USSR CROP WEATHER SUMMARY -- USDA/NOAA Gradual warming continued in most regions of Western Soviet Union in the week ended April 4, the Joint Agricultural Weather Facility of the U.S Agriculture and Commerce Departments said. In its International Weather and Crop Summary, the agency said most of the region's precipitation fell as rain. The southern snow cover boundary continued to slowly retreat northward and eastward, it said. Moderate to deep snow cover the northern half of the Ukraine, northern North Caucasus, and the lower Volga, about one month later than usual, it said. The agency said average weekly temperatures were below normal in the southeast, near normal in the southwest and northeast, and above normal in the northwest. Winter grains remained dormant over the region, but warm weather promoted greening in crop areas adjacent to the Black Sea coast, it said.