By David Brough and Nigel Hunt

LONDON, Sept 10 (Reuters) - ICE raw sugar futures climbed toa six-month high on Friday, boosted by concerns about dryweather in Brazil, while arabica coffee also advanced.

London cocoa, however, touched a new one-year low, pressuredby expectations of large main crops in West Africa, the world'smain cocoa-growing region.

ICE benchmark October raw sugar rose 0.49 cent or 2.2percent to 22.92 cents a lb at 1500 GMT after earlier setting apeak of 23.00 cents, a six-month high for the benchmark frontmonth.

London October white sugar was up $11.80 or 1.9 percent at$629.50 per tonne.

Worry about the effect of dry weather in Brazil on yieldssupported the sugar market.

"The dryness could impact on the next crop, which is whythere is tension nearby," said Pierre Sebag of London-basedconsultancy Sugar K Ltd.

Sugar prices are also supported by expectations the globalmarket is likely to be in equilibrium rather than surplus in2010/11. Tight stocks and a big line-up of vessels at Brazilianports have added fuel to the rally.

Dealers cautioned, however, there could be a short-termsetback in the near future.

"The market is strong but technically over-bought," wroteNick Penney in a daily market report of Sucden Financial Sugar.

Arabica futures rose, with the benchmark second month movingback towards Wednesday's 13-1/4 year high of $1.9865 per lb.

Second-month December stood 2.6 cents or 1.4 percent higherat $1.9330 per lb and could be set to test the $2 level in thenear future, dealers said.

Arabica futures have rallied since June on fund buying,while tight supplies have also played a role.

ARABICA PREMIUM

The sustained rally has pushed the arabica premium overrobusta over $1.20 per lb, the highest level since 1997.

London's second-month November robusta futures rosemarginally, with upside limited by expectations of a big crop intop producer Vietnam. November robustas were up $1 at $1,592 pertonne.

Cocoa futures on Liffe hit a one-year low on Friday, weighedby improving prospects for the main crop in West Africa."It is based on the supply information we have got. Everyweek that passes you have an improving supply side situation,particularly out of West Africa," one London dealer said."The industry is well covered ... the market should continueto drift lower unless there is some unexpected change of opinionwith regard to the supply side over the next few weeks," thedealer added.

December cocoa on Liffe eased 23 pounds or 1.2 percent to1,853 pounds a tonne after touching 1,846 pounds, a one-year lowfor the benchmark second month.

Dealers said there was little chart-based support above1,750 pounds, adding the market would need to close above 1,950to indicate a reversal in the current downtrend.

December cocoa on ICE fell $52 tp $2,642 a tonne.

Dealers said the market was paying close attention to theforthcoming election in top producer Ivory Coast but it was notyet clear what impact it might have on prices.

Ivory Coast President Laurent Gbagbo signed a decree onThursday validating definitive voter lists in the West Africancountry, one of the last hurdles before long-delayed electionscan take place.

A vote in the world's top cocoa-producing country is slatedfor Oct. 31, but six such dates have been missed before.

* Prices as of 1506 GMT Product Last Change Percent Move End 2009 YtdPercent ICE sugar 23.00 0.57 +2.54 26.95 -14.66 ICE coffee 192.80 2.10 +1.10 137.60 40.12 ICE cocoa 2642.00 -52.00 -1.93 3310.00 -20.18 Liffe sugar 629.80 12.10 +1.96 710.20 -11.32 Liffe coffee 1588.00 -3.00 -0.19 1332.00 19.22 Liffe cocoa 1854.00 -22.00 -1.17 2271.00 -18.36 CRB index 275.65 2.44 +0.89 283.38 -2.73 Crude oil 76.34 2.09 +2.81 79.36 -3.81 Euro/dlr 1.27 0.00 +0.20 1.43 -11.16 * ICE sugar and ICE coffee in cents per lb, ICE cocoa, Liffesugar and Liffe coffee in dollars per tonne. Liffe cocoa inpounds per tonne. (Reporting by David Brough and Nigel Hunt; editing by JaneBaird)