Cotton futures advance, score 2nd straight weekly gain

* Expectations of tight U.S. supplies buoy prices

* Volumes heavy on key index fund rolls

* Speculators raise net long position -CFTC data

NEW YORK, Feb 14 (Reuters) - Cotton futures ended higher on Friday, crawling to a second straight weekly gain as expectations of continued strong demand for U.S. supplies offset pressure from the rolling of key commodities index funds.

The most-active May cotton contract on ICE Futures U.S.

CTc2 edged up 0.46 cent, or 0.5 percent, to settle at 89.04 cents a lb and post a second straight weekly gain.

The benchmark second-month contract CTc2 set six-month highs on Wednesday, recovering from a loss at the start of the week on a monthly U.S. Agriculture Department (USDA) report seen as disappointing.

The spot March contract CTc1 closed down 0.05 cent, or 0.06 percent, at 87.55 cents a lb.

ICE Futures U.S. soft agricultural commodity futures and options markets will be closed on Monday, Feb. 17, for the U.S. Presidents Day holiday. News Search ID:nL2N0LJ16X

Heavy spreading and climbing exchange inventories drove the front-month's discount to the second-month contract CT-1=R as low as 1.65 cents a lb, its steepest discount since early December.

ICE stocks ticked up to 248,800 bales, up from 244,800 bales previously and at their highest since July, exchange data compiled by Reuters showed.

Shipment levels of U.S. cotton "were healthy for another week," said a U.S. broker of the support.

"When they stop, that'll be a warning shot ... that there's less appetite to buy cotton at these prices."

U.S. weekly export data showed shipments of previously booked U.S. cotton were above the prior four-week average, reinforcing traders' worries over tight supplies in the world's top exporter. News Search ID:nIGB33C637

Expectations have risen that the USDA will cut its forecast for ending inventories in the United States due to the recent pace of export sales. The government left them unchanged in Monday's monthly supply and demand report. News Search ID:nL2N0LF0X5

Speculators slightly increased a net long position in cotton futures and options in the week ended Feb. 11, U.S. government data showed on Friday.

(Reporting by Chris Prentice; Editing by Jan Paschal)

((christine.prentice@thomsonreuters.com)(+1 646 223 6136)(Reuters Messaging: christine.prentice.thomsonreuters@reuters.net))

Keywords: MARKETS COTTON/