We have been talking a lot about the weak housing market lately, and this morning we get another sign of just how bad things are with luxury home builder Toll Brothers (NYSE: TOL) warning it will see a huge decrease in its quarterly revenues.

The Pennsylvania-based home builder has not yet released official numbers, but will be hosting a quarterly outlook conference call today at 2:00 PM EDT about the fiscal third quarter ended July 31.

The company, which reports earnings August 22, expects revenue to fall 21 percent to about $1.21 billion based on preliminary estimates. Toll also said it wasn't comfortable giving earnings guidance.

This can't be a good sign.

Not only is the company preparing investors for a weak fiscal third quarter, it also is setting the stage for more weakness in future quarters. In this morning's announcement, Chief Executive Robert Toll said that uncertainties in the mortgage market right now could continue to lower the pace of home sales moving forward.

Surprisingly, the stock is trading higher in pre-market trading, but I would not be surprised to see this reverse once the market opens up and Wall Street's big boys get into the action.

Michael Fowlkes has worked as a stock trader for seven years and spent the last two years working as an analyst for the online investment advisory service Investor's Observer.