WWJP71 RJTD 180000 IMPORTANT WARNING FOR NAHA NAVTEX AREA 180000UTC ISSUED AT 180300UTC PRESSURE GRADIENT IS STEEP WARNING(NEAR GALE) SEA SOUTH OF OKINAWA WARNING(DENSE FOG) SOUTHERN PART OF EAST CHINA SEA POOR VIS 0.3 MILES OR LESS IN PLACES NXT WARNING WILL BE ISSUED BEFORE 180900UTC =