483 FXHW60 PHFO 121330 AFDHFO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 400 AM HST TUE MAR 12 2013 .SYNOPSIS... LINGERING MOISTURE...TOGETHER WITH A COLD LOW IN THE MIDDLE ATMOSPHERE...WILL PRODUCE SHOWERS OVER MOST OF THE STATE TODAY...AND POSSIBLY THUNDERSTORMS OVER HIGHER SLOPES OF MAUI AND THE BIG ISLAND. SLACK TRADE WINDS AND DRIER CONDITIONS WILL PREVAIL AROUND THE MIDDLE OF THE WEEK...BUT ANOTHER FRONT WILL SPREAD RAIN ACROSS THE STATE OVER THE WEEKEND. && .DISCUSSION... A BROAD AND DEEPLY STACKED TROUGH PERSISTED TO THE NORTH OF THE MAIN HAWAIIAN ISLANDS. THE AIR MASS MOISTENED AT LOWER LEVELS AROUND THE BIG ISLAND OVERNIGHT...WHILE LARGE SWATHS OF CIRRUS OBSCURED MOST OF THE STATE. THE HIGHER CLOUDS ALSO MAY HAVE BEEN SEEDING THE PROLIFERATING SHOWERS OFFSHORE. THUS...THE MORNING LIKELY WILL BECOME WETTER WITH TIME OVER MOST AREAS...THOUGH HEAVY RAIN SHOULD REMAIN RESTRICTED TO A FEW CONVECTIVE SHOWERS. BY THE AFTERNOON... THE AIR MASS MAY BE UNSTABLE ENOUGH TO PRODUCE A FEW THUNDERSTORMS OVER THE SLOPES OF HALEAKALA AND THE BIG ISLAND MOUNTAINS...THOUGH PERSISTENT CIRRUS COVER WILL REDUCE THE LIKELIHOOD OF THIS OUTCOME. WINTER WEATHER HAD NOT MATERIALIZED OVER THE BIG ISLAND SUMMITS OVERNIGHT...AND OBSERVATIONS FROM THERE REPORTED INCREASINGLY DRY CONDITIONS. SOME WINTRY PRECIPITATION MAY BE POSSIBLE TODAY... ESPECIALLY IF THUNDERSTORMS DO DEVELOP ALONG LOWER SLOPES...BUT ACCUMULATION SHOULD BE LIMITED. ON THE OTHER HAND...WINDS OVER THE SUMMITS REMAINED A CONCERN. GUIDANCE AGREED WELL IN PREDICTING THAT THE GRADIENT AT THE ALTITUDE OF THE SUMMITS WILL KEEP WIND SPEEDS HIGH THROUGH MOST OF THE WEEK. A SLIGHT LULL MAY OCCUR ON WEDNESDAY...BUT EVEN STRONGER WINDS ARE EXPECTED TO RESUME ON THURSDAY. INDEED...A HIGH WIND WARNING MAY BE WARRANTED BY LATE IN THE WEEK...AND THIS ISSUE WILL REQUIRE CONTINUED ATTENTION. ELSEWHERE...WIND SPEEDS WILL REMAIN LOW. PREVAILING WIND DIRECTION WILL TURN AROUND TO A MORE TYPICAL TRADE-WIND ORIENTATION TODAY... BUT LOCAL SEA AND LAND BREEZES WILL PERSIST...AT LEAST WHERE CIRRUS COVER PERMITS THE LAND TO HEAT OR COOL SUBSTANTIALLY. FROM THURSDAY INTO THE WEEKEND...LOW-LEVEL WINDS WILL START TO TURN SOUTHEASTERLY AND THEN SOUTHERLY AGAIN AHEAD OF THE NEXT INCOMING FRONT. GUIDANCE PREDICTS THIS FEATURE TO HAVE GOOD SUPPORT FROM ALOFT IN THE FORM OF A RAPIDLY DIGGING LOW WITHIN THE LARGER TROUGH...AND RECENT SOLUTIONS HAVE BEEN EXPECTING IT TO DROP GREATER AND MORE WIDESPREAD PRECIPITATION. SOME DIFFERENCES REMAINED AMONG MODELS...MAINLY ON THE QUESTION WHETHER THE GREATEST PRECIPITATION WILL FALL FROM THE FRONTAL BAND ITSELF...OR FROM PRE-FRONTAL SHOWERS FIRING IN THE MOISTURE FROM THE PREVIOUS FRONT THAT FINALLY REACHES THE ISLANDS. BOTH MAY BE SIGNIFICANT...WITH MAUI COUNTY AND THE BIG ISLAND LIKELY TO RECEIVE MORE PRE-FRONTAL RAIN...BUT KAUAI COUNTY AND OAHU RECEIVING MORE FROM THE FRONT. && .MARINE... A SERIES OF NORTH AND NORTHWEST SWELLS WILL AFFECT THE ISLANDS THROUGH THE WEEK...THOUGH SURF HEIGHTS SHOULD REMAIN BELOW THE HIGH SURF ADVISORY CRITERIA. WIND SPEEDS ALSO SHOULD STAY BELOW SMALL CRAFT ADVISORY CRITERIA...WITH THE MAIN POSSIBLE EXCEPTION OCCURRING AFTER THE FRONTAL PASSAGE AROUND SATURDAY NIGHT. && .HFO WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 6 AM HST WEDNESDAY FOR BIG ISLAND SUMMITS. && $$ RYSHKO