UPDATE 2-Oil faces 3rd down week on U.S. demand doubts

                                
 * Likely weaker U.S. GDP pressures oil prices
                                
 * Fed Chairman Bernanke's speech in Wyoming awaited
                                
 * Coming Up: Revised U.S. GDP 2nd quarter; 1230 GMT
 
                                
 (Recasts, updates prices, previous SINGAPORE)
                                
 By Joe Brock
                                
 LONDON, Aug 27 (Reuters) - Oil fell towards $73 a barrel on
Friday, snapping a two-day rally and heading for a third
straight week of losses on lingering doubts over the outlook for
U.S. oil demand.
                                
 The U.S. government is expected to revise second-quarter
gross domestic product growth lower on Friday to an annual pace
of 1.4 percent from 2.4 percent, a Reuters survey shows, in
another signal of lacklustre economic recovery in the world's
biggest fuel consumer.
                                
 Friday's negative sentiment eclipsed a positive U.S. jobs
report in the previous session, which helped boost front-month
U.S. crude by almost 1.2 percent on Thursday.
                                
 U.S. crude for delivery in October <Wc1> fell 17 cents to
$73.19 a barrel by 0744 GMT, after touching an intraday trough
of $70.76 on Wednesday, the lowest price since early June.
Prices have slid about $10 from a peak near $83 on Aug. 4.
                                
 October ICE Brent <LCOc1> slid 10 cents to $74.92.
                                
 "The fundamental picture is very negative," said Jonathan
Barratt, managing director at Commodity Broking Services in
Sydney.
                                
 "If you get supportive data in terms of GDP and stimulus,
prices could go to the top of the trading range, but if it comes
lower than expected, the environment is so negative that we
could see a break of $70."
                                
 Although new U.S. jobless claims fell more than expected
last week, they were too high to signal a shift in a weak labour
market that is constraining economic growth. [ID:nN26186848] 
                                
 
                                
 GROWTH CONCERNS
                                
 Later on Friday in a speech to fellow central bankers, U.S.
Federal Reserve Chairman Ben Bernanke is likely to discuss the
uncertain prospects for the economy, but is not expected to give
many clues about whether the central bank will pump more cash
into the economy to keep the recovery going. [ID:nN2485884]
                                
 Weakness in the consumer sector has slowed energy demand
growth in the U.S, sending the nation's total petroleum
inventories to their highest since weekly records began in 1990.
                                
 Bloating U.S. inventories are depressing prices of U.S.
benchmark West Texas Intermediate crude relative to North Sea
Brent. The premium of front-month Brent futures over front-month
WTI jumped to as high as $1.80 on Thursday, the widest since
early June, receding to about $1.65 on Friday.
                                
 Front-month U.S. crude is also trading at discounts to
contracts for the following months, a market structure known as
contango.
                                
 For a graphic: http://link.reuters.com/nuj57n
                                
 Tropical Storm Earl in the eastern Atlantic Ocean continued
to move westward on Thursday, with the U.S. National Hurricane
Center still expecting the system to become the season's third
hurricane by Saturday. [ID:nN26197778]
                                
 Early computer models still show the storm moving west and
the northwest, away from key oil and gas producing areas in the
Gulf of Mexico. Hurricane Danielle, which strengthened to
Category 3, was also expected to stay in the Atlantic.
[ID:nN27204258]
 (Additional reporting by Alejandro Barbajosa in Singapore;
editing by Keiron Henderson)