HONOLULU (HawaiiNewsNow) - Hurricane Guillermo is maintaining strength but is still expected to begin weakening as it approaches the main Hawaiian islands.The Central Pacific Hurricane Center (CPHC) said at 5 a.m. Sunday, Guillermo was located about 840 miles east-southeast of Hilo. It was moving toward the west-northwest at 13 miles per hour.Forecasters said Guillermo's maximum sustained winds are still near 105 miles per hour with higher gusts, keeping it as a Category 2 hurricane. It is expected to remain a hurricane through Monday. It is still forecast to weaken into a tropical storm as it moves close to the islands beginning as soon as late Tuesday.Currently, hurricane force winds extend outward up to 30 miles from the center and tropical storm force winds extend outward up to 115 miles. The latest forecast track from the CPHC continues to bring Guillermo very close to the main Hawaiian islands from Wednesday through Thursday night. However, it is far too soon to tell exactly what Guillermo will do, although there is currently a high probability that it will bring possible flooding rain to the islands.Guillermo is expected to begin weakening tonight, as forecasters believe Guillermo's intensity has peaked and that the hurricane will be entering into an environment that isn't favorable for strengthening. Computer forecast models call for strong upper-level winds to strengthen near the Hawaiian islands, which would shear the top of the storm.The forecast discussion from the Central Pacific Hurricane Center said, \It is important not to focus too closely on the exact forecast track of the center of any tropical cyclone