Hurricane Sandra moved around the western end of a subtropical ridge and turned toward Mexico on Thursday.  At 10:00 p.m. EST on Thursday the center of Hurricane Sandra was located at latitude 18.0°N and longitude 109.7°W which put it about 340 miles (545 km) south of the southern tip of Baja California and about 490 miles (790 km) south-southwest of Culiacan, Mexico.  Sandra was moving toward the north at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 956 mb.  The government of Mexico issued a Tropical Storm Watch for the coast of Baja California from Todos Santos to Los Barriles.

Hurricane Sandra appeared to develop concentric eyewalls on Thursday.  A primary rainband wrapped around the tiny pinhole eye at the center of the hurricane.  Satellite imagery suggests that the tiny inner eye still exists inside the larger outer eye.  Sandra reached Category 4 on the Saffir-Simpson Scale on Thursday morning, but the formation of concentric eyewalls weakened the hurricane back to Category 3 later in the day.  Sandra remains a well organized hurricane.  It has a well defined core surrounded by a ring of strong thunderstorms.  Spiral bands of storms are in the northeastern quadrant of the circulation.

Hurricane Sandra will move into a less favorable environment on Friday.  It will be over water where the Sea Surface Temperature is near 29°C.  However, a large upper level trough along the west coast of North America will generate strong southwesterly winds.  Those winds will cause strong vertical wind shear, which will tilt the circulation toward the northeast.  The upper level winds will also inhibit upper level divergence from the western part of Sandra.  The strong wind shear will weaken Hurricane Sandra on Friday.  Some models are predicting that the shear could be strong enough to blow the middle and upper parts of the circulation northeast of the low level circulation.  If that happens, then Hurricane Sandy could weaken very quickly,

The upper level trough will steer Hurricane Sandra toward the northeast on Friday.  Sandra will likely move faster toward the northeast by Friday night.  On its anticipated track Sandra could be near the southern tip of Baja California by Friday night and it could approach the west coast of Mexico on Saturday.  Sandra could still be a hurricane when it nears Baja California, but it is more likely to be a tropical storm.  It could be a tropical storm or depression by the time it reaches the west coast of Mexico.