per cent.

Julia Coronado, an economist at BNP Paribas in New York, said she now expects growth of 2.2 per cent this year, down from her previous forecast of 2.4 per cent. She also revised down her estimate of growth in the April-June quarter to a 2.2 per cent annual rate, from a 2.5 per cent rate.

Forecasting firm Macroeconomic Advisers and Swiss bank UBS have also marked down their expectations since Friday’s jobs report.

As a general rule, it takes about 2.5 per cent growth to generate enough hiring to keep up with population growth and prevent the unemployment rate from rising. The reduced forecasts suggest that hiring may not strengthen much this year.