COMMODITIES-Up for 2nd week; cotton near year-high, natgas jumps

* CRB commodities index posts second weekly gain

* Cotton up 23 pct on year, prices at late March 2012 high

* Natgas rises 25 pct from five-week low hit in February

NEW YORK, March 15 (Reuters) - Cotton prices neared a one-year peak on Friday as merchants and speculators kept bidding up the fiber a day after data showed a spike in U.S. weekly exports, and natural gas rallied on cold weather, leading commodities higher. Oil prices rose as supportive U.S. economic data fueled prospects of increased demand in the world's top oil consumer, amid concerns over Middle East supplies. Copper fell from rising stockpiles of the metal in top buyer China. Gold inched up as the dollar slid against other major currencies. In agricultural markets, raw sugar rose while arabica coffee dropped to a 33-month low and soybeans fell for a fourth straight day. The Thomson Reuters-Jefferies CRB index, a global benchmark for commodity prices, rose marginally, ending up for a second week in a row. Gasoline and heating oil helped the CRB's rise, along with cotton and natural gas.

CHINA FUELS COTTON RALLY Cotton's continuous front-month contract in New York, May , settled up 1.64 cents, or 1.8 percent, at 92.50 cents a lb. It peaked at 93.93 cents during the session, touching a high from late March 2012. After sliding for two years, the front-month cotton contract has jumped 23 percent so far in 2013. Physical buying has supported the run-up, although short-covering has contributed too, with merchants becoming buyers as well. While speculators boosted their net long position in cotton futures and options to highs not seen since September 2010, commercial dealers have also boosted their net short position. The size of the short position has made the market prone to short-covering rallies as merchants sought to cover their bets. Another factor for the U.S. cotton rally is China. While the U.S. Department of Agriculture has forecast a record global surplus by the end of July, more than half of those reserves are expected to be held within China's stockpiles, unavailable to the global marketplace. China began building its stocks in 2011, paying above global prices to support farmers. The world's largest cotton consumer is forecast to have enough fiber in its stocks by the end of July to meet demand for more than a year. "Cotton is benefiting from several factors. China cotton buying is the most direct factor," said John Flanagan, trader at Flanagan Trading Corp in Fuquay-Varina, North Carolina.

COLD WEATHER DRIVES NATGAS Natural gas hit a 3-1/2-month high on supportive U.S. weekly storage data and forecasts for more cold weather in consuming regions next week. Above-average nuclear power plant outages also helped keep momentum to the upside. In New York, the front-month natural gas contract, April , settled up 1.6 percent at $3.872 per million British thermal units. The contract rose to as high as $3.924 mmBtu in electronic trade, a peak since late November, according to Reuters data. Traders said the chart picture for gas looked supportive after the front-month contract broke through several key resistance levels on its 25 percent run-up from a five-week low of $3.125 per mmBtu, hit in mid-February. But some cautioned that the impending end of winter could provide resistance to higher prices. "The natural gas market extended recent gains with apparent ease as the temperature outlook trended cooler again. As we've been noting, however, the market is in full weather-driven mode here and is only as strong as the underlying forecast, and will see a downside test once the weather pattern changes," said Citi Futures energy specialist Tim Evans.

Prices at 3:12 p.m. EDT (1712 GMT)

LAST/ NET PCT YTD CLOSE CHG CHG CHG US crude 93.52 0.49 0.5% 1.9% Brent crude 110.07 1.11 1.0% -0.9% Natural gas 3.872 0.060 1.6% 15.5%US gold 1592.60 1.90 0.1% -5.0% Gold 1591.70 1.90 0.1% -4.9% US Copper 350.80 -1.55 -0.4% -4.0% LME Copper 7752.00 -48.00 -0.6% -2.3% Dollar 82.231 -0.375 -0.5% 7.1%US corn 717.00 0.50 0.1% 2.7% US soybeans 1426.00 -9.50 -0.7% 0.5% US wheat 723.00 -1.75 -0.2% -7.1%US Coffee 137.50 -2.15 -1.5% -4.4% US Cocoa 2115.00 -15.00 -0.7% -5.4% US Sugar 18.89 0.05 0.3% -3.2%US silver 28.851 0.044 0.2% -4.6% US platinum 1592.40 2.60 0.2% 3.5% US palladium 775.65 4.90 0.6% 10.3%