NEW YORK, Jul. 29 -- Crude prices ended flat on Thursday after choppy trading as a tropical storm hit the Texas coast, shutting down refineries, and concerns about U.S. debt problems continued weighing on the markets.

The U.S. National Hurricane Center said, Tropical Storm Don is over the central Gulf of Mexico as it moves toward southeastern Texas. A tropical storm warning is in effect for the Texas coast. The warning forced refineries to shut down production and evacuate staff.

Besides the storm, less-than-expected jobless claims last week also helped crude prices. According to the Labor Department, U.S. initial jobless claims fell 24,000 below the important level of 400,000, encouraging investors.

But uncertainties about the upcoming U.S. debt limit deadline continued weighing on the markets. Investors remained wary of debt default risks as the House is scheduled to vote on a GOP bill later Thursday.

Light, sweet crude for September delivery settled up 4 cents at 97.44 dollars a barrel on the New York Mercantile Exchange. In London, Brent crude for September delivery edged down 7 cents to close at 117.36 dollars a barrel.