It's 10 p.m.; do you know where your trader is? Chances are, if he or she is a member of the New York Mercantile Exchange, a good place to look is the nearest computer.

In the Nymex vision of the foreseeable future, traders will not only immerse themselves in the quick-paced world of commodity futures by day, flesh pressed against flesh fighting to make trades, but soon will be trading by the cover of night.But Nymex's nocturnal venture in computerized futures and options trading may not be available for another year, analysts say, despite probable approval by the Commodity Futures Trading Commission.

Nymex said, however, that the system it nurtured for nearly two years will be introduced this fall.

This month, the energy and metals exchange will apprise the CFTC of the fact it is seeking the agency's approval as a 24-hour exchange. The CFTC has not set a date for approval.

Nymex hopes that, by getting CFTC's designation as an electronic after-hours center, it will be the first U.S. futures exchange to offer round-the-clock trading in petroleum and petroleum products.

Nymex did not say when, and if, it will add energy contracts like natural gas to the list, but the exchange noted that platinum futures will start after-hours trading.

Today's U.S. futures trading is done almost exclusively through the ''open-outcry" system of public auctioning on regulated exchanges like the New York Merc.

Electronic trading, which does not require a physical location, has been sought after in the United States by the likes of the Chicago Board of Trade and Chicago Mercantile Exchange with their Globex and Arora systems.

Lengthening New York trading hours through Nymex's system, called Access, is important for the exchange because it will make it more competitive with other exchanges already online. Z. Lou Guttman, exchange chairman, said that globalization of world oil markets made it important for Nymex to develop the electronic trading system.

"We have become a global marketplace. We could no longer deny our foreign customers access to our markets during their regular business hours," he said.

Also, Mr. Guttman said, it is essential that all of Nymex's 800 members have the means to immediately react to world events even after regular trading hours.

Others in the trade said the exchange developed Access when discussions with other exchanges on linking Nymex products electronically fell through. A growing segment of the U.S. oil-trading community already trades around the clock, thanks to markets available in London, Tokyo and Singapore.

Access may be in response to foreign market penetration into U.S. futures business, said traders like Warren Tashnek of Shearson Lehman Bros. in Houston.

For whatever the reason, the concept for Access is not new. Mr. Guttman said "we are not dealing with a new market," but "concentrating on products that we have."

R. Patrick Thompson, exchange president, said the exchange has been looking at an electronic system for more than two years. He said the exchange has not set a specific date for launch of the innovative exchange, neither will exchange officials reveal the cost of the system.

However, they do estimate the system will be able to handle trading on as much as 15 million barrels of crude oil a day. That is about 10 percent of the normal volume during normal business hours.

For all of the risk-taking characteristics of futures traders, computerized trading is a giant step many traders are apprehensive about taking. Some U.S. traders already have had positive experiences with computerized trading on the London International Financial Futures Exchange and the Sydney Futures Exchange.

Shearson's Mr. Tashnek said most traders will still prefer to trade the more traditional foreign markets available after New York closes rather than use the more limited option of computerized trading on the Nymex. Plans are for Nymex's Access to operate from 5 p.m. EST to 8 a.m. the following day. Normal hours are from 8:20 a.m. to 3:10 p.m.

A strong feature of the Access system is the relative ease of entering and exiting an overnight market in the United States, which will increase the open interest for Nymex contracts. Open interest, the number of outstanding long and short positions in the market, is a very good barometer of liquidity, a vital ingredient for the trade and speculative participants, analysts said.

Nymex's Mr. Guttman said that the exchange has dropped plans to participate in the CBT/CME/Reuters PLC's Globex trading system when it begins operations later this year. Mr. Guttman said "we have made a commitment to support our own (Access) system, exclusively."

He explained that Nymex has a five-year agreement with American Telephone & Telegraph Co. and Task Management Inc., partners in the Access system, which he says the exchange will uphold.