NEW YORK/LONDON, Aug 4 (Reuters) - Raw sugar futures steadied on Monday after surging 5.6 percent in the first three minutes of trade in a knee-jerk reaction to a sugar warehouse fire at top grower Brazil's Santos port. Cocoa turned lower after rising to three-year highs.

Arabica coffee on ICE Futures U.S. and robusta coffee on Liffe sank more than 3 percent on a wave of chart-based selling.

Sugar prices skyrocketed after news that a fire at a warehouse operated by producer Cosan SA destroyed 15,000 tonnes of the sweetener. It was the second in the past year at the port following a fire at Copersucar SA's sugar export terminal in October.

"It may add some pressure in the short term to the logistics/outloading situation although recent shipping stats suggest a lack of urgency in shipments from CS Brazil, in any case," Green Pool Commodities said in a note.

Benchmark ICE October raw sugar futures dipped 0.03 cent, or 0.2 percent, to close at 16.32 cents a lb. More than one-fifth of the contract's volume was dealt in the first three minutes of trade, when the price soared to the session high at 17.26 cents, the highest since July 24.

October whites on Liffe slipped $1, or 0.2 percent, to settle at $434.70 a tonne.

COCOA HIGH

In cocoa, fund buying helped benchmark ICE September futures hit a three-year high of $3,239 per tonne before the contract turned lower to close down $12, or 0.4 percent, at $3,195 a tonne in heavy volume.

"It's purely fund buying," a London-based broker said, referring to the market's earlier strength.

The market turned lower as the buying faded.

Liffe December cocoa futures closed down 1 pound, or 0.05 percent, at 1,987 pounds per tonne, after rising to 2,011 pounds, the highest since July 2011.

Coffee futures fell sharply as a wave of chart-based selling took prices below their 100-day moving averages on both the ICE and Liffe markets, traders said.

ICE September arabicas settled down 1.85 cents, or 1 percent, at $1.9050 per lb, after falling 4.7 percent to $1.8330.

The market remains volatile on persistent uncertainty over the size of top grower Brazil's crop following a drought in January and February.

"We maintain our forecast of Brazilian production for the 2014/15 season at 47.5 million bags and highlight that while production forecasts remain wide, the next month will be a telling period as more accurate counting is completed," Rabobank said in a commodities note.

Rabobank's three-month price forecast was revised up by 10 cents per lb to $1.85.

November robusta coffee futures on Liffe finished down $85, or 4.1 percent, at $2,008 per tonne. (Additional reporting by David Brough in London; Editing by David Clarke, Jane Merriman, Tom Brown and Jan Paschal)