PARIS (Dow Jones)--It's hard to argue OPEC ministers ever deserve much sympathy but ahead of Tuesday's meeting in Vienna some observers may feel a twinge or two.

After all, the six months since OPEC ministers last met have proved a long time for the oil exporting club. Crude oil futures are hovering below record highs as the outlook for OECD economies - and future oil demand - has taken a turn for the worse.

Blame the impact of the U.S. subprime housing-loan crisis on short-term credit markets and U.S. consumption.

Back in March, however, future prices were nearly 25% lower. Yet the outlook for the global economy - and oil demand - was considerably brighter as economic data suggested, and investors believed, the impact of the subprime debacle would be contained.

So OPEC finds itself reassessing production at a possible inflection point in the economic cycle where the chances of misjudging supply and demand look high.

That will test OPEC's ability to keep prices in a range that suits its members without prejudicing importing countries.

In those circumstance, the option of sitting on their hands and waiting to see how things pan out may be hard for ministers to resist, confident they can tweak output behind the scenes if necessary.

Cutting production, in anticipation of slowing U.S. and European growth, risks sending crude oil prices higher, in the immediate future at least.

U.S. stocks have been tightening of late and the hurricane season in the Gulf of Mexico isn't over. It's speculative bets on short-term supply bottlenecks that a bad hurricane season might exaggerate that helps explain today's frothy prices.

But once the hurricane season is over, prices might tumble without speculation to support them particularly if consumption is on the slide as the U.S. economy tips toward recession.

On the other hand, OPEC can't ignore the risk of higher, not lower, demand should the northern hemisphere suffer a cold winter and Asian economic growth continue at its recent rapid pace, independent of the economic headwinds the U.S. and Europe are running into.

Asian growth does look robust. As for guessing how the weather will turn out, there's little OPEC can do. Many of the world's meteorologists are convinced we face persistently warmer winters for decades ahead because of a CO2-charged greenhouse effect, but few dare to forecast the weather three, let alone six, months out.

The futures market complicates OPEC's life too. The crude futures market is backwardation - when futures lose value further out in time - that discourages the holding of crude oil inventory, ensuring most of supply is reaching the market.

But if demand slows more than OPEC has bargained for, the futures market might move back into contango, encouraging oil majors to hold stocks for future delivery, depriving the market of supply. After all, producers like Total have said they won't be producing as much oil as they'd previously thought.

Then there's the chance of future dollar weakness, which a growth-bolstering Fed rate-cut might encourage, reducing the real value of OPEC revenue, as the organization fretted about in July.

So it will be a brave OPEC minister that's going to argue for a shift in the organization's output - one way or another - over the next couple of days.

(Matthew Curtin has been a financial news reporter since 1990 and has written on international finance and business for Dow Jones Newswires - from South Africa, Singapore and France - since 1994. He can be reached at +331 4017 1746 or by e-mail: matthew.curtin@dowjones.com)

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