Tropical Storm Sonia formed over the Eastern North Pacific Ocean southwest of Baja California early on Saturday.  At 5:00 a.m. EDT on Saturday the center of Tropical Storm Sonia was located at latitude 13.3°N and longitude 117.6°W which put the center about 835 miles (1340 km) southwest of the southern tip of Baja California.  Sonia was moving toward the west at 9 m.p.h. (15 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 1006 mb.

A low pressure system over the Eastern North Pacific Ocean southwest of Baja California strengthened early on Saturday and the U.S. National Hurricane Center designated the system as Tropical Storm Sonia.

More thunderstorms developed near the center of Tropical Storm Sonia early on Saturday.  Thunderstorms also were forming in bands revolving around the center of Sonia’s circulation.  Storms near the center of Sonia started to generate upper level divergence that pumped mass away from the tropical storm.

The circulation around Tropical Storm Sonia was small.  Winds to tropical storm force extended out 60 miles (95 km) in the northern half of Sonia’s circulation.  Winds to tropical storm force extended out 25 miles (40 km) in the southern side of Tropical Storm Sonia.

Tropical Cyclone Sonia will move through an environment that is favorable for intensification during the next 24 hours.  Sonia will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the eastern side of an upper level trough that is over the Eastern North Pacific Ocean.  The upper level trough will produce southwesterly winds that will blow toward the top of Sonia’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Tropical Storm Sonia will intensify during the next 24 hours.

Tropical Storm Sonia will move around the southern side of a high pressure system over the Eastern North Pacific Ocean.  The high pressure system will steer Sonia toward the west during the next 24 hours.  On its anticipated track, Tropical Storm Sonia will move farther away from Baja California.