Guillermo intensified rapidly during the past 24 hours and it is now a hurricane.  At 5:00 p.m. EDT on Friday the center of Hurricane Guillermo was located at latitude 12.7°N and longitude 134.8°W which put it about 1430 miles (2300 km) east of Hilo, Hawaii.  Guillermo was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 970 mb.

Guillermo moved through a very favorable environment of warm Sea Surface Temperatures and little vertical wind shear which allowed it to intensify rapidly from a tropical storm into a hurricane.  An eye was visible earlier today on satellite images, but it is either obscured or has filled with clouds on the most recent images.  The hurricane is moving over water where the Sea Surface Temperature (SST) is near 29°C.  The upper level winds are light, but the rapid movement toward the west-northwest may be generating some vertical wind shear.  If Guillermo moves more slowly, it has about another 24 hours before it starts to move over cooler SSTs.  Once Guillermo gets west of longitude 140°W, it will gradually move over cooler SSTs.  As it moves farther north, it will also get closer to stronger upper level winds blowing from the west.  The combination of cooler SSTs and more vertical wind shear are likely to weaken Guillermo as it approaches Hawaii.

A subtropical ridge north of Guillermo is steering the hurricane toward the west-northwest and that steering is likely to continue for several more days,  In a few days a trough approaching from the west will turn Guillermo toward the northwest.  On its anticipated track Guillermo could approach Hawaii in about five days.  The higher probability is that a weaker Guillermo will move north of Hawaii, but the guidance from numerical models has been changing today.