* U.S. crude futures extend 2010 intraday peak to $85.22
* North Sea Brent crude oil jumps to over $84 barrel
* Investment inflows seen at start of new quarter
* Coming Up: U.S. non-farm payrolls for March on Friday
By Gene Ramos
NEW YORK, April 1 (Reuters) - Oil prices firmed at 18-month highs on Thursday after upbeat U.S. economic data signaled better oil demand ahead, attracting fund buying as the new quarter began.
A dip in the dollar against the euro and a basket of currencies also prompted buying, traders said.
Ahead of the long holiday weekend and with the key March U.S. jobs report due on Friday, traders were also covering short positions, helping push the market higher for the fourth consecutive session, analysts said.
"This looks like a short-covering rally ... traders don't want to go home with a lot of shorts, knowing the important jobs data will be released on Friday, when the energy markets are closed," said Richard Ilczyszyn, senior market strategist at Lind-Waldock in Chicago.
Short positions are bets that prices will fall.
U.S. crude for May delivery <CLc1> was up $1.14 at $84.90 by 1:45 p.m. EDT (1745 GMT), off the session high of $85.22 a barrel, the highest intraday price since Oct. 9, 2008. The contract settled at $83.76 on Wednesday, its highest close since October 2008.
London ICE Brent <LCOc1> climbed $1.63 to a high of $84.33 before easing a little to trade around $84.
The number of Americans filing new claims for jobless benefits fell last week and factory activity in March hit its highest level in more than 5-1/2 years, bolstering confidence of a continued expansion in the economy. [
]"Upward momentum is very strong," said Eugen Weinberg, head of commodities research at Commerzbank in Frankfurt.
"Money is flowing into commodities at the beginning of the new quarter from all sorts of investors, including funds," he added.
The euro rallied against the dollar, lifted by quarterly positioning as invesetors looked ahead to U.S. nonfarm parolls data on Friday. The dollar also fell against a basket of currencies. [
] <DXY>.JOBS FORECAST
Ahead of Friday's jobs data, the median projection from the 20 economists who have forecast payrolls most accurately over the past year in Reuters' polls predicts 200,000 jobs were created last month.
That is slightly higher than the 190,000 median forecast from the broader sample of 82 analysts in the latest Reuters poll. [
]A rise would mark only the second time payrolls have risen since the recession started in December 2007, although this might be partly due to hiring for the 2010 census.
Oil markets have ignored Wednesday's government report of the ninth consecutive weekly build in U.S. crude stocks, and a surprise, if small, rise in gasoline supplies. [
]U.S. government data showed U.S. crude inventories rose by 2.9 million barrels to 354.2 million barrels last week, Gasoline stocks logged an unexpected 300,000 barrel gain.
"Many are looking at the fact that total implied refined product demand is now in positive territory versus both last year and the five year average for the same week," Dominick Chirichella, senior partner, Energy Management Institute in New York, said in a report.
"SIMMERING TENSIONS"
Simmering geopolitical tensions amid talk of a possible new round of sanctions against Iran, maybe within weeks rather than months, could be underpinning the market, said Edward Meir at brokers MF Global.
But, "with respect to short-term pricing trends, we suspect there might be a temporary pause in the rally," he added.
U.S. front-month crude oil rose 5.5 percent in the first quarter, its fifth consecutive gain. But although it has more than doubled from a December 2008 low, it is still well short of a record high near $150 a barrel hit earlier that year.
After wild swings in the past two years, oil has stabilized recently near the range favored by members of the Organization of the Petroleum Exporting Countries between $70 and $80.
Last quarter, oil peaked at $83.95 a barrel in January to as low as $69.50 in February, a range of less than $15. (Additional reporting by Robert Gibbons in New York, Christopher Johnson in London; Alejandro Barbajosa in Singapore; Editing by Marguerita Choy; Editing by David Gregorio)