* White sugar premiums fall from contract highs
* NY cocoa sees weakest week in nearly a year
* Arabica closes the week down 6.1 percent
* Coming up: U.S. Commitments of Traders report at 2030 GMT (Rewrites throughout, updates prices; adds comment, second byline, NEW YORK dateline)
By Marcy Nicholson and David Brough
NEW YORK/LONDON, Jan 8 (Reuters) - Sugar futures on ICE turned lower on Friday, giving back gains from the prior session's rally and taking the white premium off contract highs as traders focused on index reweighting, while coffee and cocoa rose for the first time this week.
After four days lower amid turmoil in Chinese financial markets, several larger markets recovered losses. The 19-market Thomson Reuters CoreCommodity Index inched up above the prior session's 13-1/2-year low despite a stronger U.S. dollar.
March raw sugar settled down 0.29 cent, or 2 percent, at 14.46 cents per lb in heavy volume. This was in stark contrast to the prior session's 2.3 percent jump on nearby demand for white sugar.
Traders said that index reweighting began and that indexes are widely expected to sell a large amount of sugar futures contracts through Thursday.
March white sugar settled down $9.1, or 2.1 percent, at $419.70 per tonne, having jumped on Thursday to the highest since November 2014 at $432.70.
The surprise turn lower took the March/May white sugar spread LSUH6-K6 below a contract high of $12.80 reached on Thursday, when the whites-over-raws premium also rose to a contract high above $103. The spreads rallied on concerns about nearby supplies of white sugar, which in turn buoyed expectations for a rise in raw sugar demand.
Nick Penney, senior trader at Sucden Financial Sugar, said he expects a slight fall in the net long position held by speculators in the next U.S. Commitments of Traders report due after the market closed.
March arabica settled up 0.55 cent, or 0.5 percent, at $1.19 per lb. Having fallen four out of five days this week, the spot contract finished the week down 6.1 percent, its biggest fall since late August.
March robusta settled up $6, or 0.4 percent, at $1,485 per tonne.
Upside in robusta prices was limited by ample output from top grower Vietnam as its harvest wrapped up.
New York cocoa rose for the first time in six sessions and after falling to an eight-month low at $2,898 per tonne on Thursday on speculative selling.
March New York cocoa settled up $54, or 1.8 percent, at $3,017 per tonne, but closed the week down 6 percent, the biggest weekly fall since late January 2015.
London March cocoa settled up 48 pounds, or 2.3 percent, at 2,155 pounds per tonne, having hit a four-month low of 2,060 pounds the previous day. (Editing by David Goodman and Meredith Mazzilli)