* Tropical storm possibility boosts oil futures
* U.S. Q1 economic growth revised down
* Coming Up: Group of 20 meeting at the weekend (Recasts, updates prices, market activity; new bylines, moves dateline from previous LONDON)
By Robert Gibbons and Gene Ramos
NEW YORK, June 25 (Reuters) - Oil surged more than 2 percent on Friday on concerns that a tropical disturbance in the Caribbean Sea may develop into a storm and threaten Gulf of Mexico production.
At 12:58 p.m. EDT (1658 GMT), U.S. crude futures <CLc1> were up $2.12, or 2.7 percent, at $78.63 a barrel, having traded as high as $78.92, which matched Monday's intraday high. Crude had bounced from a session low of $75.90.
ICE Brent crude futures <LCOc1> were up $1.52, or 1.99 percent, at $77.99, off a $78.32 high.
Trading sources said buy stop orders were triggered when crude moved back toward $79 and that U.S. gasoline futures also rose sharply.
Crude futures trading volume on the New York Mercantile Exchange from 11:50 to 11:55 a.m. EDT (1550-1555 GMT), when crude oil prices moved sharply higher, increased more than four times from the previous five-minute period, according to Reuters data.
"RBOB (gasoline futures) strength could be a jump start to the usual pre-July 4th buying," said Michael Guido, associate director/hedge fund coverage at Macquarie Bank in New York.
"If this storm does become a threat, then the usual pre-holiday buy programs for gasoline will become much more expensive, hence the prompting people to act today, with shorts getting caught up in the mix," Guido added.
U.S. July gasoline futures were up 6.05 cents at $2.1540 a gallon.
A low-pressure area over the western Caribbean Sea now has a high 70 percent chance of developing into a tropical depression over the next 48 hours, the U.S. National Hurricane Center said on Friday. [
]Some weather models project the system will cross Mexico's Yucatan Peninsula over the next few days before entering the central Gulf of Mexico, threatening BP Plc <BP.L> efforts to clean up its oil spill.
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For graphics U.S. Gulf of Mexico offshore crude output:
http://link.reuters.com/bax24m
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"The greatest risk will be with the potential development of a tropical storm that could make its way to the Gulf of Mexico," said Olivier Jakob with Petrometrix.
U.S. crude oil and product inventories remain much higher than year-ago levels. [
] The high inventory levels might cushion any price spikes that might result from weather-related supply disruptions. Prices jumped when hurricanes Katrina and Rita hit the U.S. Gulf of Mexico in 2005.Support for crude also came from the weakening of the dollar index <.DXY>, measuring the greenback's strength against a basket of currencies and the euro's <EUR=> recovery against the dollar after midday in New York.
U.S. consumer sentiment rose in June to its highest since January 2008, while reports of job losses were down sharply from a year ago, according to the Thomson Reuters/University of Michigan's Surveys of Consumers. [
]Earlier in the session, crude oil's gains were tempered by data showing slower-than-expected economic first-quarter growth in the United States and worries about the fragility of global recovery ahead of a weekend summit of Group of 20 nations.
U.S crude oil is expected to average $79.86 a barrel in 2010, a Reuters poll showed, a slight drop from May's survey and the second consecutive lower monthly forecast after more than a year of rising expectations. [
]Front-month U.S. crude futures' $64.24 intraday low on May 20 was the weakest front-month price since $62.76 was struck on July 30, 2009. Prices recovered to a 2010 peak of $87.15 on May 3, but fell back. (Additional reporting by Rebekah Kebede in New York, Ikuko Kurahone in London, Alejandro Barbajosa in Singapore; Editing by David Gregorio)