LONDON, Nov 27 (Reuters) - London sugar futures dipped on Thursday as rains in major producer Brazil were expected to help development of next year's crop, while cocoa edged up and robusta coffee was little changed.

Trading volumes were thin across soft commodities as it was the U.S. Thanksgiving Day holiday, when U.S. commodity and energy futures and options markets are closed.

London white sugar futures dipped in light volumes as dealers focused on the rains in Brazil and on the start of harvests in Asia.

"I think we're stuck in this range," Michael Liddiard of consultancy Agrilion said.

"The market is focused on the start of harvests in India and Thailand and the weather in Brazil from now until early next year, before the start of the next harvest in the centre-south around April."

London March white sugar ended $4.20 or 1.0 percent lower at $414.50 per tonne. Second month May white sugar was down $4.20 at $425.00 per tonne.

Regarding the second month, Myrto Sokou, senior research analyst with Sucden Financial, said: "Short-term indicators suggest the potential for a retest of the 10-day moving average at $426.09, while support holds near November's low at $409.10."

London cocoa futures firmed, underpinned by expectations for a global deficit.

Commodities trader Olam has forecast a global deficit of more than 120,000 tonnes for 2014/15.

March London cocoa ended 12 pounds or 0.6 percent higher at 1,908 pounds a tonne.

"Short-term indicators suggest the potential for modest gains above 1,900 pounds, while a spike higher could see a retest of the 40-day moving average at 1,927 pounds," Sokou said.

January robusta coffee ended unchanged at $2,096 a tonne as the market remained underpinned by strong demand.