For the North Atlantic...Caribbean Sea and the Gulf of Mexico: 1. Eastern Tropical Atlantic: A tropical wave located just off the west coast of Africa is producing disorganized showers and thunderstorms over the far eastern tropical Atlantic. Environmental conditions appear generally conducive for gradual development of this system while it moves westward to west-northwestward at 15 to 20 mph across the eastern and central tropical Atlantic, and a tropical depression could form around the middle part of this week. * Formation chance through 48 hours...low...near 0 percent. * Formation chance through 5 days...medium...40 percent.