The National Hurricane Center's 7 p.m. CDT Tropical Weather Outlook indicates 1. An area of disturbed weather located a few hundred miles southeast of Bermuda has changed little today. However, environmental conditions are gradually forecast to become more conducive for the development of a low pressure system by late this week when the disturbance is expected to be south or southwest of Bermuda. The system is forecast to move generally northward over the weekend and begin interacting with a frontal system on Sunday, which would limit any additional development. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...medium...50 percent. 2. A vigorous tropical wave is producing a concentrated area of showers and thunderstorms several hundred miles southwest of the Cabo Verde Islands. Environmental conditions are forecast to be somewhat conducive for gradual development of this disturbance over the next few days while it moves westward to west-northwestward at 15 to 20 mph. By the weekend, however, conditions are expected to become less favorable for tropical cyclone formation. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...low...20 percent.