(Rewrites throughout, updates prices; adds comment, NEW YORK dateline)
NEW YORK/LONDON, March 13 (Reuters) - Raw sugar futures tumbled to an 8-1/2-month low on Tuesday, on chart-based selling after failing to rise above 13 cents per lb for the third straight session, while London cocoa turned lower after tapping a 13-month high.
* May raw sugar settled down 0.31 cent, or 2.4 percent, at 12.62 cents per lb, after falling to 12.53 cents, matching two consecutive session lows reached in June.
* Chart-based selling pressured prices after the spot contract again failed to breach the psychological level of 13 cents, traders said.
* Light short covering by speculators on Monday dried up and producer hedging resumed, dealers said.
* May white sugar settled down $5.70, or 1.6 percent, at $353.70 per tonne.
* The front month remained at a premium to the second position, suggesting potentially tighter nearby supply despite a large surplus expected this year, though it narrowed to $4.10 from Monday’s peak at $6.40.
* “We are not quite there yet and activity in Brazil has been adding some support,” INTL FCStone said in a market update. “However, healthy supply in Thailand, India and Europe will offset this when supply reaches the market.”
* May London cocoa settled down 15 pounds, or 0.8 percent, at 1,776 pounds per tonne, after hitting 1,802, its highest since January 2017.
* May New York cocoa settled down $14, or 0.6 percent, at $2,532 per tonne, inching away from Monday’s 16-month high of $2,558.
* New York cocoa has rallied more than 30 percent in 2018 so far, sharply outperforming other core U.S. commodities on signs of improving demand and forecasts for a smaller global surplus.
* May arabica coffee settled up 2.1 cent, or 1.8 percent, at $1.2155 per lb, on speculative short covering.
* The market was boosted by the firm Brazilian real versus the U.S. dollar, dealers said. Brazil is the world’s biggest coffee grower.
* Despite the modest rise, this was the benchmark contract’s strongest session in five weeks as prices have remained near February’s 2-1/2-month low of $1.1855 as participants monitored rain in Brazil, which one dealer said was beneficial.
* May robusta coffee settled down $6, or 0.3 percent, at $1,763 per tonne.
* The March contract remained at a sizeable premium to May LRCH8-K8 after peaking at $59 two weeks ago, which dealers said signaled tighter supplies available for delivery against the futures market, as most shipments of fresh coffee from Vietnam had gone directly to coffee roasters.
Reporting by Marcy Nicholson in New York and Ana Ionova in London Editing by Susan Fenton and Susan Thomas