Economists upgraded their growth estimates for U.S. real gross domestic product, according to the latest Survey of Professional Forecasters released today by the Federal Reserve Bank of Philadelphia. But they estimate unemployment will reach 9.9% in the fourth quarter, and remain there until the first quarter when they say the U.S. will again add jobs.

Economists in the survey estimated real GDP growth of 2.4% for the third quarter of this year, up from the previous estimate of only 0.4% growth.

For full year 2009, real GDP will still fall by 2.6%, according to the economists. Real GDP should post 2.3% growth for full year 2010.

The U.S. unemployment rate will reach 9.9% in the fourth quarter, up from a previous estimate of 9.8%. Unemployment won't head down again until the second quarter of 2010, according to the report.

Economists in the report estimated an annual average unemployment rate of 9.2% for 2009 and an average unemployment rate of 9.6% for 2010. The jobless rate should go down to an 8.9% average annual rate in 2011.

The U.S. will lose an estimated 273,100 jobs per month in the third quarter, going down to 81,000 jobs lost per month in the fourth. Economists estimated job gains will return in the first quarter with increases of 51,500 per month.