* U.S. Q4 GDP growth 2.1 percent in final estimate
* Yield rise seen temporary (Adds comment, details, byline, updates prices)
By Gertrude Chavez-Dreyfuss
NEW YORK, March 30 (Reuters) - U.S. Treasury debt yields drifted higher on Thursday after data showed the final U.S. gross domestic product number for the fourth quarter was revised higher, reflecting a fairly steady growth path for the world's largest economy.
Yields though have trended lower over the last two weeks, with that of benchmark U.S. 10-year notes declining nearly 30 basis points since hitting a three-month peak on March 14. Analysts said the slight gain in yields, which move inversely to prices, could well be temporary.
"We had decent data so we have a bearish tone in the market," said Stan Sun, interest rates strategist at Nomura in New York. "Not to forget that yesterday we had a pretty good rally and so we're just kind of retracing from there."
The final U.S. GDP growth number was 2.1 percent in the fourth quarter, higher than the second estimate of 1.9 percent growth and exceeding market forecasts for a 2.0 percent rise. The fourth quarter number, however, was lower than that of the third when GDP rose 3.5 percent.
"The trend in growth has remained close to 2 percent, which is weak by past standards, but strong enough in the current cycle to bring down the unemployment rate," said Jim O'Sullivan, chief U.S. economist at High Frequency Economics in Valhalla, New York.
In mid-morning trading, benchmark 10-year notes were down 2/32 in price to yield 2.394 percent, compared with 2.387 percent late on Wednesday.
U.S. 30-year bond prices fell 11/32, yielding 3.011 percent US30-YT=RR, up from Wednesday's 2.994 percent.
On the front end of the curve, U.S. two-year note yields were at 1.277 percent, down slightly from 1.278 percent on Wednesday.
Prior to the release of the data, Treasury prices had a modestly positive tone, in line with gains in European bonds as the European Central Bank was keen to reassure investors that its easy monetary policy is far from ending.
Treasuries have been bid the last two weeks after the Federal Reserve at its last policy meeting stuck to its forecast for a hiking pace of three interest rate increases this year.
More recently, growing doubts about the Trump administration's ability to get anything done to bolster the economy have also pushed Treasury prices higher. (Reporting by Gertrude Chavez-Dreyfuss; Editing by Andrea Ricci)