For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Central Tropical Atlantic: A broad area of low pressure over the central tropical Atlantic is producing a large area of disorganized cloudiness and showers. Although environmental conditions ahead of the system are currently only marginal favorable, some gradual development of this system is expected over the next several days and a tropical depression is likely to form later this week. The disturbance is forecast to move slowly toward the west and then west-northwest at 5 to 10 mph, toward the waters east and northeast of the Leeward Islands. Additional information on this system can be found in high seas forecasts issued by the National Weather Service. * Formation chance through 48 hours...medium...50 percent. * Formation chance through 5 days...high...80 percent. 2. Central Subtropical Atlantic: A small low pressure system located about 600 miles east of Bermuda continues to produce limited shower activity. Strong upper-level winds and dry air are expected to limit significant development of this system while it drifts southward over the central Atlantic during the next day or so, and the low is likely to dissipate by midweek. * Formation chance through 48 hours...low...10 percent. * Formation chance through 5 days...low...10 percent. 3. Eastern Tropical Atlantic: A tropical wave is forecast to move off the west coast of Africa late today or tonight. Some gradual development of the system is possible after that time while it moves generally westward across the far eastern tropical Atlantic. * Formation chance through 48 hours...low...10 percent. * Formation chance through 5 days...low...30 percent. 4. Northwestern Caribbean Sea: A trough of low pressure could develop over the northwestern Caribbean Sea during the middle part of this week. Environmental conditions could support some slow development of the system thereafter while it moves generally west-northwestward over the northwestern Caribbean Sea and toward the Yucatan Peninsula of Mexico. * Formation chance through 48 hours...low...near 0 percent. * Formation chance through 5 days...low...20 percent.