...HIGH SURF ADVISORY FOR NORTH AND WEST FACING SHORES OF NIIHAU KAUAI OAHU MOLOKAI AND NORTH FACING SHORES OF MAUI... .Advisory level surf will decline tonight as a large northwest swell slowly declines. Surf is expected to fall below advisory levels by early Friday. * WHAT...For north-facing shores, surf of 12 to 16 feet. For west- facing shores, surf of 9 to 12 feet. * WHERE...North and west facing shores of Niihau, Kauai, Oahu, Molokai and north facing shores of Maui. * WHEN...Until 6 AM HST Friday. * IMPACTS...Moderate. Strong breaking waves and strong currents will make swimming dangerous.