NEW YORK (Reuters) - The U.S. economy is on course to expand 0.9 percent in the second quarter, a forecast model from the Atlanta Federal Reserve showed on Thursday, after the government's estimate on first-quarter growth came in at a paltry 0.2 percent.

The Atlanta Fed's GDPNow program had projected gross domestic product likely grew 0.1 percent in the first three months of the year.

The forecast model has attracted market attention in the past 24 hours due to its accuracy. The median forecast among analysts polled by Reuters was a 1.0 percent rise in first-quarter growth.

Thursday's GDPNow reading was the first one for the second quarter. It will change with the 13 sets of data that make up the government's calculation of its initial or "advance" GDP reading.

"As more monthly source data becomes available, the GDPNow forecast for a particular quarter evolves and generally becomes more accurate," the Atlanta Fed said on its website.

GDPNow is updated five or six times a month with at least one following six data releases: manufacturing activity data from the Institute for Supply Management; the trade balance; retail sales; residential construction; advance report on durable goods and personal income and spending.

Other data the model incorporates include wholesale trade and existing home sales.

(Reporting by Richard Leong; Editing by Chizu Nomiyama)