NEW YORK, Aug 16 (Reuters) - Cotton futures touched a five-month high on Friday as expectations of continued unfavorable weather in key growing regions of the United States fueled concern over supplies in the world's top exporter.

The benchmark December cotton contract on ICE Futures U.S. was up 1.62 cents, or 1.8 percent, at 93.41 cents per lb at 10:54 a.m. EDT (1454 GMT) after rallying to 93.72 cents a lb, the second month's highest level since mid-March.

"We're seeing too much moisture in the Southeast and we already have short cotton acres planted. That's moving us into a new range," said Sterling Smith, a futures specialist at Citigroup in Chicago.

The U.S. Department of Agriculture lowered its forecast for U.S. output in the 2013/14 crop year that began on Aug. 1 on Monday, citing reduced yields in the key growing region. The U.S. crop is expected to be the smallest in four years.

That fueled a rally that began last week on a technical "break-out" as cotton's chart turned bullish, dealers said.

Market open interest has surged in recent days, signaling renewed speculator interest, dealers said.

Investment from noncommercial dealers helped drive front-month prices in mid-March to about 94 cents a lb, the highest level in a year. (Reporting by Chris Prentice; Editing by John Wallace and Peter Galloway)