* Spot raw sugar spread premium shrinks
* Cocoa trade focused on next week's grind data
* Latest Brazil coffee crop forecast viewed as bullish (Recasts, updates trading, adds comments, byline, NEW YORK dateline)
By Marcy Nicholson and David Brough
NEW YORK/LONDON, April 9 (Reuters) - Raw sugar and cocoa futures dipped under pressure from a stronger dollar on Thursday, while arabica coffee defied the session's weak trend and rose on a crop forecast for top grower Brazil that was viewed as bullish.
Volume was heavy in all ICE Futures U.S. soft commodities on the second day of the index roll, which buoyed May/July spread activity.
Raw sugar futures fell on currency pressure as the U.S. dollar rallied more than 1 percent. The May/July spread SB-1=R initially extended gains and rose to a 0.14-cent premium, the highest since Feb. 27, but then turned lower as market participants holding short positions rolled into the July contract, traders said.
May raw sugar futures on ICE closed down 0.17 cent, or 1.3 percent, at 12.80 cents a lb.
"A lot of short covering happened yesterday so there is a lack of buying today," said Nick Gentile, managing partner of commodity trading advisor NickJen Capital in New York.
May white sugar ended down $2.80, or 0.8 percent, at $363.60 per tonne.
New York cocoa edged lower as the sterling fell against the U.S. dollar. Talk that Ghana may have re-entered the market to forward sell also added pressure, traders said.
"Most of the weakness in cocoa is dollar-driven," a senior cocoa trade source said.
The source said the cocoa market was also focused on expectations for weak European and North American grind data, a measure of demand, due next week.
New York May cocoa finished down $15, or 0.5 percent, at $2,792 a tonne, while London May cocoa inched up 3 pounds, or 0.2 percent, to close at 1,947 pounds a tonne.
Arabica futures were buoyed by a forecast by U.S. coffee importer Wolthers Douque pegging Brazil's 2015/16 coffee crop at 45.6 million bags, at the low end of trade house estimates.
"The algos that trade the news bought off of that story," Gentile said.
May arabica settled up 1.75 cents, or 1.3 percent, at $1.3745 per lb. London May robusta coffee futures ended up $1, or 0.1 percent, at $1,791 per tonne. (Editing by Keith Weir and Bernadette Baum)