The government of Mexico issued a Tropical Storm Watch for the southern portion of Baja California.  At 5:00 p.m. EDT on Friday the center of Hurricane Blanca was located at latitude 15.3°N and longitude 107.5°W which put it about 550 miles (880 km) south-southeast of Cabo San Lucas, Mexico and about 330 miles (535 km) southwest of Manzanillo, Mexico.  Blanca was moving toward the northwest at 9 m.p.h. (15 km/h).  The maximum sustained wind speed was 90 m.p.h. (150 km/h) and there were gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 976 mb.  The Hurricane Intensity Index (HII) was 13.9, the Hurricane Size Index (HSI) was 17.7 and the Hurricane Wind Intensity Size Index (HWISI) was 31.6.  A reconnaissance aircraft investigated Blanca on Friday afternoon and so there is high confidence in the data about its strength and position.  The government of Mexico issued a Tropical Storm Watch for the portion of the coast from La Paz to Santa Fe including Cabo San Lucas.

Satellite imagery and data from the reconnaissance plane indicate that the structure of Blanca is more well organized.  A ring of thunderstorms surrounds a circular eye with a diameter of about 60 miles (65 km).  However, the better organization has not produced an increase in the wind speed as yet.  However, the aircraft did find winds to 105 m.p.h. (170 km/h) in the northwestern portion of the eyewall.  If downdrafts in thunderstorms in the eyewall bring those winds to the surface, then there could be some intensification.

Blanca is moving over water where the Sea Surface Temperature (SST) is about 29°C and there is sufficient energy in the upper ocean to support some increase in wind speed.  As the hurricane moves farther north it will move over cooler SSTs and when it gets near latitude 20°N in about 36 hours, it will start to move over much cooler water.  So, there is a potential for some intensification on Saturday, but Blanca will start to weaken as it approaches the southern tip of Baja California on Sunday.

A ridge northeast of Blanca and a trough west of Baja California are combining to steer Blanca toward the northwest.  As it moves farther north, it is likely to turn a little more toward the north.  Blanca is likely to approach the southern tip of Baja California on Sunday which is the reason for the Tropical Storm Watch.