Tropical Storm Julio developed south of Mexico on Saturday afternoon. At 5:00 p.m. EDT on Saturday the center of Tropical Storm Julio was located at latitude 16.1°N and longitude 102.7°W which put it about 180 miles (290 km) south-southwest of Zihuatanejo, Mexico. Julio was moving toward the west-northwest at 20 m.p.h. (32 km/h). The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h). The minimum surface pressure was 1005 mb.
The middle and upper portion of the circulation around former Hurricane Nana moved westward from Guatemala over the Gulf of Tehuantepec south of Mexico. A surface circulation redeveloped over the Eastern North Pacific Ocean. More thunderstorms formed near the center of the surface circulation and the National Hurricane Center designated the system as Tropical Storm Julio on Saturday afternoon.
The circulation around Tropical Storm Julio was small. Winds to tropical storm force only extended out 35 miles from the center of Julio. The stronger winds were occurring north of the center of circulation. Thunderstorms continued to form near the center. Short, narrow bands of showers and thunderstorms were revolving around the center of circulation.
Tropical Storm Julio will move through an environment only marginally favorable for intensification. Julio will move over water where the Sea Surface Temperature is near 30°C. So, there is sufficient energy in the upper ocean to support intensification. However, an upper level ridge over Mexico will produce easterly winds which will blow toward the top of Julio. Those winds will cause moderate vertical wind shear which will inhibit intensification. In addition, visible satellite images suggest that there is another small low pressure system about 250 miles (400 km) west of Tropical Storm Julio. Interaction with the small low pressure system could also disrupt the circulation around Julio.
The ridge over Mexico will steer Tropical Storm Julio toward the west-northwest. However, interaction with the small low pressure system west of Julio could also affect the track. On its anticipated track Tropical Storm Julio will move toward a position south of Baja California on Sunday night.