207 FXHW60 PHFO 050626 AFDHFO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HONOLULU HI 830 PM HST THU DEC 4 2008 .SYNOPSIS... A WEAK SURFACE RIDGE LOCATED JUST NORTH OF THE HAWAIIAN ISLANDS IS MAINTAINING LIGHT TO MODERATE TRADE WINDS ACROSS THE ALOHA STATE. CONDITIONS REMAIN MOSTLY DRY...EXCEPT FOR A FEW TRADE WIND SHOWERS AFFECTING MAINLY WINDWARD SLOPES AND MAUKA AREAS DURING THE NEXT FEW DAYS. OUR WINDS WILL SHIFT TO A SOUTHEASTERLY DIRECTION WHEN THE SURFACE RIDGE IS DISPLACED SOUTHWARD OVER THE ISLANDS FROM LATE SATURDAY THROUGH MONDAY AS A NEW FRONT APPROACHES KAUAI. THIS FRONT IS EXPECTED TO REACH KAUAI AND STALL ON TUESDAY. && .DISCUSSION... THE WESTERN END OF A WEAK SURFACE RIDGE IS LOCATED ABOUT 220 MILES NORTH OF HONOLULU THIS EVENING...WHILE A NEARLY STATIONARY FRONT IS LOCATED ABOUT 210 MILES NORTHWEST OF KAUAI. THIS FRONT IS FORECAST TO WEAKEN LATER TONIGHT AND FRIDAY...AS THE RIDGE BUILD NORTH OF THE ISLANDS. THE INCREASING PRESSURE GRADIENT SOUTH OF THE RIDGE WILL ALLOW THE TRADE WINDS TO GRADUALLY INCREASE TO LIGHT TO MODERATE SPEEDS ACROSS MOST OF THE STATE LATER TONIGHT AND FRIDAY. RIDGING ALOFT WILL CONTINUE TO MAINTAIN STABLE CONDITIONS WITH A RATHER DRY WEATHER PATTERN. THERE ARE SOME WINDWARD SHOWERS THAT ARE MAINLY AFFECTING EASTERN MAUI AND THE WINDWARD COAST OF THE BIG ISLAND THIS EVENING. HIGH CLOUDS...MOSTLY THIN CIRRUS...WILL CONTINUE MOVING DOWN FROM THE NORTHWEST ACROSS THE AREA THROUGH FRIDAY. TYPICAL LIGHT TRADE WIND SHOWERS CAN EXPECTED FRIDAY AND SATURDAY. A WIND ADVISORY WAS ISSUED FOR BIG ISLAND SUMMITS SINCE WINDS ARE EXPECTED TO BE NEAR OR ABOVE THE ADVISORY CRITERIA OF 30 MPH LATER TONIGHT OVER THE HIGHER SUMMITS AS NORTHEAST FLOW AROUND AN UPPER TROUGH TO THE EAST OF THE STATE INCREASES. WINDS HAVE BEEN INCREASING DURING THE PAST COUPLE OF HOURS AT A NUMBER OF REPORTING STATIONS ON THE SUMMITS. THE SURFACE RIDGE WILL WEAKEN AND BEGIN TO SHIFT SOUTHWARD AGAIN BY SATURDAY AFTERNOON. THIS WILL ALLOW OUR WINDS TO DIMINISH AND SHIFT TO A MORE SOUTHEASTERLY FROM SATURDAY NIGHT THROUGH MONDAY. THIS WILL ALLOW A WEAK DIURNAL DAYTIME SEABREEZE AND NIGHTTIME LANDBREEZE PATTERN TO DEVELOP FROM SUNDAY INTO TUESDAY. A FRONT IS EXPECTED TO APPROACH KAUAI FROM THE NORTHWEST LATE MONDAY AND BE NEAR THAT ISLAND BY TUESDAY. THERE IS THE POSSIBILITY OF SOME HEAVY SHOWERS TUESDAY AS ATMOSPHERIC INSTABILITY INCREASES NEAR KAUAI AND OAHU WITH A WEST SOUTHWESTERLY FLOW ALOFT AND POSSIBLE MOISTURE ASSOCIATED WITH THE FRONT. GLOBAL MODEL RUNS CONTINUE TO SHOW SOME DISAGREEMENT FOR THE MIDDLE AND END OF NEXT WEEK. ONE...OR MAYBE TWO...SURFACE LOWS THEN DEVELOP BETWEEN KAUAI AND THE DATELINE WHICH IMPLIES A STRONGER SOUTHERLY FLOW. THIS COULD MEAN A WETTER WEATHER FOR THE WESTERN END OF THE MAIN HAWAIIAN ISLAND CHAIN FOR THE SECOND HALF OF NEXT WEEK. && .MARINE... THE REINFORCED WEST NORTHWEST SWELL CONTINUES TO BUILD ACROSS THE HAWAIIAN COASTAL WATERS EARLY THIS EVENING. READINGS FROM BUOY 51001 NORTHWEST OF KAUAI INDICATE THE SWELL HEIGHT IS ABOUT 13 FEET WITH A PERIOD 16 SECONDS FROM 310 DEGREES...WHILE THE WAIMEA BAY BUOY JUST NORTH OF OAHU HAS A SIGNIFICANT WAVE HEIGHT OF AROUND 9 FEET WITH A PERIOD OF 14 SECONDS FROM 310 DEGREES. BOTH BUOYS CONTINUE TO SHOW STRONG ENERGY AT THE LONGER PERIODS...MAINLY BETWEEN 14 AND 18 SECONDS. HOWEVER...THEY ARE ALSO SHOWING SOME ENERGY IN EXCESS OF 20 SECONDS. THIS SWELL IS EXPECTED TO PEAK ALONG THE SMALLER ISLANDS EARLY FRIDAY. THE PEAK SHOULD BE LATER DURING THE DAY ON FRIDAY ALONG THE LEEWARD BIG ISLAND. THE HIGH SURF WARNING IS CURRENTLY IN EFFECT FOR NORTH AND WEST SHORES OF NIIHAU...KAUAI... OAHU AND MOLOKAI...FOR NORTH FACING SHORES OF MAUI...AND FOR WEST FACING SHORES OF THE BIG ISLAND. THE WARNING IS IN EFFECT THROUGH FRIDAY NIGHT. SURF PRODUCED BY THIS SWELL MAY DROP BELOW THE HIGH SURF ADVISORY THRESHOLD BY LATE SATURDAY NIGHT. THERE MAY BE PROBLEMS FROM WAVE RUNUP ALONG SOME LOCATIONS ALONG THE LEEWARD BIG ISLAND...ESPECIALLY AT THE THE TIMES OF HIGH TIDE ON FRIDAY. ALTHOUGH THERE MAY BE SOME SIGNIFICANT WAVE RUNUP ALONG NORTH AND WEST FACING SHORES OF THE SMALLER ISLANDS THAT ARE TYPICALLY SUSCEPTIBLE TO BREAKING SURF...THE HIGH TIDES ARE NOT AT THEIR MAXIMUM. SO DESPITE THE CAUTION THAT SHOULD ALWAYS BE EXERCISED AROUND COASTS AFFECTED BY HIGH SURF...THE SHORELINE SURF EFFECTS WILL PROBABLY BE NO MORE THAN NORMALLY EXPERIENCED WITH A LARGE SWELL. SMALL CRAFT ADVISORIES REMAIN IN EFFECT FOR ALL HAWAIIAN WATERS... EXCEPT MAALAEA BAY DUE TO THE LARGE WEST NORTHWEST SWELL. THE SMALL CRAFT ADVISORY IS CURRENTLY IN EFFECT THROUGH FRIDAY NIGHT. && .HFO WATCHES/WARNINGS/ADVISORIES... HIGH SURF WARNING UNTIL 600 AM HST SATURDAY FOR NORTH AND WEST SHORES OF NIIHAU...KAUAI...OAHU AND MOLOKAI...FOR NORTH FACING SHORES OF MAUI...AND FOR WEST FACING SHORES OF THE BIG ISLAND. SMALL CRAFT ADVISORY UNTIL 6 AM HST SATURDAY FOR ALL HAWAIIAN WATERS...EXCEPT MAALAEA BAY. && $$ HOUSTON