Hurricane Guillermo moved west of longitude 140°W on Saturday, which means it officially crossed into the Central Pacific Ocean.  The responsibility for issuing advisories on Guillermo shifted from the National Hurricane Center in Miami, Florida to the Central Pacific Hurricane Center in Honolulu, Hawaii when Guillermo moved west of 140°W.  At 11:00 p.m. EDT on Saturday the center of Hurricane Guillermo was located at latitude 14.0°N and longitude 141.0°W which put it about 1010 miles (1625 km) east-southeast Hilo, Hawaii.  Guillermo was moving toward the west-northwest at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 970 mb.

The structure of Hurricane Guillermo appeared to become less organized on Saturday.  There are fewer thunderstorms and the spiral bands appear to be weaker.  Guillermo is nearing water where the Sea Surface Temperature is near 27°C, and it will gradually move over even cooler water.  Westerly winds in the upper levels appear to be generating some vertical wind shear over the northern portion of the circulation.  Guillermo is still producing upper level divergence near the center of circulation, but the divergence appears to less over the western half of the hurricane.  The circulation may be pulling some drier more stable air into the western part of the circulation.  Guillermo will be moving into a less favorable environment and weakening is likely.

A subtropical ridge is steering Guillermo toward the west-northwest and that general motion is expected to continue during the next several days.  On its anticipated track Guillermo could approach the Big Island of Hawaii in about four days.  It is likely to be a tropical storm at that time.